Abstract: Objective To understand the iodine nutritional level of children aged 8-10 years and pregnant women in Nantong City from 2021 to 2023,and to provide scientific evidence for adjusting the prevention and control measures of iodine deficiency disorders. Methods Using multi-stage stratified random sampling,7 counties（cities,districts） in Nantong City were divided into 5 districts each year to collect salt and urine samples from two groups of people and test their levels. Children were also examined for thyroid status. Results A total of 6 300 household salt samples were collected from 2021 to 2023,with a median salt iodine concentration of 24.59 mg/kg. The coverage rate of iodized salt was 94.97%,the qualification rate of iodized salt was 95.94%,and the consumption rate of qualified iodized salt was 91.11%. A total of 4 200 urine samples from children were collected,with a median urinary iodine level of 188.40μg/L. The proportions of urine iodine values <100 μg/L and ≥300 μg/L were 16.4% and 16.93%,respectively. A total of 2 100 urine samples from pregnant women were collected,with a median urinary iodine level of 131.92 μg/L. There were statistically significant differences in urine iodine levels among different pregnancy stages（H=17.502,P<0.01）. Thyroid conditions of 1 400 children were examined by ultrasound,with a goiter rate of 1.57% and a detection rate of thyroid nodules of 8.50%. Conclusion From 2021 to 2023,all indicators in Nantong City met the standards for the elimination of iodine deficiency disorders. The overall iodine nutritional status of children was suitable,with a risk of both iodine deficiency and excess in some children. The iodine nutritional status of pregnant women was slightly below the appropriate level. The health department should continue to monitor the iodine nutritional status of key populations,combining scientific iodine supplementation with precise supplementation as the educational and promotional concept,implementing multiple measures to sustain the elimination status of iodine deficiency disorders in our city.

Key words: Iodine deficiency disorders, Iodine nutrition, Children and pregnant women, Salt iodine, Urine iodine