Iodine Nutrition and Related Factors of Mothers with Children under 2 Years Old from Three Different Areas in China: A Cross-sectional Survey

Iodine Nutrition and Related Factors of Mothers with Children under 2 Years Old from Three Different Areas in China: A Cross-sectional Survey | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Iodine Nutrition and Related Factors of Mothers with Children under 2 Years Old from Three Different Areas in China: A Cross-sectional Survey Xiaoyun Shan, Yan Zou, Lichun Huang, Shan Jiang, Weiwen Zhou, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1485512/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract To analyze the iodine nutritional status and related factors of mothers with children under 2 years old, we collected data from the 2016–2017 National Nutrition and Health Surveillance of Children and Lactating Women. A total of 1311 mothers from Hebei, Zhejiang, and Guangxi province were included in the study. Urinary iodine concentration (UIC), thyroid-stimulating hormone (TSH), body mass index (BMI), vitamin A (VA), and vitamin D (VD) were measured. The distributions of UIC and TSH were assessed. Relationships between UIC, TSH and the possible factors were analyzed. The median UIC (MUIC) (P 25 -P 75 ) of total mothers and mothers in lactation was 142.00 µg/L (99.10-209.40 µg/L) and 139.95 µg/L (96.22-208.03) µg/L, respectively. No differences in UI were found between breastfeeding mothers and non-breastfeeding mothers. The prevalence of mothers with UICs < 50µg/L was 5.03%, and 91.30% of mothers showed TSH normality. UICs and UIC distributions were significantly different among the three provinces, and between rural and urban areas. Obese mothers tended to have higher MUIC and higher prevalence of excessive TSH. Linear correlations between lnUIC and VA/VD were observed with or without adjusting for confounding factors. Higher TSHs were observed in both VD deficiency and insufficiency groups ( P < 0.01). However, typical U-shaped relationship between TSH and UIC was not observed in this population. In conclusion, Mothers in our study had no iodine deficiency, but numbers of mothers were still having a UIC of 300 µg/L. Region, area type, age, BMI, VA, or VD should be taken into consideration in the future iodine evaluation and surveillance. Median urinary iodine concentration Thyroid-stimulating hormone Vitamin A Vitamin D Mothers with children under 2 years old Figures Figure 1 Introduction Iodine is an essential trace element for the synthesis of thyroid hormones. And iodine status is particularly important for pregnant and lactating women, since iodine deficiency disorders (IDD) affects fetuses in utero and infants through breastfeeding, which may lead to impaired neurological development [ 1 ]. On the other hand, high prevalence of thyroid dysfunction caused by iodine excess, has also become a problem over the past years [ 2 ]. Therefore, adequate iodine nutrition is critical for susceptible populations including pregnant and lactating women as well as infants, who have higher iodine demand. In addition, as mothers with children under 2 years old in China have the dual heavy pressure of breastfeeding and returning to work, it is also very important to ensure appropriate iodine and other nutrients. Iodine is mainly obtained from diet. A systematic review indicated that the doubling of dietary iodine intake could increase urinary iodine concentrations (UICs) in different populations [ 3 ]. A recent survey from 13 provinces and municipalities in China showed that the dietary iodine intake of lactating women was much lower than the recommended levels [ 4 ], but two studies from Guangxi and Henan Province in China demonstrated that the median UICs (MUICs) of lactating women were both at the appropriate levels [ 5 , 6 ]. This phenomenon suggests that the overall iodine nutritional status may not represent the regional situation. Therefore, it is necessary to analyze the iodine nutritional status in areas with different geographical characteristics. According to the 2014 monitoring data of IDD in China, the overall level of urinary iodine in the eastern region was lower than that in the central and western regions [ 7 ]. As Hebei, Zhejiang, Guangxi in eastern China were historically areas with cretinism and low iodized-salt coverage rates [ 8 ], we previously assessed the iodine nutritional status among school-age children in the three representative provinces, which showed that lower MUIC and higher proportion of < 100 µg/L was observed in Hebei and Zhejiang, compared to Guangxi [ 9 ]. So similar study is warranted among mothers with children under 2 years old. Vitamin A (VA) deficiency (VAD), vitamin D (VD) deficiency (VDD) and IDD often coexist in vulnerable groups, such as lactating women. As VAD has multiple effects on the pituitary-thyroid axis, studies indicated that concurrent VA supplementation with iodized salt could improve iodine efficacy in IDD- and VAD-affected children [ 10 ]. VD can also act in the immune system, and its deficiency is associated with Hashimoto’s thyroiditis [ 11 ]. For example, a significant association between VDD and high prevalence of thyroid autoimmunity and dysfunction in participants with excessive iodine intake was found in the Korean population [ 12 ]. And our previous study showed the iodine nutritional status of children and adolescents was related to VA and VD [ 9 ]. It is also necessary to analyze the relationship between iodine nutritional status and VA/VD in mothers with children under 2 years old. At present, few studies about the relationships between iodine nutrition and other factors (including vitamins, region, age and body mass index (BMI)) were carried out on lactating women, especially on mothers with children under 2 years old. Therefore, this study intended to study the iodine status of mothers with children under 2 years old and analyze its related factors, so as to provide reference for iodine nutrition monitoring of mothers and their newborns. Materials And Methods Study Regions and Subjects The data were collected from the 2016–2017 National Nutrition and Health Surveillance of Children and Lactating Women, a large-scale cross-sectional survey. Three provinces in eastern China including Hebei Province in the north, Guangxi Province in the south, and Zhejiang Province in the east coast were selected. Mothers with children under 2 years old were investigated and sampled [ 13 , 14 ]. Inclusion criteria were: i) having been breastfeeding after this delivery; ii) no chronic diseases; iii) no thyroid disease or usage of thyroid drugs. Subjects were selected by using the multi-stage stratified cluster randomization sampling method. The national sample size was calculated according to the anemia rate of lactating mothers in 2013. The formula was as follows: N, number of samples; Deff (design effect) = 2.0; p (anemia rate) = 9.3%; r (relative standard error) = 11%; The confidence level ((bilateral) was 95%, then u = 1.96. There were four types of areas (large cities, small cities, ordinary rural areas and poor rural areas), and the nonresponse rate was 10%. The sample size was about 27500 (covering 275 districts or counties ). Moreover, according to the proportion (32.9%) of UIC < 100 µg/L among lactating women in Guangxi, the calculated sample size was 314 [ 5 ]. Then 100 participants were included in each district or county. Four types of areas were chosed from each district or county. And at least 25 mothers were randomly selected from each type of area. At last, 1500 mothers were included in the three province (containing 5 districts or counties in each province, with non-high water iodine). Participants with missing anthropometric indexes or missing UIC, thyroid-stimulating hormone (TSH), VA and VD measurements, were excluded. Participants with other missing pertinent covariates were also excluded. The data from 1311 participants were ultimately included in the present analysis. Written informed consent was obtained from all individual participants included in the study. This study was approved by the Ethical Review Committee of Center for Disease Control and Prevention (CDC), and all the documentations and procedures complied with the ethical standards of the committee. Anthropometric Measurements and Chemical Analyses Inquiry survey, anthropometric measurement, blood and urine samples collection were intensively performed in the community or village. Height in cm and weight in kg were measured directly by trained interviewers who followed standard protocols similar to the National Health and Nutrition Examination Survey (NHANES) protocol. Height and weight were measured to the nearest 0.1 cm and 0.1 kg respectively without shoes and wearing light clothing only. BMI was calculated in kg divided by height in square meters (kg/m 2 ). . Blood and urine samples were analyzed in laboratories at the provincial level. All laboratories should have passed the examination of the National Reference Laboratory, China CDC. A random spot midstream urine sample was collected in the morning from 08:30 to 12:00 (approximately 8–10 mL) from all participants. After collection, urine samples were stored in polyethylene plastic tubes and sealed tightly to prevent evaporation. Samples should avoid contact with iodized articles during transportation and be stored at − 20 ℃ until analysis. UIC was measured using arsenic and cerium catalysis spectrophotometry after digestion in ammonium sulfate solution (WS/T 107.1–2016). Blood samples (6 mL) were collected from the cubital vein of the mothers and stored in gel vacuum collective tubes. Blood samples were centrifuged at 3000 rpm for 10 minutes at room temperature as soon as possible.The serum was then stored in a frozen plastic tube made of 99.9% biological grade polypropylene. If not tested immediately, the serum samples were subsequently frozen at − 80℃ until analysis. TSH levels were determined using an automated chemiluminescence immunoassay analyzer (Roche, German). High-performance liquid chromatography was used to determine the serum retinol concentration (WS/T 553–2017). The VD (25(OH)D) level was determined using liquid chromatography-mass spectrometry (WS/T 677–2020).. All the reference ranges of the included parameters are shown in Table 1 : Table 1 Reference range of related parameters Parameter Reference range Identification BMI [ 15 , 16 ] < 18.5 kg/m 2 18.5–23.9 kg/m 2 24.0-27.9 kg/m 2 ≥ 28 kg/m 2 Underweight Normal range Overweight Obese MUIC [ 17 , 18 ] 100–299 µg/L and proportion of < 50 µg/L was ≤ 20% Adequate iodine intake TSH (Roche Kit) 0.27–4.20 mIU/L Normal range VA < 0.2 µg/mL 0.2–0.3 µg/mL ≥ 0.3 µg/mL Deficiency Marginal deficiency Sufficiency VD < 30 nmol/L (12ng/mL) 30–50 nmol/L (12–20 ng/mL) ≥ 50 nmol/L (20 ng/mL) Deficiency Insufficiency Sufficiency MUIC: median urinary iodine concentration, TSH: thyroid-stimulating hormone, BMI: body mass index, VA: vitamin A, VD: vitamin D Statistical Analysis Data processing and statistical analyses were carried out using IBM SPSS Statistics 23. Kolmogorov–Smirnov (KS) test was used for normality test. If the indicator was not normally distributed, it was expressed as median and P 25 -P 75 . 95% confidence interval (CI) of UIC was also used to test whether statistical difference existed between relevant cut-off point (100 µg/L) and the MUIC, just as the 2018 Guidance on the Monitoring of Salt Iodization Programmes and Determination of Population Iodine Status recommended [ 17 ]. Nonparametric statistical test was used to compare age, BMI, UIC, TSH, VA or VD differences among the groups (region, area type, lactation, age, BMI, VA or VD groups ). A two-way ANOVA model was performed to analyze the interaction effect. The chi-square test was used to compare the difference of categorical variables. As UIC and TSH showed skewed distribution, they were ransitioned with ln. Then simple linear regression and multiple linear regression were used to analyze the linear relationship between VA, VD and lnUIC as well as lnTSH. The generalized linear model of the relationship between UIC, TSH and possible factors (VA and VD) was established. Potential confounders, including area type, age (continuous), and BMI (continuous) were introduced as covariates in the adjusted models. Data were considered statistically significant at P < 0.05. Results Description of the Population Characteristics of the participants are presented in Table 2 . The median age and BMI of the participants were 30.04(P 25 -P 75 : 27.15–34.23)years and 22.78 (P 25 -P 75 : 20.65–25.41) kg/m 2 , respectively. BMI in Hebei was higher than that of the other two provinces ( P < 0.05). More than half of the mothers had the second child, and 68.34% of mothers were still breastfeeding at that moment. Table 2 Characteristics of Chinese mothers from three different regions (median, P 25 –P 75 ) Characteristics Hebei (n = 493) Zhejiang (n = 429) Guangxi (n = 389) Total (n = 1311) Rural (%) 289(60.45) 244(56.88) 172(44.22) * 714(54.46) Number of children (%) 1 185(37.53) 170(39.63) 119(30.59) 474(36.16) 2 293(59.43) 247(57.58) 239(61.44) 779(59.42) ≥ 3 15(3.04) 12(2.79) 31(7.97) 58(4.42) In lactation (%) Yes 382(77.48) 262(61.07) 252(64.78) 896(68.34) No 111(22.52) 167(38.93) 137(35.22) 415(31.66) Age (years) 30.00 (27.00–33.00) 31.07 (28.19–35.94) * 30.25 (26.99–33.84) 30.04 (27.15–34.23) BMI(kg/m 2 ) 23.82 (21.61–26.31) * 22.29 (20.44–24.92) 22.03 (20.17–24.51) 22.78 (20.65–25.41) BMI: body mass index, *: Compared with the other two provinces, P < 0.05 Urinary Iodine, Thyroid-stimulating Hormone, Vitamin A and Vitamin D Levels in the Three Provinces Table 3 showed the levels and differences of parameters among the three provinces. Median serum UIC, TSH, retinol and 25(OH)D levels of the total population were all in the normal ranges. UIC (Median: 166.10, P 25 -P 75 : 116.25-228.95, µg/L) and TSH (Median: 2.11, P 25 -P 75 : 1.48–2.87, mIU/L) in Hebei were the highest ( P < 0.05), while 25(OH)D (Median: 17.20, P 25 -P 75 : 13.70-21.82, ng/mL) levels was the lowest ( P < 0.05), with an average level less than 20 ng/mL. Moreover, UIC and retinol were different from each other province ( P < 0.05). Table 3 Parameters of Chinese mothers from three different regions (Median, P 25 -P 75 ) Parameters Hebei (n = 493) Zhejiang (n = 429) Guangxi (n = 389) Total (n = 1311) UIC(µg/L) 166.10 (116.25-228.95) * 123.58 (86.42-185.04) * 139.40 (90.80-206.15) * 142.00 (99.10-209.40) TSH (mIU/L) 2.11 (1.48–2.87) * 1.72 (1.21–2.34) 1.86 (1.24–2.50) 1.89 (1.32–2.59) Retinol (µg/mL) 0.43 (0.37–0.54) * 0.36 (0.30–0.45) * 0.51 (0.44–0.59) * 0.44 (0.36–0.53) 25 (OH) D (ng/mL) 17.20 (13.70-21.82) * 28.26 (23.39–34.14) 26.40 (23.40–30.20) 24.04 (18.20–29.00) UIC: urinary iodine concentration, TSH: thyroid-stimulating hormone. *: Compared with the other two provinces, P < 0.05 Urinary Iodine Concentrations and Distributions As shown in Table 4 , the MUIC of total mothers and mothers in lactation was 142.00 (95% CI: 40.74-358.97) µg/L and 139.95 (96.22-208.03) µg/L, respectively. No significant differences in UI were found between breastfeeding mothers and non-breastfeeding mothers. And only 5.42% of mothers showed UIC ≥ 300 µg/L. The proportion of UIC values < 100 µg/L was 25.32%, while only 5.03% of mothers had UIC < 50 µg/L. The mothers in the three provinces all had no iodine deficiency. Zhejiang had the lowest UIC and highest rate of < 50 µg/L (123.58 µg/L and 6.99% respectively, P < 0.01), while Hebei was in the opposite. And the MUIC in the rural was higher than that in the urban ( P < 0.05). As differences in the proportion of urban and rural population existed among the three provinces, we further analyzed whether the relationship between region and UIC was affected by area type by a two-way ANOVA model. Results showed that there was interaction effect between region and area type (data not shown). Although more mothers in 18 ~ years group were showing