An investigation of iodine nutritional status of children aged from 8 - 10 and pregnant women before and after adjustment of salt iodine concentration in Xiamen City / 中华地方病学杂志

ABSTRACT

Objective:To investigate the iodine nutritional status among children aged from 8 - 10 and pregnant women in Xiamen City before and after adjustment of salt iodine concentration, and scientifically evaluate the suitability of the new standard iodized salt adjustment policy for Xiamen City.Methods:In the pre-adjustment period (2011) and the post-adjustment period (2018), cross-sectional research methods and stratified cluster sampling methods were adopted in six districts of Xiamen City. The salt samples of residents and pregnant women, urine samples of children aged from 8 - 10 and pregnant women were collected to determine the iodine level; thyroid of children aged from 8 - 10 was examined. Changes in salt iodine, urine iodine and goiter prevalence before and after adjusting iodine content of salt were compared.Results:The median of salt iodine in residents after the adjustment (23.5 mg/kg) was significantly lower than that of before (28.9 mg/kg, Z = - 10.512, P < 0.05), the median of salt iodine in pregnant women after the adjustment (23.7 mg/kg) was significantly lower than that of before (29.2 mg/kg, Z = - 12.622, P < 0.05); the consumption rate of qualified iodized salt in residents after the adjustment (95.7%, 1 196/1 250) was significantly lower than that of before (97.1%, 1 608/1 656; χ 2 = 4.250, P < 0.05); before and after adjustment of salt iodine concentration, the consumption rate of qualified iodized salt in pregnant women was 94.7% (124/131) and 95.9% (579/604), respectively. No significant difference was found when comparing the consumption rate of qualified iodized salt in pregnant women (χ 2 = 0.015, P > 0.05). There was significant difference in median urinary iodine (from 204.2 to 183.9 μg/L, detected in 652, 1 250 urine samples, respectively) of children aged 8 - 10 years ( Z = - 3.583, P < 0.05); the difference of iodine nutritional status in pregnant women before and after adjustment of salt iodine concentration(130.2, 130.8 μg/L, detected in 132, 604 urine samples, respectively) was not significant ( Z = - 1.715, P > 0.05). The thyroid goiter rate of children aged 8 - 10 years had reduced from 1.1% (14/1 239) to 0.2% (2/1 253), the difference was statistically significant (χ 2 = 9.195, P < 0.05). Conclusions:As a whole, the measure of control and prevention of iodine deficiency disorders through iodized salt is implemented well in Xiamen City. After adjustment of salt iodine concentration, the iodine status of children aged from 8 to 10 is adequate, but the pregnant women has showed iodine deficiency.