Associations between Soft drinks intake and Primary Dysmenorrhea: A Cross-sectional Study among Chinese undergraduate female students

Associations between Soft drinks intake and Primary Dysmenorrhea: A Cross-sectional Study among Chinese undergraduate female students | 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 Article Associations between Soft drinks intake and Primary Dysmenorrhea: A Cross-sectional Study among Chinese undergraduate female students Lijiao Wang, Lingyan Qiao, Shuo Wen, Xinyuan Li, Ahiafor Maxwell, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4389961/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Sep, 2024 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Background Primary dysmenorrhea (PD) is a common global health concern. However, limited studies explored the association between soft drinks intake and PD among female undergraduates in China. Objective To determine the association between soft drinks (carbonated soft drinks, etc.) as well coffee intake and the incidence/severity of PD among female undergraduates in China. Methods We performed a cross-sectional study among 1809 female undergraduates in China from September 29, 2020 to October 22, 2020. The demographic information and menstrual information of the participants were collected by a self-administrated questionnaire. Chi-square test, ANOVA test, and logistic regression test were used to investigate the association between soft drinks intake and the incidence/severity of PD. We also conducted stratification analysis among different locations ( rural or urban). Results The prevalence of PD was 47.1% (n = 852). There were 221 (25.9%) participants suffered from severe pain. In the participants with PD, the OR of carbonated soft drinks intake was 1.244 (95% CI = 1.010–1.533). Among the participants with PD from rural areas, the OR of carbonated soft drinks intake was 1.402 (95% CI = 1.045–1.881), compared with the non-carbonated soft drink group. In the participants with moderate and severe PD, the OR of coffee intake was 0.451 (95% CI = 0.228–0.892), compared with the non-coffee-drinking group. There was a significant association between carbonated soft drinks intake frequency and the severity of PD (P < 0.05). Conclusion Our study showed that carbonated soft drinks intake is a risk factor for PD, especially in participants from rural areas. Coffee intake is a protective factor for the severity of PD. Periodical awareness programs about adverse effects of excessive soft drink consumption should be introduced to reduce the prevalence and exacerbation of PD. Coffee intake might be helpful to relieve the severity of PD. Health sciences/Health care Health sciences/Medical research Primary dysmenorrhea Female undergraduates Soft drinks intake Figures Figure 1 INTRODUCTION Soft drinks include soda water, syrup, or other carbonated or non-carbonated beverages [ 1 ]. Also known sometimes as carbonated beverages or sodas, soft drinks are non-alcoholic beverages that are typically carbonated and flavored. Coffee is considered a beverage that is brewed from roasted coffee beans [ 2 ]. One of the primary ingredients in soft drinks is sugar, with an average content 100 g/L [ 3 ]. The global consumption of soft drinks has increased dramatically over the past several decades with the greatest increase among young people [ 4 ]. While the exact amount differs from study to study, they all indicate that soft drink consumption has been on the rise in China in recent years [ 5 ], resulting in a remarkably increase in various health conditions and diseases. Similarly, coffee consumption which was considered a western lifestyle, has significantly gained popularity in China, a country with long history of drinking green tea. The demand for coffee has also grown rapidly in recent years [ 6 ]. Statistical reports show that Chinese population consumed around 4.8 million 60-kilogram bags of coffee, as coffee production volume in China amounted to around 1.8 million bags in the same period. Although considered a beverage, coffee has a stimulant effect on the human nervous system due to it’s caffeine content [ 7 ]. Notable of these effects are ; caffeine in coffee possess an antagonistic effect on adenosine A1 and A2A receptors, causing hyperexcitability of the central nervous system [ 8 ], also affects physical stamina, cognitive function and in some cases amplify symptoms of anxiety [ 9 ]. Primary dysmenorrhea(PD)is defined as painful menstruation in absence of pelvic pathological changes, characterized by recurrent, cramp-like lower abdominal pain during menstruation [ 10 , 11 ]. It doubles as the most common gynecologic condition and one of the most common causes of pelvic pain in pre-menopausal women [ 10 , 12 , 13 ]. The prevalence of PD among female university students varies widely, ranging from 45–95% [ 14 ]. Though not a life-threatening condition, PD can cause substantial burden on the quality of life [ 11 , 15 ]. In the United States, about 600 million work hours and 2 billion dollars annual economic loss has been attributed to PD [ 16 ]. In Japan, it has been reported that the total healthcare cost for patients with PD is 2.2 times higher than the healthcare cost for females without dysmenorrhea [ 17 ]. PD is highly prevalent among Chinese college girls, with a high burden of symptoms affecting productivity and assimilation into society [ 18 ]. With a prevalence rate of over 40% among Chinese College girls, there’s the need to understand why [ 19 ]. Previous study investigates the association between cola consumption and dysmenorrhea in young girls, suggesting a possible link between sugary carbonated beverages and menstrual pain [ 20 ]. Our study buttresses the many previous studies examining the prevalence and characteristics of PD among female undergraduates in China. The relationship between soft drinks intake and the incidence and pain severity of PD is not well documented [ 19 , 21 – 24 ]. To bridge research gap, we conducted a cross-sectional study to analyze the association between soft drinks intake and the incidence/severity of PD among Chinese female undergraduates. This is the first study to analyze the association between soft drinks consumption and PD incidence and severity among Chinese female undergraduates. We also did a stratification analysis according to the place of residence (urban or rural). Methods Study design and sample size considerations We performed a cross-sectional study to analyze the association between soft drinks intake and the incidence and severity of PD among female undergraduates in China from September 29, 2020 to October 22, 2020. The inclusion criteria of the study are: (1) Students from all across China enrolled in Binzhou Medical University in 2019; (2) Female; (3) No history of gyanecologic pathological changes. The distribution of participants is shown in Fig. 1 . All participants had to provide informed consent before participation. This study was approved by Binzhou Medical University ethics committee. We estimated the sample size by n= \(\frac{{Z}_{1-\alpha /2}^{2}\times pq}{{d}^{2}}\) According to Iacovides' study [ 9 ], we conservatively determined that the prevalence ( p ) is 0.45, and we set permissible error ( d ) at 0.1 p , α = 0.05, then the minimum sample size was calculated to be 489. Finally, we included 1809 samples from the Chinese Undergraduates Cohort (CUC). Data collection The participants’ information was collected by a self-administrated questionnaire. This self-administrated questionnaire included demographic information and menstrual information of the participants. Covariates Demographic information include age, residence, smoking, passive smoking, physical activity, carbonated soft drinks intake, carbonated soft drinks intake frequency, coffee intake, and coffee intake frequency. Participants were classified into urban and rural areas. In addition, anthropometric data including height and weight were self-reported. Each participant's Body Mass Index (BMI) was calculated as weight in kilograms divided by the height in meters squared. [ 25 ]. The following demographic information variables were defined as categorical variables and the definitions used were: smoking - at least one cigarette per day in the past three months; passive smoking - at least 15 minutes of passive smoking per day for the past three months; physical activity - at least once a week for the past three months [ 26 ]. Data about soft drinks or coffee intake were collected by the question, “Do you often drink carbonated soft drinks/coffee?”. People who drank soft drinks or coffee had to report the intake frequency, and the frequency was classified as “<1 times/week”, “1–3 times/week”, “4–6 times/week”, “≥7 times/week”. Menstrual information included menstrual cycle, menstrual duration and menstrual flow. Collecting menstrual information was based on those questions: “How often have you menstruated in the past three months?”, “What’s the duration of your menstruation in the past three months?”, “How is the menstrual flow in the past three months?”. PD was identified on the basis of the questions, “Have you experienced one or more of menstrual cramps or abdominal pain during your menstrual period in the past three months?”. Participants with PD had to report the level of their pain severity. The pain severity was categorized as mild, moderate, and severe, which are respectively defined as 1–3 points. Statistical analysis We divided participants into PD group and normal group according to their PD condition. The logistic regression model was used to evaluate the association between soft drinks intake and the incidence as well as severity of PD. The incidence of PD and severity of PD were selected as the dependent variable. The X 2 test was used to compare the between-group differences with and without PD and the distribution difference of PD characteristics between the groups with varying pain severity. Univariate and multivariate binary logistic regression were used to explore the association between study variables and the incidence and severity of PD. Univariate analysis for the presence of PD was carried out with all variables pertaining to demographic and menstrual characteristics. Kruskal-Wallis test was used to determine the association between carbonated soft drinks intake frequency and the severity of PD. Forward LR method was performed to select independent variables obtained from the bivariate analyses. For categorical variables, Chi-square test with a pre-set significance value of ≤ 0.05 was used to test for significant association between soft drinks intake and PD. For the bivariate analysis, the Pearson's chi-squared test was used, together with the Student 's t-test, and the study was concluded using forward selection for binary logistic regression. We also conducted a stratification analysis according to participants’ places of residence (urban or rural) to investigate the association between soft drinks intake and the incidence of PD among different populations in multiple logistic regression. The data extracted from the questionnaires were statistically analyzed using the Statistical Package for Social Sciences (SPSS) 23.0 software after coding all answers. The level of