UIC < 50 µg/L ( P 0.05). The MUIC was the highest among the obese mothers ( P 0.05), but the UIC seemed to be lower in VA deficiency group. On the contrary, the MUIC in VD deficiency group was the highest, and more mothers in the VD deficiency group showed UIC between 100–299 µg/L ( P < 0.05). Table 4 Median and frequency distributions of UIC among Chinese mothers Factors N MUIC, 95%CI (µg/L) Frequency Distribution (%) Per UIC Range, µg/L < 50 50~ 100~ ≥ 300 P Region 0.000 Hebei 493 (37.61) 166.10 (48.88-336.18) a, b 13(2.64) 64(12.98) 385(78.09) # 31(6.29) Zhejiang 429 (32.72) 123.58 (32.41-399.95) c 30(6.99) # 115(26.81) # 270(62.94) 14(3.26) # Guangxi 389 (29.67) 139.40 (39.48-419.55) 23(5.91) 87(22.37) 253(65.04) 26(6.68) Area type 0.001 Rural 714 (54.46) 159.80 (46.54-377.42) d 23(3.22) 130(18.21) 517(72.41) 44(6.16) Urban 597 (45.54) 125.30 (34.03-342.88) 43(7.20) # 136(22.78) 391(65.49) 27(4.52) In lactation 0.309 Yes 896 (68.34) 139.95 (96.22-208.03) 46(5.13) 194 (21.65) 607 (67.75) 49 (5.47) No 415 (31.66) 148.69(104.40-211.80) 20(4.82) 72 (17.35) 301 (72.53) 22 (5.3) Age (years) 0.012 18~ 129 (9.84) 142.00 (33.28-411.05) 14(10.85) # 28(21.71) 78(60.47) 9(6.98) 25~ 883 (67.35) 146.00 (38.32-355.14) 45(5.10) 175(19.82) 620(70.22) 43(4.87) 35~ 299 (22.81) 136.13 (49.69-368.02) 7(2.3.4) 63(21.07) 210(70.23) 19(6.35) BMI 0.387 Underweight 89 (6.79) 152.14 (34.78-478.78) 6(6.74) # 20(18.06) 56(62.92) 7(7.87) Normal weight 725 (55.30) 140.90 (37.56-405.25) 39(5.38) 144(19.86) 501(69.10) 41(5.66) Overweight 335 (25.55) 131.30 (44.37-355.34) 14(4.18) 77(22.99) 232(69.25) 12(7.46) Obesity 162 (12.36) 169.55 (43.22-335.92) e 7(4.32) 25(15.43) 119(73.46) 11(6.79) VA 0.567 Deficiency 17 (1.30) 119.34 (66.98-249.44) 0(0.00) 5(31.25) 11(68.75) 0(0.00) Marginal deficiency 129 (9.84) 140.02 (30.60-497.44) 8(6.20) 27(20.93) 86(66.67) 8(6.20) Sufficiency 1165 (88.86) 142.40 (40.88-355.12) 58(4.98) 234(20.09) 810(69.52) 63(5.41) VD 0.036 Deficiency 78 (5.95) 175.10 (41.48–341.40) f 2(2.56) 8(10.26) # 63(80.77) # 5(6.41) Insufficiency 340 (25.93) 159.30 (42.22-329.64) g 16(4.71) 57(16.76) 247(72.65) 20(5.88) Sufficiency 893 (68.12) 133.86 (37.49-389.36) 48(5.37) 201(22.51) # 598(66.97) 46(5.15) Total 1311 (100) 142.00(40.74-358.97) 66(5.03) 266(20.29) 908(69.26) 71(5.42) MUIC: median urinary iodine concentration, TSH: thyroid-stimulating hormone, BMI: body mass index, VA: vitamin A, VD: vitamin D. a: Hebei vs. Zhejiang; b: Hebei vs. Guangxi; c,: Zhejiang vs Guangxi;d: Rural vs. Urban; e: Overweight vs. Obesity; f: deficiency vs. sufficiency༛g: insufficiency vs sufficiency; # : group differences. Statistical significance was considered when P < 0.05. Relationship between Urinary Iodine Concentration and Vitamin A/Vitamin D Nutritional Status Considering that whether mothers were in lactation had no influence on UIC and UIC distribution, we took all mothers as a whole for the following analysis. Simple linear regression analysis showed that lnUIC was positively correlated with total VA (β = 0.095, P = 0. 014), but negatively correlated with total VD (β=- 0.007, P = 0.000). After adjusting for variables including area type, age and BMI, lnUIC was still positively correlated with total VA (β = 0.127, P = 0. 001) and total VD (β=- 0.007, P = 0. 000). However, generalized linear model analysis indicated that UIC were not correlated with the nutritional status of VA after stratification, with or without adjusting for the covariates ( P > 0.05). UICs in VD insufficient group and deficient group were higher than that in sufficient group (β insufficiency = 15.503, P = 0. 005; β deficiency = 26.999, P = 0. 008) when the covariates were not adjusted. After adjusting for the variables of area type, age and BMI, UIC was no longer related to VD nutritional status ( P > 0.05) (Table 5 ). Table 5 Association between lnUIC or UIC and VA/VD nutritional status Factors lnUIC or UIC β (95% CI) SE P VA-Model 1 Total* 0.095 (0.019 ~ 0.170) 0.038 0.014 Deficiency -21.243 (-62.504 ~ 20.018) 21.052 0.313 Marginal deficiency 1.949 (-13.723 ~ 17.621) 7.996 0.807 Sufficiency 0 VA-Model 2 Total* 0.127 (0.052 ~ 0.203) 0.039 0.001 Deficiency -10.306 (-51.434 ~ 30.822) 20.984 0.623 Marginal deficiency 5.770 (-10.346 ~ 21.885) 8.222 0.483 Sufficiency 0 VD-Model 1 Total* -0.007(-0.011~-0.003) 0.002 0.000 Deficiency 26.999 (7.149 ~ 46.849) 10.128 0.008 Insufficiency 15.503 (4.789 ~ 26.216) 5.466 0.005 Sufficiency 0 VD-Model 2 Total* -0.007 (-0.010~-0.003) 0.002 0.000 Deficiency 7.901 (-13.600 ~ 29.403) 10.970 0.471 Insufficiency 1.981 (-10.533 ~ 14.496) 6.385 0.756 Sufficiency 0 UIC: urinary iodine concentration, VA: vitamin A, VD: vitamin D. Model 1: unadjusted;Model 2༚adjusted for area type, age and BMI. *: Regression analysis between total VA or VD and lnUIC. Statistical significance was considered when P < 0.05. Thyroid-stimulating Hormone Concentrations and Distributions Table 6 showed that the median TSH of the mothers was within the reference range, and the overall TSH exceeding rate was only 6.41%. There were no significant differences in TSH among different area type, age, VA and UIC groups ( P > 0.05). TSH level in Hebei (Median: 2.11 mIU/L) was the highest. In addition, we found that BMI was associated with the distribution of TSH, and overweight and obese mothers had the highest excessive rate of TSH ( P < 0.05). Moreover, TSHs in VD deficiency group and insufficiency group were higher than that in sufficiency group ( P < 0.05). But no typical U-shaped relationship between TSH and UIC was observed. Table 6 TSH concentrations and distributions among mothers in the three provinces Factors N Median (P 25 –P 75 ), mIU/L Frequency Distribution (%) Per TSH Range, mIU/L < 0.27 0.27–4.20 ≥ 4.20 P Region 0.072 Hebei 493 (37.61) 2.11(148 − 2.87) a, b 13(2.64) 437(88.64) 43(8.72) Zhejiang 429 (32.72) 1.72 (1.21–2.34) 11(2.56) 397(92.54) 21(4.90) Guangxi 389 (29.67) 1.86 (1.24–2.50) 6(1.54) 363(93.32) 20(5.14) Area type 0.053 Rural 714 (54.46) 1.89 (1.32–2.66) 18(2.52) 640(89.64) 56(7.84) Urban 597(45.54) 1.89( 1.32–2.58) 12(2.01) 557(93.30) 28(4.69) Age (years) 0.910 18~ 129 (9.84) 1.88 (1.30–2.66) 3(2.33) 117(90.70) 9(6.98) 25~ 883 (67.35) 1.86 (1.31–2.59) 19(2.15) 805(91.17) 59(6.68) 35~ 299 (22.81) 1.96 (1.41–2.59) 8(2.68) 275(91.97) 16(5.35) BMI 0.001 Underweight 89 (6.79) 2.07 (1.31–2.72) 0(0.00) 88(98.88) # 1(1.12) Normal weight 725 (55.30) 1.86 (1.32–2.53) 16(2.21) 672(92.69) 37(5.10) Overweight 335 (25.55) 1.92 (1.31–2.77) 12(3.58) 292(87.16) 31(9.25) # obesity 162 (12.36) 1.98 (1.27–2.66) 2(1.23) 145(89.51) 15(9.26) # VA 0.073 Deficiency 17 (1.30) 1.57 (1.18–2.42) 1(5.88) 16(94.12) 0(0.00) Marginal deficiency 129 (9.84) 1.71 (1.24–2.46) 2(1.55) 124(96.12) 3(2.33) Sufficiency 1165 (88.86) 1.91 (1.34–2.65) 27(2.32) 1057(90.73) 81(6.95) VD 0.580 Deficiency 78 (5.95) 2.14 (1.50–2.88) c 1(1.28) 72(92.31) 5(6.41) Insufficiency 340 (25.93) 2.09 (1.47–2.81) d 6(1.76) 307(90.29) 27(7.94) Sufficiency 893 (68.12) 1.80 (1.26–2.50) 23(2.58) 818(91.60) 52(5.82) UIC(µg/L) 0.409 < 100 332 (29.35) 1.80 (1.31–2.36) 7(2.11) 309(93.07) 16(4.82) 100~ 361 (31.91) 1.81 (1.26–2.56) 5(1.39) 338(92.35) 23(6.28) 150~ 251 (22.19) 1.94 (1.44–2.73) 7(2.78) 224(88.89) 21(8.33) 200~ 176 (13.42) 2.04 (1.36–2.86) 7(3.98) 154 (87.50) 15 (8.52) 250~ 114 (8.70) 2.08 (1.37–2.85) 3(2.63) 103(90.35) 8(7.02) ≥ 300 71 (5.42) 1.99 (1.25–2.53) 1(1.41) 69(97.18) 1(1.41) Total 1311 (100) 1.89 (1.32–2.59) 30(2.29) 1197(91.30) 84(6.41) UIC: urinary iodine concentration, TSH: thyroid-stimulating hormone, BMI: body mass index, VA: vitamin A, VD: vitamin D a : Hebei vs. Zhejiang; b : Hebei vs. Guangxi; c, : deficiency vs. sufficiency; d : insufficiency vs. sufficiency; # : group differences. Statistical significance was considered when P < 0.05. Relationship between Thyroid-stimulating Hormone and Urinary Iodine under Different Vitamin A or Vitamin D Nutritional Status The same methods as Table 5 were used to analyze the linear relationship between TSH and UIC, VA/VD nutritional status. Results showed that lnTSH was not correlated to UIC and VA/VD concentrations ( P > 0.05). And the nutritional status of UI, VA and VD was also not related to TSH with or without adjusting the confounders region, area type, age and BMI ( P > 0.05), neither(data not shown). To reflect the relationship between UIC and TSH under different vitamin A/D nutritional conditions, which could further describe the relationship among the three parameters, we analyzed the effects of iodine nutritional status on TSH levels under different VA or VD nutritional status. We found that there were no statistical differences among all groups, and the median TSH in each group was within the normal range (Fig. 1 a and 1 b). Moreover, VA/VD status did not affect TSH distributions in each UIC group ( P > 0.05) (Fig. 1 c and 1 d). Discussion As IDD is still a globally public health problem, evaluating iodine nutritional status of population remains important. 24 hours of urinary iodine excretion (24-h UIE) is considered as the most reliable measurement for assessing iodine intake, but it is difficult to obtain 24-h urine sample in our large-scale epidemiological study. Another indicator, urinary iodine to creatinine ratio (UI/Cr), approximates the value of 24-h UIE and minimizes the UIC variations caused by differences in urine volume and dilution. But creatinine secretion can be affected by many factors, including race, gender and age [ 19 ]. The MUIC of spot urine sample is recommended by the UNICEF as an indicator for assessing population iodine status [ 17 ], and is widely used in children [ 20 ], adults [ 21 ], pregnant [ 22 ] and lactating women [ 23 ]. Therefore, we analyzed the iodine nutritional status of the mothers with MUIC in this study. According to the 2018 Guidance on the Monitoring of Salt Iodization Programmes and Determination of Population Iodine Status, a MUIC in the range of 100–299 µg/L identifies a population that has no iodine deficiency[ 17 ].And as the World Health Organization (WHO)/ United Nations International Children’s Emergency Fund (UNICEF)/International Council for Control of Iodine Deficiency Disorders (ICCIDD) Guide for Programme Managers recommends, not more than 20% of samples in the population having no iodine deficiency should be < 50 µg/L [ 18 ]. The median UIC (MUIC) (P 25 -P 75 ) of total mothers and mothers in lactation was 142.00 µg/L (99.10-209.40 µg/L) and 139.95 µg/L (96.22-208.03) µg/L, respectively.The iodine status was optimal but much lower than the lactating women in suitable water iodine content areas in Shanxi Province (283.6 µg/L) [ 24 ]. And there was no UI difference between breastfeeding mothers and non-breastfeeding mothers. Moreover, 25.32% of mothers showed UICs < 100 µg/L in the surveyed areas, while only 5.03% of mothers had UIC < 50 µg/L. These results were close to a study for lactating women in Guangxi, which showed appropriate MUIC (130 µg/L) and high proportion of UIC 300 µg/L, and the rate was relatively low. Thus, we need to pay more attention to mothers with lower UICs. Since geographic influences on the iodine status existed in pregnant and lactating women, neonates, and school-age children [ 26 , 27 ], and geographic locations with poor iodine status were suggested to identify [ 17 ], we then analyzed UIC differences among the three representative provinces. Our previous study concluded that the iodine nutritional status of school-age children varied among Hebei, Zhejiang and Guangxi, and lower MUIC and higher proportion of UIC < 100 µg/L was observed in Hebei and Zhejiang [ 9 ]. Similar to school children, the MUIC of mothers in Zhejiang was the lowest and the proportion of UIC < 100 µg/L in Zhejiang was the highest. But the MUIC in Hebei was the highest. We supposed the geographical difference of iodine nutritional status between children and mothers might be due to the different nutrients requirements and actual intakes. Besides, in the three provinces, we also found that the MUIC of rural mothers was higher than that of urban mothers, consistent with a previous study of paticipants ≥ 0 years old from Zhejiang Province [ 28 ]. We guess that dietary patterns, lifestyles and iodised salt intake may be the major factors which influence the iodine nutritional status for rural and urban mothers. As UIC was shown to be positively related to age among children, and prevalence of UIC < 100 µg/L was the highest among the youngest children, which might be related to lower iodine intake [ 9 ], we then analyzed the effect of age on UIC among mothers. In this study, UIC was not statistically significant among the agegroups, but we also found that the younger group was more prone to having UIC < 50 µg/L. It was consistent with a study on lactating women from Taiwan, suggesting that iodine deficiency may continue to be present in those pregnant at younger ages as they were less wealthy to take enough iodine [ 29 ]. However, studies on the relationship between UIC and age are limited, so further studies are warranted. In addition, studies have proved that iodine deficiency is associated with dyslipidemia and obesity. And iodine deficiency can accelerate lipolysis and fatty acid oxidation, and increase plasma TSH level without affecting thyroid hormone signal [ 30 ]. Our previous study on school-age children has also confirmed this phenomenon [ 9 ]. But obese mothers in this study showed higher MUIC, which was consistent with a Mexican study conducted in children from primary schools, finding a positive correlation between UIC values and BMI, and the prevalence of overweight and obesity [ 31 ]. It might be related to more dietary iodine intake in overweight and obese population. However, at present only few discordant studies have analyzed the relationship of UIC and BMI in children, but not in breastfeeding or nonbreastfeeding mothers. In general, the tendency of UIC in different region, age and BMI was different between school-age children and mothers, which might be related to the difference of iodine demand, digestion, absorption and metabolism between the two populations. Thus, further studies are needed to better understand the impact of demographic characteristics on UIC. In addition, it is important to note that mothers’ requirements of VA and VD intake are increased during the breastfeeding period. And higher retinol concentrations could be observed in maternal blood and the umbilical cord of newborns with a higher VA intake by mothers [ 32 ]. Generally, energy, macronutrients and some micronutrients intake of lactating women in China can reach or exceed recommended levels, but the intake of VD is difficult to meet the requirement [ 33 ]. The 2010–2013 China Health and Nutrition Survey (CHNS) reported that the average VA of lactating mothers was 1.56 ± 0.39 µmol/L (0.45 ± 0.11µg/mL), and the prevalence of VA deficiency and marginal deficiency were 0.5% and 7.8%, respectively [ 34 ], which was close to that in our study. However, VD deficiency and insufficiency remained a serious problem among mothers in our study, though it was better than the 2013 results, which showed a high prevalence of VD deficiency (25.2%) and VD insufficiency (45.4%) among lactating mothers [ 35 ]. To better analyze the iodine status, we took VA and VD into account. Similar to UIC, VA and VD also showed geographical differences. VA and MUIC in Zhejiang were the highest, while VD levels and proportion of UIC < 100 µg/L in Hebei were the lowest, suggesting that there might be an association among UIC, VA and VD. Similar to our previous study performed in children [ 9 ], mothers with sufficient VA tended to have higher MUIC, while VD deficient mothers were not likely to have UIC < 100 µg/L. We also found lnUIC was positively correlated with VA (with or without adjusting for confounders) and negatively related to VD (with or without adjusting for confounders) in this study population. But VA/VD status had no effects on UICs while adjusting for these