1. Associations between iodine intake, thyroid volume, and goiter rate in school-aged Chinese children from areas with high iodine drinking water concentrations.
- Author
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Wen Chen, Xiang Li, Yalan Wu, Jianchao Bian, Jun Shen, Wen Jiang, Long Tan, Xiaoming Wang, Wei Wang, Pearce, Elizabeth N., Zimmermann, Michael B., Carriquiry, Alicia L., and Wanqi Zhang
- Subjects
IODINE ,THYROID gland physiology ,CHILDREN ,GOITER ,IODINE in the body ,CONTAMINATION of drinking water ,THYROID hormone synthesis ,HEALTH ,DISEASE risk factors ,PHYSIOLOGY ,WATER supply ,ANTHROPOMETRY ,CHI-squared test ,CHILDREN'S health ,CHILD nutrition ,CLINICAL trials ,CONFIDENCE intervals ,NUTRITIONAL assessment ,NUTRITION policy ,NUTRITIONAL requirements ,PROBABILITY theory ,REGRESSION analysis ,RESEARCH funding ,STATISTICS ,ADOLESCENT health ,THYROID gland ,ADOLESCENT nutrition ,LOGISTIC regression analysis ,DATA analysis ,CROSS-sectional method ,DATA analysis software ,DESCRIPTIVE statistics ,ODDS ratio ,MANN Whitney U Test - Abstract
Background: Excessive iodine intake may have adverse effects on the thyroid, particularly in children, but the safe upper iodine intake concentration in children is unclear. Objective: We assessed the adverse effects of high iodine intake from iodine-rich drinking water on thyroid size in children by examining associations between thyroid volume (Tvol), total goiter rate (TGR), and iodine intake. Design: In a multistage cross-sectional survey, we collected two 24-h urine samples on 2 nonconsecutive days and determined 24-h urinary iodine excretion, then calculated habitual daily iodine intake. Ultrasonographic Tvol was measured, and TGR was calculated based on international and Chinese reference ranges for Tvol in children. Results: This study included 2089 children from Shandong province, where the median (IQR) drinking water iodine concentration was 183 mg/L (69-406 mg/L). The median (IQR) 24-h urinary iodine concentrations for the 2 collections were 381 mg/L (203-649 mg/L) and 398 mg/L (202-687 mg/L), respectively. The median (IQR) habitual daily iodine intake of children was 298 mg/d (186-437 mg/d). Tvols were slightly higher in boys than in girls (P = 0.035). The overall TGR was 9.7% and did not differ by sex. The TGR was ~5% for children aged 7-10 and 11-14 y at iodine intakes of 200-249 and 250-299 mg/d, respectively. With the use of logistic regression and 2-step linear regression, a nonlinear association was observed between Tvol, TGR, and iodine intake, with a threshold intake of 150 mg/d. Conclusions: Tvol begins to increase in children when iodine intake is $ 150 mg/d, and the TGR exceeds 5% when daily iodine intake is $250 mg/d for children aged 7-10 y and $300 mg/d for children aged 11-14 y. Our findings suggest that 150-249 and 150-299 mg/d seem to be safe upper iodine intake ranges for children aged 7-10 and 11-14 y, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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