Iodine Nutritional Status and Thyroid volume of School-Aged Children in Wuhan, central of China

Background: /Aims: Iodine deficiency is a public health problem over the world. China has achieved the iodine deficiency disorders (IDD) elimination goal through a mandatory universal salt iodization (USI) program. The aim of this study is to assess the current iodine nutritional status and thyroid volume of school-aged children in Wuhan, central of China. Methods The cross-sectional study was conducted among 8–10 years old children from 5 districts in Wuhan. A total of 1000 students were investigated. Salt iodine concentrations, urine iodine concentrations were determined using the standardized methods recommended by WHO/ICCIDD. An ultrasonography of thyroid and anthropometric measurements were performed in all subjects. Results The median urinary iodine concentration(MUI) of students was 247.50 µg/L with interquartile range of 147.00 to 384.00 µg/L. Two districts were classified as regions with adequate iodine nutrition, two districts as regions above the requirement, and one district as a region excessive according to the MUI. The prevalence of goiter was 3.0% and 7.8% according to Chinese national and WHO reference values, respectively, and the difference was not observed among different iodine nutrition groups(P༞0.05). The median thyroid volume(Tvol) of all students was 2.56 ml and the P97 of thyroid volume of both male and female in our study was generally higher than that reported by WHO/ICCIDD in 2007 as a function of age and BSA. The Tvol was in significant association with age, height, weight and BSA by Spearman’s correlation analysis(P < 0.001),and the result of multivariate linear regression analysis showed that only BSA were found to have a significant effect on thyroid volume after log conversion (t = 13.437, P < 0.001). Conclusion The present study indicated that the iodine nutrition among school-aged children in Wuhan was generally adequate with a relatively low goiter rate, while some of them have excess iodine nutrition. Thyroid volume in our study was higher than the reference of WHO and showed a significant correlation with BSA. So further researches were needed to evaluate the thyroid function in children with iodine excessive and the applicability of WHO reference in goiter diagnose. It was also highly recommended to establish the local reference values for thyroid volume that might be applicable to precisely define goiter prevalence in Wuhan.