confounders, which needs to be further verified by expanding the sample size. TSH, another biomarker of classifying iodine status of population [ 36 ], was also measured in this study. More than 90% of mothers were within the normal range. Hebei had the highest TSH concentration, and TSH distribution was related to BMI. VA had been proved to inhibit TSH secretion and synthesis [ 37 ] and TSH could be inversely influenced by VD as VD plays important roles in the pathogenesis of thyroid autoimmunity [ 38 ]. Studies had also shown interactions of VA/VD and iodine deficiency on thyroid function [ 12 , 39 ]. Then we analyzed whether TSH levels could be influenced by UIC, VA and VD status. Among lactating women, we found TSH concentration was higher in VD deficiency group, though VA/VD nutritional status was not found to affect the distribution of TSH. Moreover, after adjusting for confounding factors, the existed associations between TSH and VD disappeared. Notably, inconsistent conclusions on the relationship between TSH and UIC were presented. For example, a ‘U curve’ relationship between TSH and UIC had been reported in children [ 40 ]. In this study, no typical U-shaped relationship between TSH and UIC was observed, but an “approximately inverted” U-shaped relationship between TSH and UIC was found, similar to data from other studies from Liu, L. et al. and Meng, F. et al. [ 25 , 40 ], though non-linear correlation between TSH and UIC of lactating women was observed. We speculated that it might be related to the large proportion of TSH in the normal range. And more studies are needed draw this conclusion. In addition, VA/VD nutritional status did not affect TSH distribution in each UIC group, which deserves further verification. Above all, we thoroughly assessed the iodine nutritional status of mothers with children under 2 years old by using indicators including MUIC and TSH. We analyzed the possible impact of region, area type, age, BMI and whether in lactation on iodine nutrition. VA and VD, as important nutrients for health, were taken into account as well. We even considered the influence of confounding factors when analyzing the association between UIC (or TSH) and vitamins. However, Several limitations of this study should be noted: i) The data of lactating ways were not detailed enough, which made it difficult to analyze the difference between complete breastfeeding and mixed breastfeeding mothers. ii) Other indicators such as free thyroxine (fT4), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) were not detected due to the limited blood samples available; iii) We didn’t evaluate the consistency of dietary iodine and urinary iodine due to lack of detailed dietary iodine data. Therefor, in the future, we should observe urinary and breast iodine concentration, even 24-h UIE, in different postpartum periods and breastfeeding ways dynamically and continuously, and master the mechanisms of iodine metabolism during lactation to provide the basis for proper iodine supplementation in lactating women or mothers with children < 2 years old. In summary, iodine intake was overall adequate in mothers in the studied areas. But enhanced monitoring of iodine status by more suitable measures is warranted. Moreover, UIC or TSH was notably associated with region, age, BMI, VA, or VD. These findings provide an important basis for better iodine nutritional evaluation and surveillance in China in the future. Abbreviations UIC urinary iodine concentration MUIC median UIC TSH thyroid-stimulating hormone BMI body mass index VA vitamin A VD vitamin D IDD iodine deficiency disorders VAD Vitamin A deficiency VDD vitamin D deficiency CDC Center for Disease Control and Prevention. Declarations Acknowledgments We would like to thank all the participants in this study and the staff working for the 2016 National Nutrition and Health Surveillance of Children and Lactating Women. Author ’s Contributions Yang L. contributed to the study’s conception and design. Material preparation and data collection were performed by Zou Y., Huang L., Jiang S., Zhou W., Qin Q., Liu C., Luo X., Lu J., Mao D., Li M. and Yang Z. Data analysis and the first draft of the manuscript was written by Shan X. All authors have read and agreed to the published version of the manuscript. Funding This research was funded by National Health Commission of People’s Republic of China Medical Reform Major Program ‘2016-2017 National Nutrition and Health Surveillance of Children and Lactating Women’, and Major Public Health Project ‘Survey and Evaluation of Iodine Nutrition and Thyroid Diseases of Chinese Population’ (131031107000160007). Availability of data and materials The datasets generated during the current study are not publicly available due to privacy considerations but are available from the corresponding author on reasonable request. Ethics Approval and Consent to Participate Approval was obtained from the Ethics Review Committee of Chinese Center for Disease Control and Prevention (201614, 3 June 2016). The procedures used in this study adhere to the tenets of the Declaration of Helsinki. Informed consent was obtained from all individual participants included in the study. Consent for publication Not applicable Competing interests The authors declare that they have no conflict of interest. Ethics Approval and Consent to Participate Approval was obtained from the Ethics Review Committee of Chinese Center for Disease Control and Prevention (201614, 3 June 2016). The procedures used in this study adhere to the tenets of the Declaration of Helsinki. Informed consent was obtained from all individual participants included in the study. References Zimmermann MB (2011) The role of iodine in human growth and development. Seminars in cell & developmental biology 22:645–652 Aakre I, Bjoro T, Norheim I, Strand TA, Barikmo I, Henjum S (2015) Excessive iodine intake and thyroid dysfunction among lactating Saharawi women. J Trace Elem Med Biol 31:279–284 Ristic-Medic D, Dullemeijer C, Tepsic J, Petrovic-Oggiano G, Popovic T, Arsic A, Glibetic M, Souverein OW, Collings R, Cavelaars A, de Groot L, van't Veer P, Gurinovic M (2014) Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups. Nutr Rev 72:143–161 Ding Y, Indayati W, Basnet TB, Li F, Wang Z (2020) Dietary intake in lactating mothers in China 2018: report of a survey. Nutrition Journal 19 Liao M, Liu J, Ning R, Lu H, Luo Y, Wang F (2020) Investigation of Iodine Nutrition Status and Thyroid Function of Lactating Women in Guangxi. Acta Nutrimenta Sinica 42:99–101 Yang J, Zhu L, Li X, Zheng H, Wang Z, Hao Z, Liu Y (2017) Maternal iodine status during lactation and infant weight and length in Henan Province, China. BMC Pregnancy Childbirth 17:383 Sun D, Lei Z, Liu S (2017) The Monitoring of Iodine Deficiency Disorders of China in 2014. People’s Medical Publishing House: Beijing, China Cui SL, Liu P, Su XH, Liu Sh J (2017) Surveys in Areas of High Risk of Iodine Deficiency and Iodine Excess in China, 2012–2014: Current Status and Examination of the Relationship between Urinary Iodine Concentration and Goiter Prevalence in Children Aged 8–10 Years. Biomedical and environmental sciences: BES 30:88–96 Shan X, Liu C, Luo X, Zou Y, Huang L, Zhou W, Qin Q, Mao D, Li M, Yang L (2021) Iodine Nutritional Status and Related Factors among Chinese School-Age Children in Three Different Areas: A Cross-Sectional Study. Nutrients 13 Zimmermann (2007) Interactions of Vitamin A and Iodine Deficiencies: Effects on the Pituitary-Thyroid Axis. International Journal for Vitamin and Nutrition Research 77:236–240 Hungria S, Sena X, Marques YL (2020) NUTRITIONAL DEFICIENCIES AND HYPOTHYROIDISM. Kim M, Song E, Oh HS, Park S, Kwon H, Jeon MJ, Kim WG, Kim WB, Shong YK, Kim TY (2017) Vitamin D deficiency affects thyroid autoimmunity and dysfunction in iodine-replete area: Korea national health and nutrition examination survey. Endocrine 58:332–339 Lu Z (2020) Comparison of lactating women vitamin levels and folic acid level in urban and rural areas of Nanjing. Lab Med Clin 17:1480–1482, 1486 Jiang S, Wang J, Duan Y, Pang X, Bi Y, Zhang H, Wang S, Lai J, Yang Z (2021) Prevalence and risk factors for anemia of Chinese lactating women in 2013. Wei Sheng Yan Jiu 50:716–721 China Eccomntooaoi (2016) Consensus Statement of the Chinese Medical and Nutritional Experts on Management for Overweight/obesity in China (2016). Chin J Diabetes Mellitus:525–540 Consultation WE (2004) Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet (London, England) 363:157–163 UNICEF (2018) Guidance on the Monitoring of Salt Iodization Programmes and Determination of Population Iodine Status. WHO, UNICEF, ICCIDD (2007) Assessment of Iodine Deficiency Disorders and Monitoring their Elimination: a Guide for Programme Managers, 3rd ed. Haddow JE, McClain MR, Palomaki GE, Hollowell JG (2007) Urine iodine measurements, creatinine adjustment, and thyroid deficiency in an adult United States population. J Clin Endocrinol Metab 92:1019–1022 Xiu L, Zhong G, Ma X (2017) Urinary iodine concentration (UIC) could be a promising biomarker for predicting goiter among school-age children: A systematic review and meta-analysis. PloS one 12:e0174095 Pearce EN, Caldwell KL (2016) Urinary iodine, thyroid function, and thyroglobulin as biomarkers of iodine status. Am J Clin Nutr 104 Suppl 3:898S-901S Yang L, Li M, Liu X, Wu M, Zhang J, Zhao L, Ding G, Yang X (2020) Evaluation of Iodine Nutritional Status Among Pregnant Women in China. Thyroid: official journal of the American Thyroid Association 30:443–450 Nazeri P, Mirmiran P, Shiva N, Mehrabi Y, Mojarrad M, Azizi F (2015) Iodine nutrition status in lactating mothers residing in countries with mandatory and voluntary iodine fortification programs: an updated systematic review. Thyroid 25:611–620 Liu L, Liu J, Wang D, Shen H, Jia Q (2020) Effect of Urinary Iodine Concentration in Pregnant and Lactating Women, and in Their Infants Residing in Areas with Excessive Iodine in Drinking Water in Shanxi Province, China. Biological trace element research 193:326–333 Liu L, Wang D, Liu P, Meng F, Wen D, Jia Q, Liu J, Zhang X, Jiang P, Shen H (2015) The relationship between iodine nutrition and thyroid disease in lactating women with different iodine intakes. British Journal of Nutrition 114:1487–1495 Wang D, Wan S, Liu P, Meng F, Liu L (2021) Relationship between excess iodine, thyroid function, blood pressure, and blood glucose level in adults, pregnant women, and lactating women: A cross-sectional study. Ecotoxicology and Environmental Safety 208:111706 Lou X, Wang X, Mao G, Zhu W, Mo Z, Wang Y, Wang Z (2020) Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China. Nutr J 19:7 Zou Y, Lou X, Ding G, Mo Z, Zhu W, Mao G (2014) A cross-sectional comparison study on the iodine nutritional status between rural and urban residents in Zhejiang Province, China. BMJ Open 4:e005484 Huang CJ, Cheng CP, Lee LH, Chen HS, Hwu CM, Tang KT, Shih CW, Yeh CC, Yang CC, Wang FF (2021) Iodine nutritional status of lactating women in northern Taiwan in 2019. J Chin Med Assoc 84:400–404 Bocco B, Fernandes GW, Fonseca TL, Bianco AC (2020) Iodine Deficiency Increases Fat Contribution to Energy Expenditure in Male Mice. Endocrinology:12 García-Solís P, Solís SJ, García-Gaytán AC, Reyes-Mendoza VA, Robles-Osorio L, Villarreal-Ríos E, Leal-García L, Hernández-Montiel HL (2013) Iodine nutrition in elementary state schools of Queretaro, Mexico: correlations between urinary iodine concentration with global nutrition status and social gap index. Arquivos brasileiros de endocrinologia e metabologia 57:473–482 Pablo G-S, Olga PG, Carlos ES-L, Gabriela H-P, Hebert LH-M, Juan CS-S (2018) Thyroid hormones and obesity: a known but poorly understood relationship. Endokrynologia Polska 69:282–303 Dong CX, Yin SA (2016) The nutrition status of lactating women in China. Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 50:1108–1113 Wang J (2020) Monitoring Report on Nutrition and Health Status of Chinese Residents (2010–2013): Nutrition and Health Status of Pregnant Women and Lactating Mothers in China. Pang XH, Yang ZY, Wang J, Duan YF, Zhao LY, Yin SA, Lai JQ (2016) [Nutritional status and influence of vitamin D among Chinese lactating women in 2013]. Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 50:1056–1060 Wassie MM, Middleton P, SJ Z (2019) Agreement between markers of population iodine status in classifying iodine status of populations: a systematic review. Am J Clin Nutr 110:949–958 Ceresini G, Rebecchi I, Morganti S, Maggio M, Solerte SB, Corcione L, Izzo S, Mecocci P, Valenti G (2002) Effects of vitamin A administration on serum thyrotropin concentrations in healthy human subjects. Metabolism Clinical & Experimental 51:691–694 De RA, Tomei G, Maria LF, Occhuzzi U, Rapino D (2016) Inverse relationship between seasonal vitamin D variations and thyroid antibodies (TAb) and TSH. Endocrine Abstracts Zimmermann (2007) Interactions of vitamin A and iodine deficiencies: effects on the pituitary-thyroid axis. Int J Vitam Nutr Res 77:236–240 Meng F, Zhao R, Liu P, Liu L, Liu S (2013) Assessment of iodine status in children, adults, pregnant women and lactating women in iodine-replete areas of China. PLoS One 8:e81294 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1485512","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":94462006,"identity":"ebb6ec6d-1e60-4fd0-bcfe-8e418146d34e","order_by":0,"name":"Xiaoyun Shan","email":"","orcid":"","institution":"National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Key Laboratory of Trace Element Nutrition, National Health Commission of the People’s Republic of 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Yang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7UlEQVRIiWNgGAWjYLCCBww2DGwMPAwMjA0SIL4BYS0JDGmkazkMJMFaGAhrMTh+9vCLhJrzeXzSvQcYfu6wyONvP7zxA0PNHdxazuSlWSQcu13MJnMugbH3jESxxJm0YgmGY89wazmQY2aQ2HA7sU0ix4CZsU0iseEGjxnQhYdxazn/BqTlHELLfIJabuQYP0hsOIDQsoGQFskbb8wYEo4lg7Uc7AVq2QjyS8Ix3Fr4zucYf/hQY5c4f0aO4YOfbXWJ844DQ+xDDW4tCgcY2CRgnANw4QScGhgY5BsYmD/gkR8Fo2AUjIJRwMAAAFBzWcceWoPfAAAAAElFTkSuQmCC","orcid":"","institution":"National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Key Laboratory of Trace Element Nutrition, National Health Commission of the People’s Republic of China","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Lichen","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2022-03-24 12:44:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1485512/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1485512/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":19833781,"identity":"a14855d1-098a-40ad-975b-21c08ec79f22","added_by":"auto","created_at":"2022-03-31 18:30:10","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":111032,"visible":true,"origin":"","legend":"\u003cp\u003eConcentrations and distribution of TSH in each UIC group under different VA/VD status.\u003c/p\u003e","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1485512/v1/d90600ad195046698acbf785.jpg"},{"id":19944668,"identity":"954a2fe8-4e1e-4226-b46b-1613750680e3","added_by":"auto","created_at":"2022-04-04 17:29:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":639198,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1485512/v1/eb0724eb-1df3-4716-ab9e-fb15c29a6d96.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Iodine Nutrition and Related Factors of Mothers with Children under 2 Years Old from Three Different Areas in China: A Cross-sectional Survey","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIodine is an essential trace element for the synthesis of thyroid hormones. And iodine status is particularly important for pregnant and lactating women, since iodine deficiency disorders (IDD) affects fetuses in utero and infants through breastfeeding, which may lead to impaired neurological development [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. On the other hand, high prevalence of thyroid dysfunction caused by iodine excess, has also become a problem over the past years [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Therefore, adequate iodine nutrition is critical for susceptible populations including pregnant and lactating women as well as infants, who have higher iodine demand. In addition, as mothers with children under 2 years old in China have the dual heavy pressure of breastfeeding and returning to work, it is also very important to ensure appropriate iodine and other nutrients.