statistically significance was set at p < 0.05. Results Characteristics of the Study Subjects Table 1 shows the baseline demographic characteristics of participants. A total of 1809 participants were recruited in this study. The average age of participants was 19.7 ± 1.2 years. There were 852 (47.1%) participants experienced PD in the past three months. For PD group, 51.2% had consumed carbonated soft drinks compared with 48.8% in non-PD group. Moreover, 44.8% participants of the PD group drank coffee, whereas 55.2% in the non-PD group. There were 906 (50.1%) participants from rural areas. The distribution of the severity of PD cases was as follows: mild 24.4% (n = 208), moderate 49.6% (n = 423), and severe 26.0% (n = 221). Table 1 The distribution of demographic characteristics of participants Primary Dysmenorrhea p -value NO (n = 957) YES (n = 852) Sociodemographic information Location (%) 0.287 Rural 468 (51.7) 438(48.3) Urban 489 (54.2) 414 (45.8) BMI (%) 0.236 Underweight 363 (52.0) 335 (48.0) Normal 462 (52.0) 426 (48.0) Overweight 64 (57.7) 47 (42.3) Obese 68 (60.7) 44(39.3) Lifestyle habits information Smoking (%) 0.604 NO 956 (52.9) 850(47.1) YES 1(33.3) 2(66.7) Passive smoking (%) 0.600 NO 918 (53.0) 813 (47.0) YES 439(50.0) 39(50.0) Physical activity (%) 0.028 NO 224(48.5) 238 (51.5) YES 733 (54.4) 614(45.6) Carbonated soft drinks intake (%) 0.033 NO 720 (54.4) 603 (45.6) YES 237 (48.8) 249(51.2) Tea intake (%) 0.124 NO 808 (52.2) 741 (47.8) YES 149(57.3) 111(42.7) Coffee intake (%) 0.568 NO 877 (52.7) 787 (47.3) YES 80(55.2) 65 (44.8) Carbonated soft drinks intake frequency (%) 0.154 = 7 times/week 5 (50.0) 5 (50.0) Coffee intake frequency (%) 0.591 = 7 times/week 10 (55.6) 8 (44.4) Table 2 reflects the baseline menstrual characteristics of participants in both non-PD and PD groups. Both non-PD and PD groups had a similarity in menstrual cycle. It can be noticed in the menstrual flow data of the participants that those in the PD group reported 62.3% having heavy flow as opposed to the 37.7% reported by the non-PD group. Table 2 The distribution of menstrual characteristics of participants menstrual characteristics Primary Dysmenorrhea p -value NO (n = 957) YES (n = 852) Menstrual cycle (%) 0.101 30 days 252 (49.2) 260 (50.8) Menstrual duration (%) 0.333 5 days 374 (51.5) 352 (48.5) Menstrual flow (%) < 0.001 Mild 63 (52.1) 58 (47.9) Moderate 836 (54.5) 698(45.5) Heavy 58(37.7) 96 (62.3) Carbonated soft drinks intake and PD Table 3 a shows the association between carbonated soft drinks intake and the incidence of PD. The results showed that the risk of PD incidence in carbonated soft drink group was about 1.24 times higher (OR = 1.244, 95%CI = 1.010–1.533) than non-carbonated soft drink group. Table 3 b shows the association between carbonated soft drinks intake frequency and the severity of PD (x̅±s). The results found that there is a dose-response relationship between frequencies of carbonated soft drinks intake and the pain severity of PD. Table 3 a Associations between carbonated soft drink intake and incidence of PD variable OR (95%CI) P -value Carbonated soft drinks NO Ref YES 1.244 (1.010–1.533) 0.040 Table 3 b Associations between carbonated soft drinks intake frequency and the severity of PD (x̅±s) variable N 2 P Carbonated soft drinks intake frequency 9.217 0.027 = 7 times/week 5 Coffee intake and PD Table 4 shows the association between the amount of coffee intake and the severity of PD. After analyzing the variables related to PD severity, we found that there is a significant association between coffee intake and PD severity. Specifically, participants with moderate to severe PD who consume coffee have lower odds of experiencing severe symptoms, with an odds ratio of 0.451 (95% CI = 0.228–0.892) (p < 0.05). Table 4 Associations between coffee intake and the severity of PD (n = 644) variable OR (95%CI) P -value Coffee intake NO Ref YES 0.451(0.228–0.892) 0.019 Table 5 shows the association between coffee intake frequency and the severity of PD (x̅±s) using Kruskal-Wallis test. The results did not find significant associations between coffee drinking frequencies and severity of PD. Table 5 Associations between coffee intake frequency and the severity of PD (x̅±s) variable N 2 P Coffee intake frequency 1.333 0.721 = 7 times/week 8 The associations between menstrual flow and the incidence and severity of PD are shown in Tables S4–S6. Physical activity, menstrual flow and menstrual cycle were associated with the incidence of PD (p < 0.05). DISCUSSION This is the first study to analyze the association between soft drinks consumption and PD incidence and severity among Chinese female undergraduates. Our findings revealed a high prevalence of PD, with 47.1% of participants experiencing it, and 26% of those experiencing severe pain. We found that women who consumed carbonated soft drinks had a higher risk of developing PD. However, those who drink more coffee had less chance of developing into sever PD pain. Prevalence of PD among female undergraduates in China According to our study, there were 46.1% of PD cases among female undergraduates in China, which is comparable to previous studies that reported rates ranging from 40–90% [ 27 ]. A previous study conducted in China indicated that the rate of PD among female university students was 41.7% [ 19 ]. Our study used a self-administered questionnaire to assess the level of pain severity in the subjects, which showed that 24.4% of participants experienced mild pain, 49.6% had moderate pain, and 26.0% had severe pain. A study conducted in Saudi Arabia confirmed our findings, reporting that 23% of participants experienced mild dysmenorrhea, 50% suffered from moderate pain, and 27% reported severe pain [ 28 ]. Although there were slight differences in the percentage distribution of pain severity in different studies, most of the results agree that approximately one-fourth of female undergraduates described their PD as severe [ 22 ]. Similarly, studies conducted in Turkey and other countries have reported the prevalence of severe dysmenorrhea to be between 10% and 27% [ 29 ], indicating that PD is still a significant gynecological and public health issue among female undergraduates. These findings underscore the urgent need for better prevention protocols and intervention measures to address this condition. Relationship between carbonated soft drinks consumption and PD Our study further revealed that the intake of carbonated soft drinks had a statistically significant association with the incidence of PD. We also identified a significant relationship between carbonated soft drinks intake frequency and the severity of PD (p < 0.05). Our findings were backed up by several studies conducted in Turkish [ 29 ], in Ethiopia [ 23 ], Spanish and Ozturk [ 30 ]. These study found a positive correlation between carbonated soft drinks intake and PD incidence [ 25 ]. This could be due to the fact that the high sugar content in carbonated soft drinks can disrupt the absorption and processing of certain vitamins and minerals, leading to nutritional imbalances that can cause abnormal muscle contractions and ultimately muscle spasms [ 29 ]. Besides, the cause of PD is likely related to the cyclooxygenase pathway producing higher levels of prostanoids, specifically prostaglandins (PGs), in the endometrium during ovulation cycles [ 12 , 13 ]. Some studies indicate that the concentration of prostaglandin F2α in menstrual fluid is twice as high in women who experience dysmenorrhea compared to those who don't [ 16 , 31 ]. The elevated levels of PGs bring about contractions in the uterus, resulting in the production of anaerobic metabolites that activate pain receptors [ 12 ]. These metabolites may be derive from meals that contain sugar [ 32 ]. The heightened levels of PGs prompt the uterus to contract, which restricts blood flow and generates anaerobic metabolites that activate pain receptors. Prior study has suggested that consuming excessive sugar can impact the amount of steroids circulating in the body [ 33 ]. High-sugar beverages lead to increased cortisol (steroid) levels in young women. Cortisol is a hormone that is released in response to stress and is involved in regulating various physiological processes in the body. A study found that women with PD had higher levels of cortisol compared to women without menstrual pain, suggesting that the dysregulation of the stress response system, which includes cortisol secretion, may be involved in the development of primary dysmenorrhea [ 34 ]. However, these findings are inconsistent with the results of several other researchers who reported there was no correlation between carbonated soft drinks consumption and PD [ 35 , 36 ] The possible explanation may be there should be a threshold amount of carbonated drinks consumed to be able to cause PD. Normal consumption (not excessive) shows no evidence of a direct relationship with PD. Our study found a significant association between carbonated soft drinks intake frequency and the severity of PD (p < 0.05), which could better account for causal associations than ordinary cross-sectional study. However, additional studies are required to explore the connection between drinking carbonated soft drinks and PD. The relationship between coffee consumption and PD According to our study, drinking coffee has been shown to potentially decrease the risk of developing PD (p > 0.05). However, this finding contradicts some previous studies that have suggested otherwise [ 24 , 37 ]. Specifically, our research indicates that among individuals experiencing moderate to severe pain severity from PD, those who consumed coffee had a 0.451 lower risk compared to those who did not consume coffee. However, no significant correlation was found for participants experiencing only mild pain severity from PD. Our study aligns with a Spanish study that reported a statistically significant association between dysmenorrhea or its severity and factors such as caffeine intake, supporting our results [ 25 ]. Additionally, a study conducted in Saudi Arabia found a significant association between PD and caffeine consumption [ 28 ]. The relationship between coffee intake and PD has been the subject of controversy in previous studies. While some studies have reported a positive association between coffee intake and the risk of PD [ 22 , 38 ], others have found no correlation between PD and daily coffee consumption [ 36 , 39 ]. For instance, a study on medical sciences students at Babol University of Medical Sciences demonstrated that the risk of dysmenorrhea was twice as high in individuals who were high consumers of caffeine (≥ 300mg/day) compared to those who were low/moderate consumers of caffeine (< 300mg/day) (OR = 1.97, 95% CI 1.09 to 3.59) [ 38 ]. The conflicting results of these studies contribute to the controversy surrounding the association between coffee intake and PD. The variations in study designs, sample sizes, and populations may be factors influencing the divergent findings. A study conducted in medical students at Babol University of Medical Sciences found that moderate/moderate caffeine consumers (< 300 mg/day) showed a two-fold higher risk of dysmenorrhea (OR = 1, 97 (95% CI 1.09 to 3.59)) [ 37 ]. Another