PD197 - IODINE NUTRITIONAL STATUS AND THYROID DISORDERS AMONG SCHOOL-AGE CHILDREN IN REGIONS WITH DIVERSE WATER IODINE LEVELS IN CHINA

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PD197

IODINE NUTRITIONAL STATUS AND THYROID DISORDERS AMONG SCHOOL-AGE CHILDREN IN REGIONS WITH DIVERSE WATER IODINE LEVELS IN CHINA

Y. Zhang1,*

1Chinese Center for Disease Control and Prevention National Institute for Nutrition and Health, Beijing, China

 

Rationale: Water iodine (WI) primarily determines iodine status. This study evaluates the impact of varying WI on iodine nutrition and thyroid disorders in Chinese school-age children to support site-specific intervention strategies.

Methods: A cross-sectional survey was conducted among school-age children in three regions categorized by WI: Low (14.9 μg/L), Adequate (49.9 μg/L), and High (233.8 μg/L). Urinary iodine concentration was measured using Sandell–Kolthoff method. Thyroid volume were assessed via ultrasonography. Thyroid disorders were diagnosed based on abnormal serum levels of thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), and/or thyroid antibodies (TPOAb/TgAb). 

Results: Among 1,507 included children, Median Urinary Iodine (MUI) increased significantly with WI levels (P < 0.001), reaching 738.1 μg/L in the High WI group, indicating iodine excess. The prevalence of goitre followed a U-shaped distribution, being lowest in the Adequate group (1.4%) and significantly higher in the Low (7.5%) and High (9.9%) groups (P < 0.001). Crucially, the overall prevalence of thyroid disorders—encompassing functional abnormalities and positive antibodies—showed a sharp dose-response relationship with WI, rising from 7.3% in the Low group to 40.8% in the High group (P < 0.001).

Group (WI)

MUI(μg/L)

Goitre (%)

Thyroid disorders（%）

Low

146.0(111.2)

36(7.5)

35(7.3)

Adequate

217.2(132.2)

7(1.4)

87(17.0)

High

738.1(611.6)

51(9.9)

211(40.8)

Conclusion: Both iodine deficiency and excess in drinking water are associated with increased goitre risk. However, high water iodine levels significantly escalate the overall burden of thyroid dysfunction and autoimmunity. These findings underscore the urgent need for precision iodine monitoring and "one size does not fit all" intervention policies in areas with varying water iodine backgrounds.

Disclosure of Interest: None declared