\u003c/p\u003e \u003cp\u003eIodine is mainly obtained from diet. A systematic review indicated that the doubling of dietary iodine intake could increase urinary iodine concentrations (UICs) in different populations [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. A recent survey from 13 provinces and municipalities in China showed that the dietary iodine intake of lactating women was much lower than the recommended levels [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], but two studies from Guangxi and Henan Province in China demonstrated that the median UICs (MUICs) of lactating women were both at the appropriate levels [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. This phenomenon suggests that the overall iodine nutritional status may not represent the regional situation. Therefore, it is necessary to analyze the iodine nutritional status in areas with different geographical characteristics. According to the 2014 monitoring data of IDD in China, the overall level of urinary iodine in the eastern region was lower than that in the central and western regions [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. As Hebei, Zhejiang, Guangxi in eastern China were historically areas with cretinism and low iodized-salt coverage rates [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], we previously assessed the iodine nutritional status among school-age children in the three representative provinces, which showed that lower MUIC and higher proportion of \u0026lt;\u0026thinsp;100 \u0026micro;g/L was observed in Hebei and Zhejiang, compared to Guangxi [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. So similar study is warranted among mothers with children under 2 years old.\u003c/p\u003e \u003cp\u003eVitamin A (VA) deficiency (VAD), vitamin D (VD) deficiency (VDD) and IDD often coexist in vulnerable groups, such as lactating women. As VAD has multiple effects on the pituitary-thyroid axis, studies indicated that concurrent VA supplementation with iodized salt could improve iodine efficacy in IDD- and VAD-affected children [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. VD can also act in the immune system, and its deficiency is associated with Hashimoto\u0026rsquo;s thyroiditis [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. For example, a significant association between VDD and high prevalence of thyroid autoimmunity and dysfunction in participants with excessive iodine intake was found in the Korean population [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. And our previous study showed the iodine nutritional status of children and adolescents was related to VA and VD [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. It is also necessary to analyze the relationship between iodine nutritional status and VA/VD in mothers with children under 2 years old.\u003c/p\u003e \u003cp\u003eAt present, few studies about the relationships between iodine nutrition and other factors (including vitamins, region, age and body mass index (BMI)) were carried out on lactating women, especially on mothers with children under 2 years old. Therefore, this study intended to study the iodine status of mothers with children under 2 years old and analyze its related factors, so as to provide reference for iodine nutrition monitoring of mothers and their newborns.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003eStudy Regions and Subjects\u003c/h2\u003e\n \u003cp\u003eThe data were collected from the 2016\u0026ndash;2017 National Nutrition and Health Surveillance of Children and Lactating Women, a large-scale cross-sectional survey. Three provinces in eastern China including Hebei Province in the north, Guangxi Province in the south, and Zhejiang Province in the east coast were selected. Mothers with children under 2 years old were investigated and sampled [\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]. Inclusion criteria were: i) having been breastfeeding after this delivery; ii) no chronic diseases; iii) no thyroid disease or usage of thyroid drugs. Subjects were selected by using the multi-stage stratified cluster randomization sampling method. The national sample size was calculated according to the anemia rate of lactating mothers in 2013. The formula was as follows:\u003c/p\u003e\n \u003cp\u003e\u003cimg 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\u003cp\u003eN, number of samples; Deff (design effect)\u0026thinsp;=\u0026thinsp;2.0; p (anemia rate)\u0026thinsp;=\u0026thinsp;9.3%; r (relative standard error)\u0026thinsp;=\u0026thinsp;11%; The confidence level ((bilateral) was 95%, then u\u0026thinsp;=\u0026thinsp;1.96. There were four types of areas (large cities, small cities, ordinary rural areas and poor rural areas), and the nonresponse rate was 10%. The sample size was about 27500 (covering 275 districts or counties ). Moreover, according to the proportion (32.9%) of UIC\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L among lactating women in Guangxi, the calculated sample size was 314 [\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e]. Then 100 participants were included in each district or county. Four types of areas were chosed from each district or county. And at least 25 mothers were randomly selected from each type of area. At last, 1500 mothers were included in the three province (containing 5 districts or counties in each province, with non-high water iodine). Participants with missing anthropometric indexes or missing UIC, thyroid-stimulating hormone (TSH), VA and VD measurements, were excluded. Participants with other missing pertinent covariates were also excluded. The data from 1311 participants were ultimately included in the present analysis. Written informed consent was obtained from all individual participants included in the study. This study was approved by the Ethical Review Committee of Center for Disease Control and Prevention (CDC), and all the documentations and procedures complied with the ethical standards of the committee.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec4\"\u003e\n \u003ch2\u003eAnthropometric Measurements and Chemical Analyses\u003c/h2\u003e\n \u003cp\u003eInquiry survey, anthropometric measurement, blood and urine samples collection were intensively performed in the community or village.\u003c/p\u003e\n \u003cp\u003eHeight in cm and weight in kg were measured directly by trained interviewers who followed standard protocols similar to the National Health and Nutrition Examination Survey (NHANES) protocol. Height and weight were measured to the nearest 0.1 cm and 0.1 kg respectively without shoes and wearing light clothing only. BMI was calculated in kg divided by height in square meters (kg/m\u003csup\u003e2\u003c/sup\u003e). .\u003c/p\u003e\n \u003cp\u003eBlood and urine samples were analyzed in laboratories at the provincial level. All laboratories should have passed the examination of the National Reference Laboratory, China CDC. A random spot midstream urine sample was collected in the morning from 08:30 to 12:00 (approximately 8\u0026ndash;10 mL) from all participants. After collection, urine samples were stored in polyethylene plastic tubes and sealed tightly to prevent evaporation. Samples should avoid contact with iodized articles during transportation and be stored at \u0026minus;\u0026thinsp;20 ℃ until analysis. UIC was measured using arsenic and cerium catalysis spectrophotometry after digestion in ammonium sulfate solution (WS/T 107.1\u0026ndash;2016). Blood samples (6 mL) were collected from the cubital vein of the mothers and stored in gel vacuum collective tubes. Blood samples were centrifuged at 3000 rpm for 10 minutes at room temperature as soon as possible.The serum was then stored in a frozen plastic tube made of 99.9% biological grade polypropylene. If not tested immediately, the serum samples were subsequently frozen at \u0026minus;\u0026thinsp;80℃ until analysis. TSH levels were determined using an automated chemiluminescence immunoassay analyzer (Roche, German). High-performance liquid chromatography was used to determine the serum retinol concentration (WS/T 553\u0026ndash;2017). The VD (25(OH)D) level was determined using liquid chromatography-mass spectrometry (WS/T 677\u0026ndash;2020)..\u003c/p\u003e\n \u003cp\u003eAll the reference ranges of the included parameters are shown in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e:\u0026nbsp;\u003c/p\u003e\u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eReference range of related parameters\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eParameter\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReference range\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eIdentification\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBMI [\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;18.5\u0026thinsp; kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e18.5\u0026ndash;23.9\u0026thinsp; kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e24.0-27.9\u0026thinsp; kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;28 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUnderweight\u003c/p\u003e\n \u003cp\u003eNormal range\u003c/p\u003e\n \u003cp\u003eOverweight\u003c/p\u003e\n \u003cp\u003eObese\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMUIC [\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u0026ndash;299 \u0026micro;g/L and proportion of \u0026lt;\u0026thinsp;50 \u0026micro;g/L was \u0026le; 20%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAdequate iodine intake\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTSH (Roche Kit)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.27\u0026ndash;4.20 mIU/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNormal range\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.2 \u0026micro;g/mL\u003c/p\u003e\n \u003cp\u003e0.2\u0026ndash;0.3 \u0026micro;g/mL\u003c/p\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;0.3 \u0026micro;g/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDeficiency\u003c/p\u003e\n \u003cp\u003eMarginal deficiency\u003c/p\u003e\n \u003cp\u003eSufficiency\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;30 nmol/L (12ng/mL)\u003c/p\u003e\n \u003cp\u003e30\u0026ndash;50 nmol/L (12\u0026ndash;20 ng/mL)\u003c/p\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;50 nmol/L (20 ng/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDeficiency\u003c/p\u003e\n \u003cp\u003eInsufficiency\u003c/p\u003e\n \u003cp\u003eSufficiency\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\"\u003eMUIC: median urinary iodine concentration, TSH: thyroid-stimulating hormone, BMI: body mass index, VA: vitamin A, VD: vitamin D\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec5\"\u003e\n \u003ch2\u003eStatistical Analysis\u003c/h2\u003e\n \u003cp\u003eData processing and statistical analyses were carried out using IBM SPSS Statistics 23. Kolmogorov\u0026ndash;Smirnov (KS) test was used for normality test. If the indicator was not normally distributed, it was expressed as median and P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e. 95% confidence interval (CI) of UIC was also used to test whether statistical difference existed between relevant cut-off point (100 \u0026micro;g/L) and the MUIC, just as the 2018 Guidance on the Monitoring of Salt Iodization Programmes and Determination of Population Iodine Status recommended [\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. Nonparametric statistical test was used to compare age, BMI, UIC, TSH, VA or VD differences among the groups (region, area type, lactation, age, BMI, VA or VD groups ). A two-way ANOVA model was performed to analyze the interaction effect. The chi-square test was used to compare the difference of categorical variables. As UIC and TSH showed skewed distribution, they were ransitioned with ln. Then simple linear regression and multiple linear regression were used to analyze the linear relationship between VA, VD and lnUIC as well as lnTSH. The generalized linear model of the relationship between UIC, TSH and possible factors (VA and VD) was established. Potential confounders, including area type, age (continuous), and BMI (continuous) were introduced as covariates in the adjusted models. Data were considered statistically significant at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eDescription of the Population\u003c/h2\u003e \u003cp\u003eCharacteristics of the participants are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The median age and BMI of the participants were 30.04(P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e: 27.15\u0026ndash;34.23)years and 22.78 (P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e: 20.65\u0026ndash;25.41) kg/m\u003csup\u003e2\u003c/sup\u003e, respectively. BMI in Hebei was higher than that of the other two provinces (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). More than half of the mothers had the second child, and 68.34% of mothers were still breastfeeding at that moment.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of Chinese mothers from three different regions (median, P\u003csub\u003e25\u003c/sub\u003e\u0026ndash;P\u003csub\u003e75\u003c/sub\u003e)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHebei (n\u0026thinsp;=\u0026thinsp;493)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eZhejiang (n\u0026thinsp;=\u0026thinsp;429)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGuangxi (n\u0026thinsp;=\u0026thinsp;389)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTotal (n\u0026thinsp;=\u0026thinsp;1311)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRural (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e289(60.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e244(56.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e172(44.22)\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e714(54.46)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of children (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e185(37.53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e170(39.63)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e119(30.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e474(36.16)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e293(59.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e247(57.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e239(61.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e779(59.42)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15(3.04)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12(2.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e31(7.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e58(4.42)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIn lactation (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e382(77.48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e262(61.07)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e252(64.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e896(68.34)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e111(22.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e167(38.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e137(35.22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e415(31.66)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30.00 (27.00\u0026ndash;33.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e31.07 (28.19\u0026ndash;35.94) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30.25 (26.99\u0026ndash;33.