cross-sectional study of 1,183 women, based on the Shanghai Birth Cohort Study, found that coffee consumption was positively associated with the severity of dysmenorrhea after considering potential confounding factors [ 37 ]. In contrast, the prospective study of 428 women conducted in Saint Vincent and the Grenadines reported no statistically significant association between PD and caffeinated beverages [ 40 ]. Also, a cross-sectional study conducted in Surakarta on 274 female adolescents aged between 15 and 17 years old found that caffeine intake was not significantly associated with the severity of dysmenorrhea [ 41 ]. Additionally, other studies have shown a correlation between caffeine intake and dysmenorrhea [ 22 , 40 ]. Caffeine, the main component of coffee, is an adenosine analogue that blocks adenosine receptors (potent vasodilators) [ 42 ]. Blocking these receptors causes vasoconstriction, reducing blood flow to the uterus and making menstrual pain even worse [ 43 ]. Caffeine also has a strong vasoconstrictor effect and has been associated with pelvic pain. The mechanisms by which caffeine may induce crampy pain have not yet been identified and require further research [ 28 ]. Potential pharmacodynamic effects have been shown for how inn helps in PD. Prostaglandin E1 (PGE1) increases cAMP, which essentially causes smooth muscle relaxation and vasodilation. PGE1 increases during menstruation along with PGE2 and other prostaglandins [ 44 ]. The effectiveness of individual PGs depends on concentration, potency, genetics, etc. Caffeine in coffee synergistically increases PGE1, causing uterine relaxation. Another study showed that a 1mM concentration of caffeine stimulated cyclic AMP levels to 151% of control levels after 60 minutes. Higher concentrations of caffeine produced even greater stimulation of cyclic AMP levels [ 45 ]. We believe our findings further clarify the fact that coffee consumption is not always positively correlated with the severity of PD. More study on this topic is needed. Though there are various hypotheses on mechanism of action between PGE1 and cAMP. For example, PGE1 does at least not exclusively act by changing cAMP levels, but rather directly influences cell membrane functions [ 46 ]. We believe that our study result throws more light on the fact that coffee intake doesn’t always bear a positive correlation with severity of PD pains and that more research is required on the subject matter. Implications for policy and practice Our study has several public health implications. Our study examined the evidence of adverse effects of soft drinks consumption on Chinese female undergraduates, and found that frequent carbonated soft drinks intake is a risk factor for PD whereas coffee intake is a protective factor for PD. There are known non-modifiable risk factors such as menstrual flow and menstrual cycle, are also identified in our study, which increase the probability of suffering from PD. As modifiable risk factors, carbonated soft drinks intake and coffee intake had a significant association with PD. However, concerning lifestyle and eating habits, and based on our results and previous reports, further studies about soft drinks intake are necessary to provide recommendations on the most advisable diets or lifestyle habits for minimizing the consequences or reducing the risk of PD. Firstly, we should formulate corresponding policies to restrict the sale of soft drinks. In addition to strategies at country level, female undergraduates with PD could try to avoid the frequent intake of soft drinks, especially carbonated soft drinks and find other substitutes such as some type of tea (black tea, matcha green tea, etc..) or coffee. Limitations and future directions The advantages of our study are also worth noting. The large sample size made the results more precise. In addition, this study was based on a large cohort, which enables us to involve more potential confounders in the analyses. This study explored the association between soft drinks intake and the incidence as well as the severity of PD among female undergraduates. We have, in our discussion, highlighted a few issues that require further comprehensive research such as carbonated soft drinks intake (a risk factor) and coffee intake (a protective factor). We also divided the degree of PD pain severity into 3 levels of and further explored the impact of soft drinks intake on PD under the different levels of pain severity of PD. What‘s more, we have also done the stratification analysis which enabled us explore the association between soft drink consumption and PD in different groups according to their places of residence (urban or rural). Our results indicated a significantly positive association between soft drinks intake and PD, which bear notable public health ramifications. We are aware of some limitations. First, the study design is a cross-sectional study with no causal interpretation. Second, although the students in the sample are not only from Shandong, there are relatively many students from Shandong, so the sample may not be representative of all Chinese women. Further generalization of results in the future requires an expansion of the proportions of sample in different areas in China. Finally, pain is a subjective issue, and if people want to rate pain intensity, pain perception is influenced by several factors such as culture, social conditions, and lifestyle, and the self-reported nature of it can lead to memory bias and over-reporting or underreporting of some variables. Despite these limitations, our study can be used to increase general perceptions of PD among Chinese female students. Conclusion Overall, a high portion of female undergraduates suffer from PD in China. We identified that carbonated soft drinks were a risk factor for the occurrence and severity of PD, while coffee consumption was a protective factor against PD. Being aware of this makes it possible for health professionals to organize better focused programs to reduce the adverse effects of PD. Our findings highlight the need for interventions to reduce undergraduates’ soft drinks consumption by educating them about the harmful effects of soft drinks. Declarations Acknowledgements The authors wish to thank all undergraduates who participated in the study for their collaboration in the study. Contributions Lijiao Wang : Methodology, Formal analysis, Software, Writing – original draft, Writing – review & editing. Lingyan Qiao :Software, Formal analysis, Resources, Writing – review & editing. Shuo Wen : Methodology, Formal analysis, Software, Resources, Writing – review & editing. Xinyuan Li : Methodology, Software, Formal analysis, Resources, Writing – review & editing. Ahiafor Maxwell : Resources, Writing – review & editing. Qiang Guo : Supervision, Methodology, Resources, Writing – review & editing, Funding acquisition. Peng Lu : Conceptualization, Supervision, Methodology, Project administration, Resources, Writing – review & editing, Funding acquisition. Funding No Funding. Availability of data and materials Data described in the manuscript, code book, and analytic code will be made available upon request pending application to and approval from the corresponding author PL. Ethics approval and consent to participate This study was conducted according to the guidelines laid down in the Declaration of Helsinki and all procedures involving research study participants were approved by Binzhou Medical University ethics committee (NO.2019075). Written informed consent was obtained from all subjects. Patient consent for publication Not required. Competing interests The authors declare no competing interests. References Vartanian, L. R., Schwartz, M. B., & Brownell, K. D. J. A. J. O. P. H. (2007). 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A cross-sectional study. *Journal of Women’s Health, 41*(3), 283-289. Cakir, M., et al. (2010). Menstrual pattern and common menstrual disorders among university students in Turkey. *Journal of Women’s Health, 49*(6), 938-942. Hizmetleri, Y. Y. W. T., & Com, I. J. Y. W. T. H. -D. (n.d.). Hosting, Design, Dysmenorrhea Prevalence in Women Who Applied to Gynaecology and Obstetrics Policlinics and Affecting Factors. Bhat., A. S. J. I. J. O. M., & Healthence, E. (2013). EFFICACY OF HIJAMAT BILA SHURT (DRY CUPPING) ON PAIN RELIEF IN PRIMARY DYSMENORRHEA. *Journal of Women’s Health, 21*(3). Muluneh, A. A., et al. (2018). Prevalence and associated factors of dysmenorrhea among secondary and preparatory school students in Debremarkos town, North-West Ethiopia. *BMC Women’s Health, 18*(1), 57. Gagua, T., Tkeshelashvili, B., & Gagua, D. J. J. O. T. T. G. G. A. (2012). Primary dysmenorrhea: prevalence in adolescent population of Tbilisi, Georgia and risk factors. *Journal of Women’s Health, 13*(3), 162-8. Stratton, P., & Berkley, K. J. J. H. R. U. (2011). Chronic pelvic pain and endometriosis: translational evidence of the relationship and implications. *Journal of Women’s Health, 3*(3), 17. Mualla, A., et al. (2007). The Impact of Some Biological, Socio-Demographic and Nutritional Factors on the Prevalence of Dysmenorrhea. *Journal of Women’s Health, 2007*. Unsal, A., et al. (2010). Evaluation of dysmenorrhea among women and its impact on quality of life in a region of western Turkey. *Journal of Women’s Health, 26*(1). Zhang, X., et al. (2019). Association of tea drinking and dysmenorrhea among reproductive-age women in Shanghai, China (2013–2015): a cross-sectional study. *Journal of Women’s Health, 9*(4), e026643. Faramarzi, M., & Salmalian, H. J. I. R. C. M. J. (2014). Association of Psychologic and Nonpsychologic Factors With Primary Dysmenorrhea. *Journal of Women’s Health, 16*(8). Alia, S. M., Shamssain, M., & Shahwan, M. (n.d.). Prevalence and Impact of Dysmenorrhea on Health-Related Quality of Life in the United Arab Emirates. Monday, I., et al. (2019). Prevalence and Correlation between Diet and Dysmenorrhea among High School and College Students in Saint Vincent and Grenadines. *Journal of Women’s Health, 7*(6), 920-924. Wrisnijati, D., Wiboworini, B., & Sugiarto, S. J. J. G. d. P. S. (2019). Prevalence and Factor Associated with Severity of Dysmenorrhea Among Female Adolescent in Surakarta. *Journal of Women’s Health, 3*(1), 76. Ribeiro, J. A., & Jad, A. M. S. J. J. O. A. D. (2010). Caffeine and Adenosine. *Journal of Women’s Health, 20 Suppl 1(Suppl. 1), S3. Scandinavica, M. Å. J. A. O. e. G. (1979). Pathophysiology of Dysmenorrhea. *Journal of Women’s Health, 1979*. Ninagawa, T., et al. (1981). Prostaglandins and dysmenorrhea effect of naproxen on prostaglandin concentrations in menstrual blood (author’s transl)]. *Journal of Women’s Health, 33*(4), 449. Claire, et al. (1986). Caffeine effects on cyclic AMP levels in the mouse embryonic limb and palate in vitro. *Journal of Women’s Health, 34*(1), 21-27. Oropeza-Rendon, R. L., & Bauer, I. C. (n.d.). Effect of prostaglandin E on the level of camp in bone shape changes marrow macrophages. Inhibition of phagocytosis and cell +. *Journal of Women’s Health*. Additional Declarations No competing interests reported. 