Comparison of iodine nutritional status and disease monitoring results among children in water source high iodine areas of Henan Province in 2017 and 2019 / 中华地方病学杂志

ABSTRACT

Objective:To compare the coverage rate of non-iodized salts, children's iodine nutrition and the change trend of goiter rate between the original water source high iodine areas in Henan Province in 2017 and the newly designated water source high iodine areas in 2019.Methods:Using a cross-sectional survey method, household edible salt monitoring was conducted in all 20 counties (cities, districts) with high iodine content in Henan Province in 2017. Ten counties (cities, districts) were selected to monitor water iodine, urinary iodine and thyroid volume of children aged 8 to 10 years. A total of 4 430 salt samples and 1 012 urine samples were collected, and thyroid volume of 1 012 children were measured. In 2019, monitoring of household edible salt, water iodine, urinary iodine, and thyroid volume was carried out in all 55 newly designated counties (cities, districts) with high iodine village. A total of 9 835 salt samples and 9 830 urine samples were collected, and the thyroid volume of 8 896 children was measured. The monitoring results of two years were compared, and the relationship between children's urinary iodine and goiter rate was analyzed by univariate logistic regression.Results:In 2019, the water iodine content in newly designated high iodine areas decreased compared to the original high iodine areas in 2017 (119.8 to 191.0 μg/L), and the difference was statistically significant ( Z = - 2.48, P = 0.013). The rate of non-iodized salts in 2019 was only 35.5% (3 494/9 835), significantly lower than that in 2017 (96.2%, 4 263/4 430, χ 2 = 4 536.74, P < 0.001). The median urinary iodine of children in 2017 and 2019 were 338.2 and 317.8 μg/L, respectively, the difference between the two years was statistically significant ( Z = - 2.46, P = 0.014). In 2017 and 2019, the goiter rate of children aged 8 to 10 years was 1.5% (15/1 012) and 2.1% (187/8 896), respectively, and there was no significant difference between the two years (χ 2 = 1.76, P = 0.185). The results of univariate logistic regression analysis showed that, compared with the control group with urinary iodine < 100 μg/L, the risk of goiter rate (but the enlargement rate did not exceed 5%) increased with the increase of urinary iodine level (100 - 199, 200 - 299 and ≥300 μg/L groups), and the differences were statistically significant [odds ratio ( OR) = 8.64, 7.68, 10.69, P < 0.05]. Conclusion:After the implementation of the new demarcation standard for areas with excessive iodine in water sources, the supply of non-iodized salts in Henan Province is relatively lagging behind, and the iodine nutrition level of children is still high, but the goiter rate is relatively stable.