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30.04 (27.15\u0026ndash;34.23)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI(kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23.82 (21.61\u0026ndash;26.31) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22.29 (20.44\u0026ndash;24.92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22.03 (20.17\u0026ndash;24.51)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e22.78 (20.65\u0026ndash;25.41)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eBMI: body mass index, *: Compared with the other two provinces, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eUrinary Iodine, Thyroid-stimulating Hormone, Vitamin A and Vitamin D Levels in the Three Provinces\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e showed the levels and differences of parameters among the three provinces. Median serum UIC, TSH, retinol and 25(OH)D levels of the total population were all in the normal ranges. UIC (Median: 166.10, P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e: 116.25-228.95, \u0026micro;g/L) and TSH (Median: 2.11, P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e: 1.48\u0026ndash;2.87, mIU/L) in Hebei were the highest (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), while 25(OH)D (Median: 17.20, P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e: 13.70-21.82, ng/mL) levels was the lowest (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), with an average level less than 20 ng/mL. Moreover, UIC and retinol were different from each other province (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eParameters of Chinese mothers from three different regions (Median, P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHebei (n\u0026thinsp;=\u0026thinsp;493)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eZhejiang (n\u0026thinsp;=\u0026thinsp;429)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGuangxi (n\u0026thinsp;=\u0026thinsp;389)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTotal (n\u0026thinsp;=\u0026thinsp;1311)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUIC(\u0026micro;g/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e166.10 (116.25-228.95) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e123.58 (86.42-185.04) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e139.40 (90.80-206.15) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e142.00 (99.10-209.40)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTSH (mIU/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.11 (1.48\u0026ndash;2.87) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.72 (1.21\u0026ndash;2.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.86 (1.24\u0026ndash;2.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.89 (1.32\u0026ndash;2.59)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRetinol (\u0026micro;g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.43 (0.37\u0026ndash;0.54) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.36 (0.30\u0026ndash;0.45) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.51 (0.44\u0026ndash;0.59) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.44 (0.36\u0026ndash;0.53)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25 (OH) D (ng/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17.20 (13.70-21.82) \u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.26 (23.39\u0026ndash;34.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26.40 (23.40\u0026ndash;30.20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e24.04 (18.20\u0026ndash;29.00)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eUIC: urinary iodine concentration, TSH: thyroid-stimulating hormone. *: Compared with the other two provinces, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eUrinary Iodine Concentrations and Distributions\u003c/h2\u003e \u003cp\u003eAs shown in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, the MUIC of total mothers and mothers in lactation was 142.00 (95% CI: 40.74-358.97) \u0026micro;g/L and 139.95 (96.22-208.03) \u0026micro;g/L, respectively. No significant differences in UI were found between breastfeeding mothers and non-breastfeeding mothers. And only 5.42% of mothers showed UIC\u0026thinsp;\u0026ge;\u0026thinsp;300 \u0026micro;g/L. The proportion of UIC values\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L was 25.32%, while only 5.03% of mothers had UIC\u0026thinsp;\u0026lt;\u0026thinsp;50 \u0026micro;g/L. The mothers in the three provinces all had no iodine deficiency. Zhejiang had the lowest UIC and highest rate of \u0026lt;\u0026thinsp;50 \u0026micro;g/L (123.58 \u0026micro;g/L and 6.99% respectively, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), while Hebei was in the opposite. And the MUIC in the rural was higher than that in the urban (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). As differences in the proportion of urban and rural population existed among the three provinces, we further analyzed whether the relationship between region and UIC was affected by area type by a two-way ANOVA model. Results showed that there was interaction effect between region and area type (data not shown). Although more mothers in 18\u0026thinsp;~\u0026thinsp;years group were showing UIC\u0026thinsp;\u0026lt;\u0026thinsp;50 \u0026micro;g/L (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), there was no significant difference in UIC among different age groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). The MUIC was the highest among the obese mothers (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). There was no significant difference in UI concentrations and distributions among different VA status (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05), but the UIC seemed to be lower in VA deficiency group. On the contrary, the MUIC in VD deficiency group was the highest, and more mothers in the VD deficiency group showed UIC between 100\u0026ndash;299 \u0026micro;g/L (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMedian and frequency distributions of UIC among Chinese mothers\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFactors\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMUIC, 95%CI (\u0026micro;g/L)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c8\" namest=\"c4\"\u003e \u003cp\u003eFrequency Distribution (%) Per UIC Range, \u0026micro;g/L\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;50\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e50~\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e100~\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e\u0026ge;\u0026thinsp;300\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003eP\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRegion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHebei\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e493 (37.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e166.10 (48.88-336.18) \u003csup\u003ea, b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13(2.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e64(12.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385(78.09) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e31(6.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZhejiang\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e429 (32.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e123.58 (32.41-399.95) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30(6.99)\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e115(26.81) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e270(62.94)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e14(3.26) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGuangxi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e389 (29.67)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e139.40 (39.48-419.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23(5.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e87(22.37)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e253(65.04)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e26(6.68)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eArea type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRural\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e714 (54.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e159.80 (46.54-377.42)\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23(3.22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e130(18.21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e517(72.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e44(6.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrban\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e597 (45.54)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e125.30 (34.03-342.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e43(7.20)\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e136(22.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e391(65.49)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e27(4.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIn lactation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.309\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e896 (68.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e139.95 (96.22-208.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e46(5.13)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e194 (21.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e607 (67.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e49 (5.47)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e415 (31.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e148.69(104.40-211.80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20(4.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e72 (17.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e301 (72.53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e22 (5.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.012\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e129 (9.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e142.00 (33.28-411.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14(10.85) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e28(21.71)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e78(60.47)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e9(6.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e883 (67.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e146.00 (38.32-355.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e45(5.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e175(19.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e620(70.22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e43(4.87)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e299 (22.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e136.13 (49.69-368.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7(2.3.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e63(21.07)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e210(70.23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e19(6.35)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.387\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnderweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e89 (6.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e152.14 (34.78-478.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6(6.74) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e20(18.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e56(62.92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e7(7.87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNormal weight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e725 (55.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e140.90 (37.56-405.25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e39(5.38)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e144(19.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e501(69.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e41(5.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOverweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e335 (25.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e131.30 (44.37-355.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14(4.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e77(22.99)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e232(69.25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e12(7.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObesity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e162 (12.36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e169.55 (43.22-335.92) \u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7(4.32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e25(15.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e119(73.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e11(6.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.567\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17 (1.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e119.34 (66.98-249.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0(0.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5(31.25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e11(68.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0(0.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMarginal deficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e129 (9.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e140.02 (30.60-497.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8(6.20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e27(20.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e86(66.67)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e8(6.20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1165 (88.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e142.40 (40.88-355.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e58(4.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e234(20.09)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e810(69.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e63(5.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.036\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78 (5.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e175.10 (41.48\u0026ndash;341.40) \u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2(2.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8(10.26) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e63(80.77) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5(6.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e340 (25.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e159.30 (42.22-329.64) \u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16(4.71)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e57(16.76)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e247(72.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20(5.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e893 (68.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e133.86 (37.49-389.36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e48(5.37)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e201(22.51) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e598(66.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e46(5.15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1311 (100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e142.00(40.74-358.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e66(5.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e266(20.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e908(69.26)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e71(5.