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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-4389961","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":306099638,"identity":"22d6f4b9-2b5a-43b0-bb76-2c0db142e4b3","order_by":0,"name":"Lijiao Wang","email":"","orcid":"","institution":"Binzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Lijiao","middleName":"","lastName":"Wang","suffix":""},{"id":306099639,"identity":"ba40c897-1e69-41e9-9ff3-917259e5e728","order_by":1,"name":"Lingyan Qiao","email":"","orcid":"","institution":"Binzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Lingyan","middleName":"","lastName":"Qiao","suffix":""},{"id":306099640,"identity":"66f47a4d-48d2-4149-bbda-9ef956ef0a46","order_by":2,"name":"Shuo Wen","email":"","orcid":"","institution":"Binzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Shuo","middleName":"","lastName":"Wen","suffix":""},{"id":306099641,"identity":"8a188801-28e5-421c-9608-59829316558b","order_by":3,"name":"Xinyuan Li","email":"","orcid":"","institution":"Binzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xinyuan","middleName":"","lastName":"Li","suffix":""},{"id":306099642,"identity":"6e35c274-7829-441c-ac20-72eef627befd","order_by":4,"name":"Ahiafor Maxwell","email":"","orcid":"","institution":"Binzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ahiafor","middleName":"","lastName":"Maxwell","suffix":""},{"id":306099643,"identity":"7c15b063-2ed8-48e7-adf9-ef831a48edb2","order_by":5,"name":"Qiang Guo","email":"","orcid":"","institution":"Zhejiang Normal University","correspondingAuthor":false,"prefix":"","firstName":"Qiang","middleName":"","lastName":"Guo","suffix":""},{"id":306099644,"identity":"9cdae3b8-b790-4a7e-bd2e-4af56ccc5a31","order_by":6,"name":"Peng Lu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYNCCAgY5MM3YACQOEKXFgMGYdC2JDURrMWfvPfyCweBw+tr23oMff+5gkOO7kYBfi2XPuTQLoJbcbWfOJUvznmEwliSkxeBGjpkBWMuNHANpxjaGxA0Etdx/A9aSbnYjx/jnzzaGesJabvAYPwBqSQBqMZPgbWNIMCDslxwzoLJ0w21nzphZ87ZJGM488wC/FnP2M8YfPlRYy5sd7zG++bPNRp7vOCGHMTCwSSCpkcCvHKqF+QNhZaNgFIyCUTCiAQCSPEb4lDRctgAAAABJRU5ErkJggg==","orcid":"","institution":"Binzhou Medical University","correspondingAuthor":true,"prefix":"","firstName":"Peng","middleName":"","lastName":"Lu","suffix":""}],"badges":[],"createdAt":"2024-05-08 14:27:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4389961/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4389961/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-71802-8","type":"published","date":"2024-09-11T15:57:25+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":57442809,"identity":"fb2f5b4c-1151-4547-8a2f-15a00d124959","added_by":"auto","created_at":"2024-05-30 18:48:31","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":102479,"visible":true,"origin":"","legend":"\u003cp\u003eThe distribution of the participants\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4389961/v1/cb5f26eb11834c0030b6bea1.png"},{"id":64619074,"identity":"d4f7e25d-db18-45be-b16e-03b7824d45bf","added_by":"auto","created_at":"2024-09-16 16:11:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":878660,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4389961/v1/6cfb5327-4331-48d6-94e3-fb89f0077a9a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Associations between Soft drinks intake and Primary Dysmenorrhea: A Cross-sectional Study among Chinese undergraduate female students","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eSoft drinks include soda water, syrup, or other carbonated or non-carbonated beverages [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Also known sometimes as carbonated beverages or sodas, soft drinks are non-alcoholic beverages that are typically carbonated and flavored. Coffee is considered a beverage that is brewed from roasted coffee beans [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. One of the primary ingredients in soft drinks is sugar, with an average content 100 g/L [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The global consumption of soft drinks has increased dramatically over the past several decades with the greatest increase among young people [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. While the exact amount differs from study to study, they all indicate that soft drink consumption has been on the rise in China in recent years [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], resulting in a remarkably increase in various health conditions and diseases.\u003c/p\u003e \u003cp\u003eSimilarly, coffee consumption which was considered a western lifestyle, has significantly gained popularity in China, a country with long history of drinking green tea. The demand for coffee has also grown rapidly in recent years [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Statistical reports show that Chinese population consumed around 4.8\u0026nbsp;million 60-kilogram bags of coffee, as coffee production volume in China amounted to around 1.8\u0026nbsp;million bags in the same period. Although considered a beverage, coffee has a stimulant effect on the human nervous system due to it\u0026rsquo;s caffeine content [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Notable of these effects are ; caffeine in coffee possess an antagonistic effect on adenosine A1 and A2A receptors, causing hyperexcitability of the central nervous system [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], also affects physical stamina, cognitive function and in some cases amplify symptoms of anxiety [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrimary dysmenorrhea(PD)is defined as painful menstruation in absence of pelvic pathological changes, characterized by recurrent, cramp-like lower abdominal pain during menstruation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. It doubles as the most common gynecologic condition and one of the most common causes of pelvic pain in pre-menopausal women [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The prevalence of PD among female university students varies widely, ranging from 45\u0026ndash;95% [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Though not a life-threatening condition, PD can cause substantial burden on the quality of life [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In the United States, about 600\u0026nbsp;million work hours and 2\u0026nbsp;billion dollars annual economic loss has been attributed to PD [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In Japan, it has been reported that the total healthcare cost for patients with PD is 2.2 times higher than the healthcare cost for females without dysmenorrhea [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. PD is highly prevalent among Chinese college girls, with a high burden of symptoms affecting productivity and assimilation into society [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. With a prevalence rate of over 40% among Chinese College girls, there\u0026rsquo;s the need to understand why [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrevious study investigates the association between cola consumption and dysmenorrhea in young girls, suggesting a possible link between sugary carbonated beverages and menstrual pain [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Our study buttresses the many previous studies examining the prevalence and characteristics of PD among female undergraduates in China. The relationship between soft drinks intake and the incidence and pain severity of PD is not well documented [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan additionalcitationids=\"CR22 CR23\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo bridge research gap, we conducted a cross-sectional study to analyze the association between soft drinks intake and the incidence/severity of PD among Chinese female undergraduates. This is the first study to analyze the association between soft drinks consumption and PD incidence and severity among Chinese female undergraduates. We also did a stratification analysis according to the place of residence (urban or rural).\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and sample size considerations\u003c/h2\u003e \u003cp\u003eWe performed a cross-sectional study to analyze the association between soft drinks intake and the incidence and severity of PD among female undergraduates in China from September 29, 2020 to October 22, 2020. The inclusion criteria of the study are: (1) Students from all across China enrolled in Binzhou Medical University in 2019; (2) Female; (3) No history of gyanecologic pathological changes. The distribution of participants is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. All participants had to provide informed consent before participation. This study was approved by Binzhou Medical University ethics committee. We estimated the sample size by\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003en=\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\frac{{Z}_{1-\\alpha /2}^{2}\\times pq}{{d}^{2}}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003eAccording to Iacovides' study [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], we conservatively determined that the prevalence (\u003cem\u003ep\u003c/em\u003e) is 0.45, and we set permissible error (\u003cem\u003ed\u003c/em\u003e) at 0.1\u003cem\u003ep\u003c/em\u003e, α\u0026thinsp;=\u0026thinsp;0.05, then the minimum sample size was calculated to be 489. Finally, we included 1809 samples from the Chinese Undergraduates Cohort (CUC).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eData collection\u003c/h2\u003e \u003cp\u003eThe participants\u0026rsquo; information was collected by a self-administrated questionnaire. This self-administrated questionnaire included demographic information and menstrual information of the participants.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eCovariates\u003c/h2\u003e \u003cp\u003eDemographic information include age, residence, smoking, passive smoking, physical activity, carbonated soft drinks intake, carbonated soft drinks intake frequency, coffee intake, and coffee intake frequency. Participants were classified into urban and rural areas. In addition, anthropometric data including height and weight were self-reported. Each participant's Body Mass Index (BMI) was calculated as weight in kilograms divided by the height in meters squared. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The following demographic information variables were defined as categorical variables and the definitions used were: smoking - at least one cigarette per day in the past three months; passive smoking - at least 15 minutes of passive smoking per day for the past three months; physical activity - at least once a week for the past three months [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Data about soft drinks or coffee intake were collected by the question, \u0026ldquo;Do you often drink carbonated soft drinks/coffee?\u0026rdquo;. People who drank soft drinks or coffee had to report the intake frequency, and the frequency was classified as \u0026ldquo;\u0026lt;1 times/week\u0026rdquo;, \u0026ldquo;1\u0026ndash;3 times/week\u0026rdquo;, \u0026ldquo;4\u0026ndash;6 times/week\u0026rdquo;, \u0026ldquo;\u0026ge;7 times/week\u0026rdquo;.\u003c/p\u003e \u003cp\u003eMenstrual information included menstrual cycle, menstrual duration and menstrual flow. Collecting menstrual information was based on those questions: \u0026ldquo;How often have you menstruated in the past three months?