A Comparison of Iodine Status in Children and Pregnant Women After a Policy Change in the Iodized Salt Standard in Shanghai, China
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In Shanghai, a new iodized salt standard was implemented in 2012. To provide evidence to the government, we compared iodine status before (35 mg/kg) and after (30 mg/kg) adjustment in vulnerable populations living in Shanghai. The probability-proportional-to-size sampling technique was used to select at least 360 pregnant women for urine iodine test and at least 1200 students for thyroid measurement and the household salt test. Of these students, at least 360 performed urine iodine test. The median thyroid volume and the median household salt iodine concentration of children aged 8–10 years were 1.80 ml and 24.8 mg/kg in 2015, and 0.97 ml and 28.3 mg/kg in 2011. The median urine iodine concentration (UIC) of pregnant women was 126.52 and 139.77 μg/L in 2015 and 2011. All differences were statistically significant (P < 0.05). The median UIC of students was 171.40 and 181.63 μg/L in 2015 and 2011, the difference was not statistically significant. Multivariate linear regression analysis showed that thyroid volume in children was associated with sex, age, region, and household salt iodized concentration. The current iodized salt concentration meets the basic needs of the population’s iodine requirements except for pregnant women. Periodic monitoring is necessary particularly in vulnerable groups.
KeywordsIodine status Urine iodine Thyroid volume Children Pregnant women
We thank all the children and pregnant women who participated in this study. We also thank the healthcare professionals at the Centers for Disease Control and Prevention of the 17 districts in Shanghai for their assistance.
The current study was supported by the National Nature Science Foundation of China (No. 81602851), Excellent Young Talents of Health System in Shanghai (No. 2017YQ043), the Fourth Three-Year Public Health Program (No. GWIV-27.1), and Key Disciplines (No. 15GWZK0801). None of the above funders played a role in the study design, data analysis or manuscript writing.
Conceived and designed the experiments: Shoujun Liu, Xiaohui Su, and Peng Liu; Performed the experiments: Shurong Zou, Jun Song, and Zhengyuan Wang; Analyzed the data: Zhengyuan Wang; Wrote the paper: Zhengyuan Wang. All authors read and approved the final version of the manuscript.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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