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eMUIC: median urinary iodine concentration, TSH: thyroid-stimulating hormone, BMI: body mass index, VA: vitamin A, VD: vitamin D. a: Hebei vs. Zhejiang; b: Hebei vs. Guangxi; c,: Zhejiang vs Guangxi;d: Rural vs. Urban; e: Overweight vs. Obesity; f: deficiency vs. sufficiency༛g: insufficiency vs sufficiency; \u003csup\u003e\u003cb\u003e#\u003c/b\u003e\u003c/sup\u003e: group differences. Statistical significance was considered when \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eRelationship between Urinary Iodine Concentration and Vitamin A/Vitamin D Nutritional Status\u003c/h2\u003e \u003cp\u003eConsidering that whether mothers were in lactation had no influence on UIC and UIC distribution, we took all mothers as a whole for the following analysis. Simple linear regression analysis showed that lnUIC was positively correlated with total VA (β\u0026thinsp;=\u0026thinsp;0.095, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0. 014), but negatively correlated with total VD (β=- 0.007, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.000). After adjusting for variables including area type, age and BMI, lnUIC was still positively correlated with total VA (β\u0026thinsp;=\u0026thinsp;0.127, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0. 001) and total VD (β=- 0.007, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0. 000). However, generalized linear model analysis indicated that UIC were not correlated with the nutritional status of VA after stratification, with or without adjusting for the covariates (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). UICs in VD insufficient group and deficient group were higher than that in sufficient group (β\u003csub\u003einsufficiency\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;15.503, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0. 005; β\u003csub\u003edeficiency\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;26.999, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0. 008) when the covariates were not adjusted. After adjusting for the variables of area type, age and BMI, UIC was no longer related to VD nutritional status (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAssociation between lnUIC or UIC and VA/VD nutritional status\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFactors\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003elnUIC or UIC\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eβ (95% CI)\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eSE\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003eP\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVA-Model 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.095 (0.019\u0026thinsp;~\u0026thinsp;0.170)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.038\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.014\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-21.243 (-62.504\u0026thinsp;~\u0026thinsp;20.018)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21.052\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.313\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMarginal deficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.949 (-13.723\u0026thinsp;~\u0026thinsp;17.621)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.996\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.807\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVA-Model 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.127 (0.052\u0026thinsp;~\u0026thinsp;0.203)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.039\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-10.306 (-51.434\u0026thinsp;~\u0026thinsp;30.822)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.623\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMarginal deficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.770 (-10.346\u0026thinsp;~\u0026thinsp;21.885)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.222\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.483\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVD-Model 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.007(-0.011~-0.003)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.999 (7.149\u0026thinsp;~\u0026thinsp;46.849)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.128\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.503 (4.789\u0026thinsp;~\u0026thinsp;26.216)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.466\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.005\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVD-Model 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.007 (-0.010~-0.003)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.901 (-13.600\u0026thinsp;~\u0026thinsp;29.403)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.970\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.471\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.981 (-10.533\u0026thinsp;~\u0026thinsp;14.496)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6.385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.756\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eUIC: urinary iodine concentration, VA: vitamin A, VD: vitamin D. Model 1: unadjusted;Model 2༚adjusted for area type, age and BMI. *: Regression analysis between total VA or VD and lnUIC. Statistical significance was considered when \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eThyroid-stimulating Hormone Concentrations and Distributions\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e showed that the median TSH of the mothers was within the reference range, and the overall TSH exceeding rate was only 6.41%. There were no significant differences in TSH among different area type, age, VA and UIC groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). TSH level in Hebei (Median: 2.11 mIU/L) was the highest. In addition, we found that BMI was associated with the distribution of TSH, and overweight and obese mothers had the highest excessive rate of TSH (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Moreover, TSHs in VD deficiency group and insufficiency group were higher than that in sufficiency group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). But no typical U-shaped relationship between TSH and UIC was observed.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTSH concentrations and distributions among mothers in the three provinces\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFactors\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMedian (P\u003csub\u003e25\u003c/sub\u003e\u0026ndash;P\u003csub\u003e75\u003c/sub\u003e), mIU/L\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c7\" namest=\"c4\"\u003e \u003cp\u003eFrequency Distribution (%) Per TSH Range, mIU/L\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.27\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.27\u0026ndash;4.20\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026ge;\u0026thinsp;4.20\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003eP\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRegion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.072\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHebei\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e493 (37.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.11(148\u0026thinsp;\u0026minus;\u0026thinsp;2.87) \u003csup\u003ea, b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13(2.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e437(88.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e43(8.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZhejiang\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e429 (32.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.72 (1.21\u0026ndash;2.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11(2.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e397(92.54)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e21(4.90)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGuangxi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e389 (29.67)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.86 (1.24\u0026ndash;2.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6(1.54)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e363(93.32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e20(5.14)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eArea type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.053\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRural\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e714 (54.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.89 (1.32\u0026ndash;2.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e18(2.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e640(89.64)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e56(7.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrban\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e597(45.54)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.89( 1.32\u0026ndash;2.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12(2.01)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e557(93.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e28(4.69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.910\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e129 (9.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.88 (1.30\u0026ndash;2.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3(2.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e117(90.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e9(6.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e883 (67.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.86 (1.31\u0026ndash;2.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19(2.15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e805(91.17)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e59(6.68)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e299 (22.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.96 (1.41\u0026ndash;2.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8(2.68)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e275(91.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e16(5.35)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnderweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e89 (6.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.07 (1.31\u0026ndash;2.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0(0.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e88(98.88) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1(1.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNormal weight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e725 (55.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.86 (1.32\u0026ndash;2.53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16(2.21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e672(92.69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e37(5.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOverweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e335 (25.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.92 (1.31\u0026ndash;2.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12(3.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e292(87.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e31(9.25) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eobesity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e162 (12.36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.98 (1.27\u0026ndash;2.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2(1.23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e145(89.51)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e15(9.26) \u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.073\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17 (1.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.57 (1.18\u0026ndash;2.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1(5.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16(94.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0(0.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMarginal deficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e129 (9.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.71 (1.24\u0026ndash;2.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2(1.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e124(96.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3(2.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1165 (88.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.91 (1.34\u0026ndash;2.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e27(2.32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1057(90.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e81(6.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.580\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78 (5.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.14 (1.50\u0026ndash;2.88) \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1(1.28)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e72(92.31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5(6.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e340 (25.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.09 (1.47\u0026ndash;2.81) \u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6(1.76)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e307(90.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e27(7.94)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e893 (68.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.80 (1.26\u0026ndash;2.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23(2.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e818(91.60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e52(5.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUIC(\u0026micro;g/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.409\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e332 (29.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.80 (1.31\u0026ndash;2.36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7(2.11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e309(93.07)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e16(4.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e100~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e361 (31.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.81 (1.26\u0026ndash;2.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5(1.39)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e338(92.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e23(6.28)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e150~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e251 (22.19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.94 (1.44\u0026ndash;2.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7(2.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e224(88.89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e21(8.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e200~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e176 (13.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.04 (1.36\u0026ndash;2.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7(3.98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e154 (87.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e15 (8.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e250~\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e114 (8.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.08 (1.37\u0026ndash;2.85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3(2.63)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e103(90.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e8(7.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e71 (5.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.99 (1.25\u0026ndash;2.53)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1(1.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e69(97.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1(1.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1311 (100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.89 (1.32\u0026ndash;2.