\u0026rdquo;, \u0026ldquo;What\u0026rsquo;s the duration of your menstruation in the past three months?\u0026rdquo;, \u0026ldquo;How is the menstrual flow in the past three months?\u0026rdquo;. PD was identified on the basis of the questions, \u0026ldquo;Have you experienced one or more of menstrual cramps or abdominal pain during your menstrual period in the past three months?\u0026rdquo;. Participants with PD had to report the level of their pain severity. The pain severity was categorized as mild, moderate, and severe, which are respectively defined as 1\u0026ndash;3 points.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eWe divided participants into PD group and normal group according to their PD condition. The logistic regression model was used to evaluate the association between soft drinks intake and the incidence as well as severity of PD. The incidence of PD and severity of PD were selected as the dependent variable. The X\u003csup\u003e2\u003c/sup\u003e test was used to compare the between-group differences with and without PD and the distribution difference of PD characteristics between the groups with varying pain severity. Univariate and multivariate binary logistic regression were used to explore the association between study variables and the incidence and severity of PD. Univariate analysis for the presence of PD was carried out with all variables pertaining to demographic and menstrual characteristics. Kruskal-Wallis test was used to determine the association between carbonated soft drinks intake frequency and the severity of PD. Forward LR method was performed to select independent variables obtained from the bivariate analyses. For categorical variables, Chi-square test with a pre-set significance value of \u0026le;\u0026thinsp;0.05 was used to test for significant association between soft drinks intake and PD. For the bivariate analysis, the Pearson's chi-squared test was used, together with the Student 's t-test, and the study was concluded using forward selection for binary logistic regression.\u003c/p\u003e \u003cp\u003eWe also conducted a stratification analysis according to participants\u0026rsquo; places of residence (urban or rural) to investigate the association between soft drinks intake and the incidence of PD among different populations in multiple logistic regression. The data extracted from the questionnaires were statistically analyzed using the Statistical Package for Social Sciences (SPSS) 23.0 software after coding all answers. The level of statistically significance was set at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eCharacteristics of the Study Subjects\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the baseline demographic characteristics of participants. A total of 1809 participants were recruited in this study. The average age of participants was 19.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 years. There were 852 (47.1%) participants experienced PD in the past three months. For PD group, 51.2% had consumed carbonated soft drinks compared with 48.8% in non-PD group. Moreover, 44.8% participants of the PD group drank coffee, whereas 55.2% in the non-PD group. There were 906 (50.1%) participants from rural areas. The distribution of the severity of PD cases was as follows: mild 24.4% (n\u0026thinsp;=\u0026thinsp;208), moderate 49.6% (n\u0026thinsp;=\u0026thinsp;423), and severe 26.0% (n\u0026thinsp;=\u0026thinsp;221).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe distribution of demographic characteristics of participants\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\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003ePrimary Dysmenorrhea\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNO (n\u0026thinsp;=\u0026thinsp;957)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYES (n\u0026thinsp;=\u0026thinsp;852)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSociodemographic information\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eLocation (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.287\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eRural\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e468 (51.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e438(48.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eUrban\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e489 (54.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e414 (45.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eBMI (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.236\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eUnderweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e363 (52.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e335 (48.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNormal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e462 (52.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e426 (48.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eOverweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64 (57.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47 (42.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eObese\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68 (60.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e44(39.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLifestyle habits information\u003c/b\u003e\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 \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSmoking (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.604\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e956 (52.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e850(47.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eYES\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2(66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePassive smoking (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.600\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e918 (53.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e813 (47.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eYES\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e439(50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39(50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePhysical activity (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.028\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e224(48.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e238 (51.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eYES\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e733 (54.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e614(45.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eCarbonated soft drinks intake (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.033\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e720 (54.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e603 (45.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eYES\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e237 (48.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e249(51.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eTea intake (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.124\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e808 (52.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e741 (47.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eYES\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e149(57.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e111(42.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eCoffee intake (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.568\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e877 (52.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e787 (47.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eYES\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80(55.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65 (44.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eCarbonated soft drinks intake frequency (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.154\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e720 (54.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e603 (45.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e1\u0026ndash;3 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e210(48.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e226(51.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e4\u0026ndash;6 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (55.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u0026gt;= 7 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eCoffee intake frequency (%)\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 \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.591\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e877 (52.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e787 (47.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e1\u0026ndash;3 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e574 (52.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e49 (47.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e4\u0026ndash;6 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16(66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u0026gt;= 7 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (55.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (44.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e reflects the baseline menstrual characteristics of participants in both non-PD and PD groups. Both non-PD and PD groups had a similarity in menstrual cycle. It can be noticed in the menstrual flow data of the participants that those in the PD group reported 62.3% having heavy flow as opposed to the 37.7% reported by the non-PD group.\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\u003eThe distribution of menstrual characteristics of participants\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" 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\u003emenstrual characteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003ePrimary Dysmenorrhea\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNO (n\u0026thinsp;=\u0026thinsp;957)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eYES (n\u0026thinsp;=\u0026thinsp;852)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMenstrual cycle (%)\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 \u003cp\u003e0.101\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;28 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e421 (55.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e340 (44.7)\u003c/p\u003e \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\u003e28\u0026ndash;30 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e284 (53.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e252 (47.0)\u003c/p\u003e \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\u003e\u0026gt;\u0026thinsp;30 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e252 (49.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e260 (50.8)\u003c/p\u003e \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\u003eMenstrual duration (%)\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 \u003cp\u003e0.333\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;= 5 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e583 (53.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e500 (46.2)\u003c/p\u003e \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\u003e\u0026gt;\u0026thinsp;5 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e374 (51.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e352 (48.5)\u003c/p\u003e \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\u003eMenstrual flow (%)\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 \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e63 (52.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e58 (47.9)\u003c/p\u003e \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\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e836 (54.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e698(45.5)\u003c/p\u003e \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\u003eHeavy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58(37.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e96 (62.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eCarbonated soft drinks intake and PD\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e3\u003c/span\u003ea shows the association between carbonated soft drinks intake and the incidence of PD. The results showed that the risk of PD incidence in carbonated soft drink group was about 1.24 times higher (OR\u0026thinsp;=\u0026thinsp;1.244, 95%CI\u0026thinsp;=\u0026thinsp;1.010\u0026ndash;1.533) than non-carbonated soft drink group. Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e3\u003c/span\u003eb shows the association between carbonated soft drinks intake frequency and the severity of PD (x̅\u0026plusmn;s). The results found that there is a dose-response relationship between frequencies of carbonated soft drinks intake and the pain severity of PD.\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\u003e\u003cb\u003ea\u003c/b\u003e Associations between carbonated soft drink intake and incidence of PD\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003evariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOR (95%CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCarbonated soft drinks\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRef\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\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=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e1.244 (1.010\u0026ndash;1.533)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.040\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \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 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eb\u003c/b\u003e Associations between carbonated soft drinks intake frequency and the severity of PD (x̅\u0026plusmn;s)\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003evariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCarbonated soft drinks intake frequency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.217\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.027\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e603\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\u003e1\u0026ndash;3 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e226\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\u003e4\u0026ndash;6 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\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\u003e\u0026gt;= 7 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\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 \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eCoffee intake and PD\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the association between the amount of coffee intake and the severity of PD. After analyzing the variables related to PD severity, we found that there is a significant association between coffee intake and PD severity. Specifically, participants with moderate to severe PD who consume coffee have lower odds of experiencing severe symptoms, with an odds ratio of 0.451 (95% CI\u0026thinsp;=\u0026thinsp;0.228\u0026ndash;0.892) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\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 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAssociations between coffee intake and the severity of PD (n\u0026thinsp;=\u0026thinsp;644)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003evariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOR (95%CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoffee intake\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRef\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\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=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.451(0.228\u0026ndash;0.892)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e0.019\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the association between coffee intake frequency and the severity of PD (x̅\u0026plusmn;s) using Kruskal-Wallis test. The results did not find significant associations between coffee drinking frequencies and severity of PD.\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 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAssociations between coffee intake frequency and the severity of PD (x̅\u0026plusmn;s)\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003evariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoffee intake frequency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.333\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.721\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e787\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\u003e1\u0026ndash;3 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e49\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\u003e4\u0026ndash;6 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\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\u003e\u0026gt;= 7 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\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 \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe associations between menstrual flow and the incidence and severity of PD are shown in Tables S4\u0026ndash;S6. Physical activity, menstrual flow and menstrual cycle were associated with the incidence of PD (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis is the first study to analyze the association between soft drinks consumption and PD incidence and severity among Chinese female undergraduates. Our findings revealed a high prevalence of PD, with 47.1% of participants experiencing it, and 26% of those experiencing severe pain. We found that women who consumed carbonated soft drinks had a higher risk of developing PD. However, those who drink more coffee had less chance of developing into sever PD pain.\u003c/p\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003ePrevalence of PD among female undergraduates in China\u003c/h2\u003e \u003cp\u003eAccording to our study, there were 46.1% of PD cases among female undergraduates in China, which is comparable to previous studies that reported rates ranging from 40\u0026ndash;90% [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. A previous study conducted in China indicated that the rate of PD among female university students was 41.7% [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Our study used a self-administered questionnaire to assess the level of pain severity in the subjects, which showed that 24.4% of participants experienced mild pain, 49.6% had moderate pain, and 26.0% had severe pain. A study conducted in Saudi Arabia confirmed our findings, reporting that 23% of participants experienced mild dysmenorrhea, 50% suffered from moderate pain, and 27% reported severe pain [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough there were slight differences in the percentage distribution of pain severity in different studies, most of the results agree that approximately one-fourth of female undergraduates described their PD as severe [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Similarly, studies conducted in Turkey and other countries have reported the prevalence of severe dysmenorrhea to be between 10% and 27% [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], indicating that PD is still a significant gynecological and public health issue among female undergraduates. These findings underscore the urgent need for better prevention protocols and intervention measures to address this condition.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eRelationship between carbonated soft drinks consumption and PD\u003c/h2\u003e \u003cp\u003eOur study further revealed that the intake of carbonated soft drinks had a statistically significant association with the incidence of PD. We also identified a significant relationship between carbonated soft drinks intake frequency and the severity of PD (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Our findings were backed up by several studies conducted in Turkish [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], in Ethiopia [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], Spanish and Ozturk [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. These study found a positive correlation between carbonated soft drinks intake and PD incidence [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. This could be due to the fact that the high sugar content in carbonated soft drinks can disrupt the absorption and processing of certain vitamins and minerals, leading to nutritional imbalances that can cause abnormal muscle contractions and ultimately muscle spasms [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBesides, the cause of PD is likely related to the cyclooxygenase pathway producing higher levels of prostanoids, specifically prostaglandins (PGs), in the endometrium during ovulation cycles [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Some studies indicate that the concentration of prostaglandin F2α in menstrual fluid is twice as high in women who experience dysmenorrhea compared to those who don't [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The elevated levels of PGs bring about contractions in the uterus, resulting in the production of anaerobic metabolites that activate pain receptors [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. These metabolites may be derive from meals that contain sugar [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The heightened levels of PGs prompt the uterus to contract, which restricts blood flow and generates anaerobic metabolites that activate pain receptors. Prior study has suggested that consuming excessive sugar can impact the amount of steroids circulating in the body [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. High-sugar beverages lead to increased cortisol (steroid) levels in young women. Cortisol is a hormone that is released in response to stress and is involved in regulating various physiological processes in the body. A study found that women with PD had higher levels of cortisol compared to women without menstrual pain, suggesting that the dysregulation of the stress response system, which includes cortisol secretion, may be involved in the development of primary dysmenorrhea [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, these findings are inconsistent with the results of several other researchers who reported there was no correlation between carbonated soft drinks consumption and PD [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] The possible explanation may be there should be a threshold amount of carbonated drinks consumed to be able to cause PD. Normal consumption (not excessive) shows no evidence of a direct relationship with PD. Our study found a significant association between carbonated soft drinks intake frequency and the severity of PD (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), which could better account for causal associations than ordinary cross-sectional study. However, additional studies are required to explore the connection between drinking carbonated soft drinks and PD.