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30(2.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1197(91.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e84(6.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eUIC: urinary iodine concentration, TSH: thyroid-stimulating hormone, BMI: body mass index, VA: vitamin A, VD: vitamin D\u003csup\u003ea\u003c/sup\u003e: Hebei vs. Zhejiang; \u003csup\u003eb\u003c/sup\u003e: Hebei vs. Guangxi; \u003csup\u003ec,\u003c/sup\u003e: deficiency vs. sufficiency; \u003csup\u003ed\u003c/sup\u003e : insufficiency vs. sufficiency; \u003csup\u003e#\u003c/sup\u003e: group differences. Statistical significance was considered when \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eRelationship between Thyroid-stimulating Hormone and Urinary Iodine under Different Vitamin A or Vitamin D Nutritional Status\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe same methods as Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e were used to analyze the linear relationship between TSH and UIC, VA/VD nutritional status. Results showed that lnTSH was not correlated to UIC and VA/VD concentrations (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). And the nutritional status of UI, VA and VD was also not related to TSH with or without adjusting the confounders region, area type, age and BMI (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05), neither(data not shown).\u003c/p\u003e \u003cp\u003eTo reflect the relationship between UIC and TSH under different vitamin A/D nutritional conditions, which could further describe the relationship among the three parameters, we analyzed the effects of iodine nutritional status on TSH levels under different VA or VD nutritional status. We found that there were no statistical differences among all groups, and the median TSH in each group was within the normal range (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). Moreover, VA/VD status did not affect TSH distributions in each UIC group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eAs IDD is still a globally public health problem, evaluating iodine nutritional status of population remains important. 24 hours of urinary iodine excretion (24-h UIE) is considered as the most reliable measurement for assessing iodine intake, but it is difficult to obtain 24-h urine sample in our large-scale epidemiological study. Another indicator, urinary iodine to creatinine ratio (UI/Cr), approximates the value of 24-h UIE and minimizes the UIC variations caused by differences in urine volume and dilution. But creatinine secretion can be affected by many factors, including race, gender and age [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The MUIC of spot urine sample is recommended by the UNICEF as an indicator for assessing population iodine status [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], and is widely used in children [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], adults [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], pregnant [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] and lactating women [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Therefore, we analyzed the iodine nutritional status of the mothers with MUIC in this study.\u003c/p\u003e \u003cp\u003eAccording to the 2018 Guidance on the Monitoring of Salt Iodization Programmes and Determination of Population Iodine Status, a MUIC in the range of 100\u0026ndash;299 \u0026micro;g/L identifies a population that has no iodine deficiency[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].And as the World Health Organization (WHO)/ United Nations International Children\u0026rsquo;s Emergency Fund (UNICEF)/International Council for Control of Iodine Deficiency Disorders (ICCIDD) Guide for Programme Managers recommends, not more than 20% of samples in the population having no iodine deficiency should be \u0026lt;\u0026thinsp;50 \u0026micro;g/L [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The median UIC (MUIC) (P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e) of total mothers and mothers in lactation was 142.00 \u0026micro;g/L (99.10-209.40 \u0026micro;g/L) and 139.95 \u0026micro;g/L (96.22-208.03) \u0026micro;g/L, respectively.The iodine status was optimal but much lower than the lactating women in suitable water iodine content areas in Shanxi Province (283.6 \u0026micro;g/L) [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. And there was no UI difference between breastfeeding mothers and non-breastfeeding mothers. Moreover, 25.32% of mothers showed UICs\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L in the surveyed areas, while only 5.03% of mothers had UIC\u0026thinsp;\u0026lt;\u0026thinsp;50 \u0026micro;g/L. These results were close to a study for lactating women in Guangxi, which showed appropriate MUIC (130 \u0026micro;g/L) and high proportion of UIC\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L (32.9%) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. As excessive iodine intake potentially causes subclinical hypothyroidism in lactating women [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], we additionally analyzed the proportion of UIC values\u0026thinsp;\u0026gt;\u0026thinsp;300 \u0026micro;g/L, and the rate was relatively low. Thus, we need to pay more attention to mothers with lower UICs.\u003c/p\u003e \u003cp\u003eSince geographic influences on the iodine status existed in pregnant and lactating women, neonates, and school-age children [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], and geographic locations with poor iodine status were suggested to identify [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], we then analyzed UIC differences among the three representative provinces. Our previous study concluded that the iodine nutritional status of school-age children varied among Hebei, Zhejiang and Guangxi, and lower MUIC and higher proportion of UIC \u0026lt; 100 \u0026micro;g/L was observed in Hebei and Zhejiang [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Similar to school children, the MUIC of mothers in Zhejiang was the lowest and the proportion of UIC\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L in Zhejiang was the highest. But the MUIC in Hebei was the highest. We supposed the geographical difference of iodine nutritional status between children and mothers might be due to the different nutrients requirements and actual intakes. Besides, in the three provinces, we also found that the MUIC of rural mothers was higher than that of urban mothers, consistent with a previous study of paticipants\u0026thinsp;\u0026ge;\u0026thinsp;0 years old from Zhejiang Province [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. We guess that dietary patterns, lifestyles and iodised salt intake may be the major factors which influence the iodine nutritional status for rural and urban mothers. As UIC was shown to be positively related to age among children, and prevalence of UIC\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L was the highest among the youngest children, which might be related to lower iodine intake [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], we then analyzed the effect of age on UIC among mothers. In this study, UIC was not statistically significant among the agegroups, but we also found that the younger group was more prone to having UIC\u0026thinsp;\u0026lt;\u0026thinsp;50 \u0026micro;g/L. It was consistent with a study on lactating women from Taiwan, suggesting that iodine deficiency may continue to be present in those pregnant at younger ages as they were less wealthy to take enough iodine [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. However, studies on the relationship between UIC and age are limited, so further studies are warranted. In addition, studies have proved that iodine deficiency is associated with dyslipidemia and obesity. And iodine deficiency can accelerate lipolysis and fatty acid oxidation, and increase plasma TSH level without affecting thyroid hormone signal [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Our previous study on school-age children has also confirmed this phenomenon [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. But obese mothers in this study showed higher MUIC, which was consistent with a Mexican study conducted in children from primary schools, finding a positive correlation between UIC values and BMI, and the prevalence of overweight and obesity [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. It might be related to more dietary iodine intake in overweight and obese population. However, at present only few discordant studies have analyzed the relationship of UIC and BMI in children, but not in breastfeeding or nonbreastfeeding mothers. In general, the tendency of UIC in different region, age and BMI was different between school-age children and mothers, which might be related to the difference of iodine demand, digestion, absorption and metabolism between the two populations. Thus, further studies are needed to better understand the impact of demographic characteristics on UIC.\u003c/p\u003e \u003cp\u003eIn addition, it is important to note that mothers\u0026rsquo; requirements of VA and VD intake are increased during the breastfeeding period. And higher retinol concentrations could be observed in maternal blood and the umbilical cord of newborns with a higher VA intake by mothers [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Generally, energy, macronutrients and some micronutrients intake of lactating women in China can reach or exceed recommended levels, but the intake of VD is difficult to meet the requirement [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The 2010\u0026ndash;2013 China Health and Nutrition Survey (CHNS) reported that the average VA of lactating mothers was 1.56\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39 \u0026micro;mol/L (0.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u0026micro;g/mL), and the prevalence of VA deficiency and marginal deficiency were 0.5% and 7.8%, respectively [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e], which was close to that in our study. However, VD deficiency and insufficiency remained a serious problem among mothers in our study, though it was better than the 2013 results, which showed a high prevalence of VD deficiency (25.2%) and VD insufficiency (45.4%) among lactating mothers [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. To better analyze the iodine status, we took VA and VD into account. Similar to UIC, VA and VD also showed geographical differences. VA and MUIC in Zhejiang were the highest, while VD levels and proportion of UIC\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L in Hebei were the lowest, suggesting that there might be an association among UIC, VA and VD. Similar to our previous study performed in children [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], mothers with sufficient VA tended to have higher MUIC, while VD deficient mothers were not likely to have UIC\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;g/L. We also found lnUIC was positively correlated with VA (with or without adjusting for confounders) and negatively related to VD (with or without adjusting for confounders) in this study population. But VA/VD status had no effects on UICs while adjusting for these confounders, which needs to be further verified by expanding the sample size.\u003c/p\u003e \u003cp\u003eTSH, another biomarker of classifying iodine status of population [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e], was also measured in this study. More than 90% of mothers were within the normal range. Hebei had the highest TSH concentration, and TSH distribution was related to BMI. VA had been proved to inhibit TSH secretion and synthesis [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] and TSH could be inversely influenced by VD as VD plays important roles in the pathogenesis of thyroid autoimmunity [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Studies had also shown interactions of VA/VD and iodine deficiency on thyroid function [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Then we analyzed whether TSH levels could be influenced by UIC, VA and VD status. Among lactating women, we found TSH concentration was higher in VD deficiency group, though VA/VD nutritional status was not found to affect the distribution of TSH. Moreover, after adjusting for confounding factors, the existed associations between TSH and VD disappeared. Notably, inconsistent conclusions on the relationship between TSH and UIC were presented. For example, a \u0026lsquo;U curve\u0026rsquo; relationship between TSH and UIC had been reported in children [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. In this study, no typical U-shaped relationship between TSH and UIC was observed, but an \u0026ldquo;approximately inverted\u0026rdquo; U-shaped relationship between TSH and UIC was found, similar to data from other studies from Liu, L. et al. and Meng, F. et al. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], though non-linear correlation between TSH and UIC of lactating women was observed. We speculated that it might be related to the large proportion of TSH in the normal range. And more studies are needed draw this conclusion. In addition, VA/VD nutritional status did not affect TSH distribution in each UIC group, which deserves further verification.\u003c/p\u003e \u003cp\u003eAbove all, we thoroughly assessed the iodine nutritional status of mothers with children under 2 years old by using indicators including MUIC and TSH. We analyzed the possible impact of region, area type, age, BMI and whether in lactation on iodine nutrition. VA and VD, as important nutrients for health, were taken into account as well. We even considered the influence of confounding factors when analyzing the association between UIC (or TSH) and vitamins. However, Several limitations of this study should be noted: i) The data of lactating ways were not detailed enough, which made it difficult to analyze the difference between complete breastfeeding and mixed breastfeeding mothers. ii) Other indicators such as free thyroxine (fT4), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) were not detected due to the limited blood samples available; iii) We didn\u0026rsquo;t evaluate the consistency of dietary iodine and urinary iodine due to lack of detailed dietary iodine data. Therefor, in the future, we should observe urinary and breast iodine concentration, even 24-h UIE, in different postpartum periods and breastfeeding ways dynamically and continuously, and master the mechanisms of iodine metabolism during lactation to provide the basis for proper iodine supplementation in lactating women or mothers with children\u0026thinsp;\u0026lt;\u0026thinsp;2 years old.\u003c/p\u003e \u003cp\u003eIn summary, iodine intake was overall adequate in mothers in the studied areas. But enhanced monitoring of iodine status by more suitable measures is warranted. Moreover, UIC or TSH was notably associated with region, age, BMI, VA, or VD. These findings provide an important basis for better iodine nutritional evaluation and surveillance in China in the future.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eUIC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eurinary iodine concentration\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMUIC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003emedian UIC\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTSH\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethyroid-stimulating hormone\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ebody mass index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eVA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003evitamin A\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eVD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003evitamin D\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIDD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eiodine deficiency disorders\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eVAD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eVitamin A deficiency\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eVDD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003evitamin D deficiency\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCDC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCenter for Disease Control and Prevention.