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eThe relationship between coffee consumption and PD\u003c/h2\u003e \u003cp\u003eAccording to our study, drinking coffee has been shown to potentially decrease the risk of developing PD (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). However, this finding contradicts some previous studies that have suggested otherwise [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Specifically, our research indicates that among individuals experiencing moderate to severe pain severity from PD, those who consumed coffee had a 0.451 lower risk compared to those who did not consume coffee. However, no significant correlation was found for participants experiencing only mild pain severity from PD.\u003c/p\u003e \u003cp\u003eOur study aligns with a Spanish study that reported a statistically significant association between dysmenorrhea or its severity and factors such as caffeine intake, supporting our results [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Additionally, a study conducted in Saudi Arabia found a significant association between PD and caffeine consumption [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe relationship between coffee intake and PD has been the subject of controversy in previous studies. While some studies have reported a positive association between coffee intake and the risk of PD [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], others have found no correlation between PD and daily coffee consumption [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. For instance, a study on medical sciences students at Babol University of Medical Sciences demonstrated that the risk of dysmenorrhea was twice as high in individuals who were high consumers of caffeine (\u0026ge;\u0026thinsp;300mg/day) compared to those who were low/moderate consumers of caffeine (\u0026lt;\u0026thinsp;300mg/day) (OR\u0026thinsp;=\u0026thinsp;1.97, 95% CI 1.09 to 3.59) [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. The conflicting results of these studies contribute to the controversy surrounding the association between coffee intake and PD. The variations in study designs, sample sizes, and populations may be factors influencing the divergent findings. A study conducted in medical students at Babol University of Medical Sciences found that moderate/moderate caffeine consumers (\u0026lt;\u0026thinsp;300 mg/day) showed a two-fold higher risk of dysmenorrhea (OR\u0026thinsp;=\u0026thinsp;1, 97 (95% CI 1.09 to 3.59)) [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Another cross-sectional study of 1,183 women, based on the Shanghai Birth Cohort Study, found that coffee consumption was positively associated with the severity of dysmenorrhea after considering potential confounding factors [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn contrast, the prospective study of 428 women conducted in Saint Vincent and the Grenadines reported no statistically significant association between PD and caffeinated beverages [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Also, a cross-sectional study conducted in Surakarta on 274 female adolescents aged between 15 and 17 years old found that caffeine intake was not significantly associated with the severity of dysmenorrhea [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. Additionally, other studies have shown a correlation between caffeine intake and dysmenorrhea [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Caffeine, the main component of coffee, is an adenosine analogue that blocks adenosine receptors (potent vasodilators) [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. Blocking these receptors causes vasoconstriction, reducing blood flow to the uterus and making menstrual pain even worse [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Caffeine also has a strong vasoconstrictor effect and has been associated with pelvic pain. The mechanisms by which caffeine may induce crampy pain have not yet been identified and require further research [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePotential pharmacodynamic effects have been shown for how inn helps in PD. Prostaglandin E1 (PGE1) increases cAMP, which essentially causes smooth muscle relaxation and vasodilation. PGE1 increases during menstruation along with PGE2 and other prostaglandins [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. The effectiveness of individual PGs depends on concentration, potency, genetics, etc. Caffeine in coffee synergistically increases PGE1, causing uterine relaxation. Another study showed that a 1mM concentration of caffeine stimulated cyclic AMP levels to 151% of control levels after 60 minutes. Higher concentrations of caffeine produced even greater stimulation of cyclic AMP levels [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. We believe our findings further clarify the fact that coffee consumption is not always positively correlated with the severity of PD. More study on this topic is needed. Though there are various hypotheses on mechanism of action between PGE1 and cAMP. For example, PGE1 does at least not exclusively act by changing cAMP levels, but rather directly influences cell membrane functions [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]. We believe that our study result throws more light on the fact that coffee intake doesn\u0026rsquo;t always bear a positive correlation with severity of PD pains and that more research is required on the subject matter.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eImplications for policy and practice\u003c/h2\u003e \u003cp\u003eOur study has several public health implications. Our study examined the evidence of adverse effects of soft drinks consumption on Chinese female undergraduates, and found that frequent carbonated soft drinks intake is a risk factor for PD whereas coffee intake is a protective factor for PD. There are known non-modifiable risk factors such as menstrual flow and menstrual cycle, are also identified in our study, which increase the probability of suffering from PD. As modifiable risk factors, carbonated soft drinks intake and coffee intake had a significant association with PD. However, concerning lifestyle and eating habits, and based on our results and previous reports, further studies about soft drinks intake are necessary to provide recommendations on the most advisable diets or lifestyle habits for minimizing the consequences or reducing the risk of PD. Firstly, we should formulate corresponding policies to restrict the sale of soft drinks. In addition to strategies at country level, female undergraduates with PD could try to avoid the frequent intake of soft drinks, especially carbonated soft drinks and find other substitutes such as some type of tea (black tea, matcha green tea, etc..) or coffee.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eLimitations and future directions\u003c/h2\u003e \u003cp\u003eThe advantages of our study are also worth noting. The large sample size made the results more precise. In addition, this study was based on a large cohort, which enables us to involve more potential confounders in the analyses. This study explored the association between soft drinks intake and the incidence as well as the severity of PD among female undergraduates. We have, in our discussion, highlighted a few issues that require further comprehensive research such as carbonated soft drinks intake (a risk factor) and coffee intake (a protective factor). We also divided the degree of PD pain severity into 3 levels of and further explored the impact of soft drinks intake on PD under the different levels of pain severity of PD. What\u0026lsquo;s more, we have also done the stratification analysis which enabled us explore the association between soft drink consumption and PD in different groups according to their places of residence (urban or rural). Our results indicated a significantly positive association between soft drinks intake and PD, which bear notable public health ramifications.\u003c/p\u003e \u003cp\u003eWe are aware of some limitations. First, the study design is a cross-sectional study with no causal interpretation. Second, although the students in the sample are not only from Shandong, there are relatively many students from Shandong, so the sample may not be representative of all Chinese women. Further generalization of results in the future requires an expansion of the proportions of sample in different areas in China. Finally, pain is a subjective issue, and if people want to rate pain intensity, pain perception is influenced by several factors such as culture, social conditions, and lifestyle, and the self-reported nature of it can lead to memory bias and over-reporting or underreporting of some variables. Despite these limitations, our study can be used to increase general perceptions of PD among Chinese female students.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOverall, a high portion of female undergraduates suffer from PD in China. We identified that carbonated soft drinks were a risk factor for the occurrence and severity of PD, while coffee consumption was a protective factor against PD. Being aware of this makes it possible for health professionals to organize better focused programs to reduce the adverse effects of PD. Our findings highlight the need for interventions to reduce undergraduates\u0026rsquo; soft drinks consumption by educating them about the harmful effects of soft drinks.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors wish to thank all undergraduates who participated in the study for their collaboration in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eContributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLijiao Wang\u003c/strong\u003e: Methodology, Formal analysis, Software, Writing \u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing. \u003cstrong\u003eLingyan Qiao\u003c/strong\u003e:Software, Formal analysis, Resources, Writing \u0026ndash; review \u0026amp; editing.