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank all the participants in this study and the staff working for the 2016 National Nutrition and Health Surveillance of Children and Lactating Women.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor\u003c/strong\u003e\u003cstrong\u003e\u0026rsquo;s\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYang L.\u0026nbsp;contributed to the study\u0026rsquo;s conception and design. Material preparation and data collection were performed by Zou Y., Huang\u0026nbsp;L.,\u0026nbsp;Jiang\u0026nbsp;S.,\u0026nbsp;Zhou\u0026nbsp;W.,\u0026nbsp;Qin\u0026nbsp;Q.,\u0026nbsp;Liu\u0026nbsp;C.,\u0026nbsp;Luo\u0026nbsp;X.,\u0026nbsp;Lu\u0026nbsp;J.,\u0026nbsp;Mao\u0026nbsp;D.,\u0026nbsp;Li\u0026nbsp;M. and\u0026nbsp;Yang\u0026nbsp;Z. Data analysis and the first draft of the manuscript was written by\u0026nbsp;Shan X. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was funded by\u0026nbsp;National Health Commission of People\u0026rsquo;s Republic of China Medical Reform Major Program\u0026nbsp;\u0026lsquo;2016-2017\u0026nbsp;National Nutrition and Health Surveillance of Children and Lactating Women\u0026rsquo;, and Major Public Health Project \u0026lsquo;Survey and Evaluation of Iodine Nutrition and Thyroid Diseases of Chinese Population\u0026rsquo; (131031107000160007).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during the current study are not publicly available due to privacy considerations but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent to Participate\u0026nbsp;\u003c/strong\u003eApproval was obtained from the Ethics Review Committee of Chinese Center for Disease Control and Prevention (201614, 3 June 2016).\u0026nbsp;The procedures used in this study adhere\u0026nbsp;to the tenets of the Declaration of Helsinki.\u0026nbsp;Informed consent was obtained from all individual participants included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of\u0026nbsp;interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent to Participate\u0026nbsp;\u003c/strong\u003eApproval was obtained from the Ethics Review Committee of Chinese Center for Disease Control and Prevention (201614, 3 June 2016). The procedures used in this study adhere to the tenets of the Declaration of Helsinki. Informed consent was obtained from all individual participants included in the study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZimmermann MB (2011) The role of iodine in human growth and development. Seminars in cell \u0026amp; developmental biology 22:645\u0026ndash;652\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAakre I, Bjoro T, Norheim I, Strand TA, Barikmo I, Henjum S (2015) Excessive iodine intake and thyroid dysfunction among lactating Saharawi women. J Trace Elem Med Biol 31:279\u0026ndash;284\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRistic-Medic D, Dullemeijer C, Tepsic J, Petrovic-Oggiano G, Popovic T, Arsic A, Glibetic M, Souverein OW, Collings R, Cavelaars A, de Groot L, van't Veer P, Gurinovic M (2014) Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups. Nutr Rev 72:143\u0026ndash;161\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDing Y, Indayati W, Basnet TB, Li F, Wang Z (2020) Dietary intake in lactating mothers in China 2018: report of a survey. Nutrition Journal 19\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiao M, Liu J, Ning R, Lu H, Luo Y, Wang F (2020) Investigation of Iodine Nutrition Status and Thyroid Function of Lactating Women in Guangxi. Acta Nutrimenta Sinica 42:99\u0026ndash;101\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang J, Zhu L, Li X, Zheng H, Wang Z, Hao Z, Liu Y (2017) Maternal iodine status during lactation and infant weight and length in Henan Province, China. BMC Pregnancy Childbirth 17:383\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun D, Lei Z, Liu S (2017) The Monitoring of Iodine Deficiency Disorders of China in 2014. People\u0026rsquo;s Medical Publishing House: Beijing, China\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCui SL, Liu P, Su XH, Liu Sh J (2017) Surveys in Areas of High Risk of Iodine Deficiency and Iodine Excess in China, 2012\u0026ndash;2014: Current Status and Examination of the Relationship between Urinary Iodine Concentration and Goiter Prevalence in Children Aged 8\u0026ndash;10 Years. Biomedical and environmental sciences: BES 30:88\u0026ndash;96\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShan X, Liu C, Luo X, Zou Y, Huang L, Zhou W, Qin Q, Mao D, Li M, Yang L (2021) Iodine Nutritional Status and Related Factors among Chinese School-Age Children in Three Different Areas: A Cross-Sectional Study. Nutrients 13\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZimmermann (2007) Interactions of Vitamin A and Iodine Deficiencies: Effects on the Pituitary-Thyroid Axis. International Journal for Vitamin and Nutrition Research 77:236\u0026ndash;240\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHungria S, Sena X, Marques YL (2020) NUTRITIONAL DEFICIENCIES AND HYPOTHYROIDISM.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim M, Song E, Oh HS, Park S, Kwon H, Jeon MJ, Kim WG, Kim WB, Shong YK, Kim TY (2017) Vitamin D deficiency affects thyroid autoimmunity and dysfunction in iodine-replete area: Korea national health and nutrition examination survey. Endocrine 58:332\u0026ndash;339\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLu Z (2020) Comparison of lactating women vitamin levels and folic acid level in urban and rural areas of Nanjing. Lab Med Clin 17:1480\u0026ndash;1482, 1486\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang S, Wang J, Duan Y, Pang X, Bi Y, Zhang H, Wang S, Lai J, Yang Z (2021) Prevalence and risk factors for anemia of Chinese lactating women in 2013. Wei Sheng Yan Jiu 50:716\u0026ndash;721\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChina Eccomntooaoi (2016) Consensus Statement of the Chinese Medical and Nutritional Experts on Management for Overweight/obesity in China (2016). Chin J Diabetes Mellitus:525\u0026ndash;540\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eConsultation WE (2004) Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet (London, England) 363:157\u0026ndash;163\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUNICEF (2018) Guidance on the Monitoring of Salt Iodization Programmes and Determination of Population Iodine Status.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWHO, UNICEF, ICCIDD (2007) Assessment of Iodine Deficiency Disorders and Monitoring their Elimination: a Guide for Programme Managers, 3rd ed.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaddow JE, McClain MR, Palomaki GE, Hollowell JG (2007) Urine iodine measurements, creatinine adjustment, and thyroid deficiency in an adult United States population. J Clin Endocrinol Metab 92:1019\u0026ndash;1022\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXiu L, Zhong G, Ma X (2017) Urinary iodine concentration (UIC) could be a promising biomarker for predicting goiter among school-age children: A systematic review and meta-analysis. PloS one 12:e0174095\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePearce EN, Caldwell KL (2016) Urinary iodine, thyroid function, and thyroglobulin as biomarkers of iodine status. Am J Clin Nutr 104 Suppl 3:898S-901S\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang L, Li M, Liu X, Wu M, Zhang J, Zhao L, Ding G, Yang X (2020) Evaluation of Iodine Nutritional Status Among Pregnant Women in China. Thyroid: official journal of the American Thyroid Association 30:443\u0026ndash;450\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNazeri P, Mirmiran P, Shiva N, Mehrabi Y, Mojarrad M, Azizi F (2015) Iodine nutrition status in lactating mothers residing in countries with mandatory and voluntary iodine fortification programs: an updated systematic review. Thyroid 25:611\u0026ndash;620\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu L, Liu J, Wang D, Shen H, Jia Q (2020) Effect of Urinary Iodine Concentration in Pregnant and Lactating Women, and in Their Infants Residing in Areas with Excessive Iodine in Drinking Water in Shanxi Province, China. Biological trace element research 193:326\u0026ndash;333\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu L, Wang D, Liu P, Meng F, Wen D, Jia Q, Liu J, Zhang X, Jiang P, Shen H (2015) The relationship between iodine nutrition and thyroid disease in lactating women with different iodine intakes. British Journal of Nutrition 114:1487\u0026ndash;1495\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang D, Wan S, Liu P, Meng F, Liu L (2021) Relationship between excess iodine, thyroid function, blood pressure, and blood glucose level in adults, pregnant women, and lactating women: A cross-sectional study. Ecotoxicology and Environmental Safety 208:111706\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLou X, Wang X, Mao G, Zhu W, Mo Z, Wang Y, Wang Z (2020) Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China. Nutr J 19:7\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZou Y, Lou X, Ding G, Mo Z, Zhu W, Mao G (2014) A cross-sectional comparison study on the iodine nutritional status between rural and urban residents in Zhejiang Province, China. BMJ Open 4:e005484\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang CJ, Cheng CP, Lee LH, Chen HS, Hwu CM, Tang KT, Shih CW, Yeh CC, Yang CC, Wang FF (2021) Iodine nutritional status of lactating women in northern Taiwan in 2019. J Chin Med Assoc 84:400\u0026ndash;404\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBocco B, Fernandes GW, Fonseca TL, Bianco AC (2020) Iodine Deficiency Increases Fat Contribution to Energy Expenditure in Male Mice. Endocrinology:12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarc\u0026iacute;a-Sol\u0026iacute;s P, Sol\u0026iacute;s SJ, Garc\u0026iacute;a-Gayt\u0026aacute;n AC, Reyes-Mendoza VA, Robles-Osorio L, Villarreal-R\u0026iacute;os E, Leal-Garc\u0026iacute;a L, Hern\u0026aacute;ndez-Montiel HL (2013) Iodine nutrition in elementary state schools of Queretaro, Mexico: correlations between urinary iodine concentration with global nutrition status and social gap index. Arquivos brasileiros de endocrinologia e metabologia 57:473\u0026ndash;482\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePablo G-S, Olga PG, Carlos ES-L, Gabriela H-P, Hebert LH-M, Juan CS-S (2018) Thyroid hormones and obesity: a known but poorly understood relationship. Endokrynologia Polska 69:282\u0026ndash;303\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDong CX, Yin SA (2016) The nutrition status of lactating women in China. Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 50:1108\u0026ndash;1113\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang J (2020) Monitoring Report on Nutrition and Health Status of Chinese Residents (2010\u0026ndash;2013): Nutrition and Health Status of Pregnant Women and Lactating Mothers in China.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePang XH, Yang ZY, Wang J, Duan YF, Zhao LY, Yin SA, Lai JQ (2016) [Nutritional status and influence of vitamin D among Chinese lactating women in 2013]. Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 50:1056\u0026ndash;1060\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWassie MM, Middleton P, SJ Z (2019) Agreement between markers of population iodine status in classifying iodine status of populations: a systematic review. Am J Clin Nutr 110:949\u0026ndash;958\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCeresini G, Rebecchi I, Morganti S, Maggio M, Solerte SB, Corcione L, Izzo S, Mecocci P, Valenti G (2002) Effects of vitamin A administration on serum thyrotropin concentrations in healthy human subjects. Metabolism Clinical \u0026amp; Experimental 51:691\u0026ndash;694\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe RA, Tomei G, Maria LF, Occhuzzi U, Rapino D (2016) Inverse relationship between seasonal vitamin D variations and thyroid antibodies (TAb) and TSH. Endocrine Abstracts\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZimmermann (2007) Interactions of vitamin A and iodine deficiencies: effects on the pituitary-thyroid axis. Int J Vitam Nutr Res 77:236\u0026ndash;240\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeng F, Zhao R, Liu P, Liu L, Liu S (2013) Assessment of iodine status in children, adults, pregnant women and lactating women in iodine-replete areas of China. PLoS One 8:e81294\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Median urinary iodine concentration, Thyroid-stimulating hormone, Vitamin A, Vitamin D, Mothers with children under 2 years old","lastPublishedDoi":"10.21203/rs.3.rs-1485512/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1485512/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTo analyze the iodine nutritional status and related factors of mothers with children under 2 years old, we collected data from the 2016\u0026ndash;2017 National Nutrition and Health Surveillance of Children and Lactating Women. A total of 1311 mothers from Hebei, Zhejiang, and Guangxi province were included in the study. Urinary iodine concentration (UIC), thyroid-stimulating hormone (TSH), body mass index (BMI), vitamin A (VA), and vitamin D (VD) were measured. The distributions of UIC and TSH were assessed. Relationships between UIC, TSH and the possible factors were analyzed. The median UIC (MUIC) (P\u003csub\u003e25\u003c/sub\u003e-P\u003csub\u003e75\u003c/sub\u003e) of total mothers and mothers in lactation was 142.00 \u0026micro;g/L (99.10-209.40 \u0026micro;g/L) and 139.95 \u0026micro;g/L (96.22-208.03) \u0026micro;g/L, respectively. No differences in UI were found between breastfeeding mothers and non-breastfeeding mothers. The prevalence of mothers with UICs\u0026thinsp;\u0026lt;\u0026thinsp;50\u0026micro;g/L was 5.03%, and 91.30% of mothers showed TSH normality. UICs and UIC distributions were significantly different among the three provinces, and between rural and urban areas. Obese mothers tended to have higher MUIC and higher prevalence of excessive TSH. Linear correlations between lnUIC and VA/VD were observed with or without adjusting for confounding factors. Higher TSHs were observed in both VD deficiency and insufficiency groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). However, typical U-shaped relationship between TSH and UIC was not observed in this population. In conclusion, Mothers in our study had no iodine deficiency, but numbers of mothers were still having a UIC of \u0026lt;\u0026thinsp;100 \u0026micro;g/L or \u0026gt;\u0026thinsp;300 \u0026micro;g/L. Region, area type, age, BMI, VA, or VD should be taken into consideration in the future iodine evaluation and surveillance.\u003c/p\u003e","manuscriptTitle":"Iodine Nutrition and Related Factors of Mothers with Children under 2 Years Old from Three Different Areas in China: A Cross-sectional Survey","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-03-31 18:30:08","doi":"10.21203/rs.3.rs-1485512/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"35b81477-0dfb-47b1-a3f3-5aa69d524a16","owner":[],"postedDate":"March 31st, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-04-04T17:29:20+00:00","versionOfRecord":[],"versionCreatedAt":"2022-03-31 18:30:08","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1485512","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1485512","identity":"rs-1485512","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}