\u003cstrong\u003eShuo Wen\u003c/strong\u003e: Methodology, Formal analysis, Software, Resources, Writing \u0026ndash; review \u0026amp; editing. \u003cstrong\u003eXinyuan Li\u003c/strong\u003e: Methodology, Software, Formal analysis, Resources, Writing \u0026ndash; review \u0026amp; editing. \u003cstrong\u003eAhiafor Maxwell\u003c/strong\u003e: Resources, Writing \u0026ndash; review \u0026amp; editing. \u003cstrong\u003eQiang Guo\u003c/strong\u003e: Supervision, Methodology, Resources, Writing \u0026ndash; review \u0026amp; editing, Funding acquisition. \u003cstrong\u003ePeng Lu\u003c/strong\u003e: Conceptualization, Supervision, Methodology, Project administration, Resources, Writing \u0026ndash; review \u0026amp; editing, Funding acquisition.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo Funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData described in the manuscript, code book, and analytic code will be made available upon request pending application to and approval from the corresponding author PL.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted according to the guidelines laid down in the Declaration of Helsinki and all procedures involving research study participants were approved by Binzhou Medical University ethics committee (NO.2019075). Written informed consent was obtained from all subjects.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePatient consent for publication\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNot required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eVartanian, L. R., Schwartz, M. B., \u0026amp; Brownell, K. D. J. A. J. O. P. H. (2007). Effects of Soft Drink Consumption on Nutrition and Health: A Systematic Review and Meta-Analysis. *American Journal of Clinical Nutrition, 85*(4), 667-675.\u003c/li\u003e\n\u003cli\u003eMalik, V. S., et al. (2010). Sugar-Sweetened Beverages and Risk of Metabolic Syndrome and Type 2 Diabetes: A meta-analysis. *Journal of Diabetes Research, 2010*(11).\u003c/li\u003e\n\u003cli\u003eLien, L., et al. (2006). 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Prevalence of Primary Dysmenorrhea and Factors Associated with Its Intensity Among Undergraduate Students: A Cross-sectional Study. *Journal of Women\u0026rsquo;s Health, 136*(5).\u003c/li\u003e\n\u003cli\u003eOzerdogan, N., et al. (2009). Prevalence and predictors of dysmenorrhea among students at a university in Turkey. *Journal of Women\u0026rsquo;s Health, 107*(1), 39-43.\u003c/li\u003e\n\u003cli\u003eNigussie, A., Asrate, D., \u0026amp; Solomon, H. J. I. J. O. W. S. H. (2016). Primary dysmenorrhea magnitude, associated risk factors, and its effect on academic performance: evidence from female university students in Ethiopia. *Journal of Women\u0026rsquo;s Health, 8*, 489-496.\u003c/li\u003e\n\u003cli\u003eUnsal, A., et al. (2010). Prevalence of dysmenorrhea and its effect on quality of life among a group of female university students. *Journal of Women\u0026rsquo;s Health, 26*(1).\u003c/li\u003e\n\u003cli\u003eElia, F. M., et al. (2018). Lifestyle and prevalence of dysmenorrhea among Spanish female university students. *Journal of Women\u0026rsquo;s Health, 13*(8), e0201894-.\u003c/li\u003e\n\u003cli\u003e\u003cem\u003eMental health of new undergraduate students before and after COVID-19 in China. *Scientific Reports*.\u003c/em\u003e\u003c/li\u003e\n\u003cli\u003eDutra, L., et al. (2020). Modulating Anxiety and Functional Capacity with Anodal tDCS Over the Left Dorsolateral Prefrontal Cortex in Primary Dysmenorrhea. *Journal of Women\u0026rsquo;s Health, 12*, 243-251.\u003c/li\u003e\n\u003cli\u003eHashim, R. T., et al. (2020). Prevalence of primary dysmenorrhea and its effect on the quality of life amongst female medical students at King Saud University, Riyadh, Saudi Arabia. A cross-sectional study. *Journal of Women\u0026rsquo;s Health, 41*(3), 283-289.\u003c/li\u003e\n\u003cli\u003eCakir, M., et al. (2010). Menstrual pattern and common menstrual disorders among university students in Turkey. *Journal of Women\u0026rsquo;s Health, 49*(6), 938-942.\u003c/li\u003e\n\u003cli\u003eHizmetleri, Y. Y. W. T., \u0026amp; Com, I. J. Y. W. T. H. -D. (n.d.). Hosting, Design, Dysmenorrhea Prevalence in Women Who Applied to Gynaecology and Obstetrics Policlinics and Affecting Factors.\u003c/li\u003e\n\u003cli\u003eBhat., A. S. J. I. J. O. M., \u0026amp; Healthence, E. (2013). EFFICACY OF HIJAMAT BILA SHURT (DRY CUPPING) ON PAIN RELIEF IN PRIMARY DYSMENORRHEA. *Journal of Women\u0026rsquo;s Health, 21*(3).\u003c/li\u003e\n\u003cli\u003eMuluneh, A. A., et al. (2018). Prevalence and associated factors of dysmenorrhea among secondary and preparatory school students in Debremarkos town, North-West Ethiopia. *BMC Women\u0026rsquo;s Health, 18*(1), 57.\u003c/li\u003e\n\u003cli\u003eGagua, T., Tkeshelashvili, B., \u0026amp; Gagua, D. J. J. O. T. T. G. G. A. (2012). 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Association of tea drinking and dysmenorrhea among reproductive-age women in Shanghai, China (2013\u0026ndash;2015): a cross-sectional study. *Journal of Women\u0026rsquo;s Health, 9*(4), e026643.\u003c/li\u003e\n\u003cli\u003eFaramarzi, M., \u0026amp; Salmalian, H. J. I. R. C. M. J. (2014). Association of Psychologic and Nonpsychologic Factors With Primary Dysmenorrhea. *Journal of Women\u0026rsquo;s Health, 16*(8).\u003c/li\u003e\n\u003cli\u003eAlia, S. M., Shamssain, M., \u0026amp; Shahwan, M. (n.d.). Prevalence and Impact of Dysmenorrhea on Health-Related Quality of Life in the United Arab Emirates.\u003c/li\u003e\n\u003cli\u003eMonday, I., et al. (2019). Prevalence and Correlation between Diet and Dysmenorrhea among High School and College Students in Saint Vincent and Grenadines. *Journal of Women\u0026rsquo;s Health, 7*(6), 920-924.\u003c/li\u003e\n\u003cli\u003eWrisnijati, D., Wiboworini, B., \u0026amp; Sugiarto, S. J. J. G. d. P. S. (2019). Prevalence and Factor Associated with Severity of Dysmenorrhea Among Female Adolescent in Surakarta. *Journal of Women\u0026rsquo;s Health, 3*(1), 76.\u003c/li\u003e\n\u003cli\u003eRibeiro, J. A., \u0026amp; Jad, A. M. S. J. J. O. A. D. (2010). Caffeine and Adenosine. *Journal of Women\u0026rsquo;s Health, 20 Suppl 1(Suppl. 1), S3.\u003c/li\u003e\n\u003cli\u003eScandinavica, M. \u0026Aring;. J. A. O. e. G. (1979). Pathophysiology of Dysmenorrhea. *Journal of Women\u0026rsquo;s Health, 1979*.\u003c/li\u003e\n\u003cli\u003eNinagawa, T., et al. (1981). Prostaglandins and dysmenorrhea effect of naproxen on prostaglandin concentrations in menstrual blood (author\u0026rsquo;s transl)]. *Journal of Women\u0026rsquo;s Health, 33*(4), 449.\u003c/li\u003e\n\u003cli\u003eClaire, et al. (1986). Caffeine effects on cyclic AMP levels in the mouse embryonic limb and palate in vitro. *Journal of Women\u0026rsquo;s Health, 34*(1), 21-27.\u003c/li\u003e\n\u003cli\u003eOropeza-Rendon, R. L., \u0026amp; Bauer, I. C. (n.d.). Effect of prostaglandin E on the level of camp in bone shape changes marrow macrophages. Inhibition of phagocytosis and cell +. *Journal of Women\u0026rsquo;s Health*.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Primary dysmenorrhea, Female undergraduates, Soft drinks intake","lastPublishedDoi":"10.21203/rs.3.rs-4389961/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4389961/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePrimary dysmenorrhea (PD) is a common global health concern. However, limited studies explored the association between soft drinks intake and PD among female undergraduates in China.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo determine the association between soft drinks (carbonated soft drinks, etc.) as well coffee intake and the incidence/severity of PD among female undergraduates in China.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe performed a cross-sectional study among 1809 female undergraduates in China from September 29, 2020 to October 22, 2020. The demographic information and menstrual information of the participants were collected by a self-administrated questionnaire. Chi-square test, ANOVA test, and logistic regression test were used to investigate the association between soft drinks intake and the incidence/severity of PD. We also conducted stratification analysis among different locations ( rural or urban).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe prevalence of PD was 47.1% (n\u0026thinsp;=\u0026thinsp;852). There were 221 (25.9%) participants suffered from severe pain. In the participants with PD, the OR of carbonated soft drinks intake was 1.244 (95% CI\u0026thinsp;=\u0026thinsp;1.010\u0026ndash;1.533). Among the participants with PD from rural areas, the OR of carbonated soft drinks intake was 1.402 (95% CI\u0026thinsp;=\u0026thinsp;1.045\u0026ndash;1.881), compared with the non-carbonated soft drink group. In the participants with moderate and severe PD, the OR of coffee intake was 0.451 (95% CI\u0026thinsp;=\u0026thinsp;0.228\u0026ndash;0.892), compared with the non-coffee-drinking group. There was a significant association between carbonated soft drinks intake frequency and the severity of PD (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eOur study showed that carbonated soft drinks intake is a risk factor for PD, especially in participants from rural areas. Coffee intake is a protective factor for the severity of PD. Periodical awareness programs about adverse effects of excessive soft drink consumption should be introduced to reduce the prevalence and exacerbation of PD. Coffee intake might be helpful to relieve the severity of PD.\u003c/p\u003e","manuscriptTitle":"Associations between Soft drinks intake and Primary Dysmenorrhea: A Cross-sectional Study among Chinese undergraduate female students","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-30 18:48:27","doi":"10.21203/rs.3.rs-4389961/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-01T09:52:49+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-30T10:14:24+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-14T16:55:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"116460180167855971682569518512196389065","date":"2024-06-06T05:00:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"132503611876078338224100255080855274549","date":"2024-06-03T13:09:43+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-23T20:22:10+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-23T20:09:56+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-05-15T15:28:01+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-05-10T13:04:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-05-08T14:10:53+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"07937cc4-0cf8-4f3c-af14-b0fe49093fe4","owner":[],"postedDate":"May 30th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":32330683,"name":"Health sciences/Health care"},{"id":32330684,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2024-09-16T16:01:44+00:00","versionOfRecord":{"articleIdentity":"rs-4389961","link":"https://doi.org/10.1038/s41598-024-71802-8","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-09-11 15:57:25","publishedOnDateReadable":"September 11th, 2024"},"versionCreatedAt":"2024-05-30 18:48:27","video":"","vorDoi":"10.1038/s41598-024-71802-8","vorDoiUrl":"https://doi.org/10.1038/s41598-024-71802-8","workflowStages":[]},"version":"v1","identity":"rs-4389961","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4389961","identity":"rs-4389961","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}