Analysis of monitoring results of iodine deficiency disorders in Hubei Province in 2016

Objective To analyze the status of iodine nutrition after implementing new standard of iodized salt in Hubei Province, and to evaluate the effectiveness of prevention and control measures. Methods In 2016, in 103 counties (cities, districts) of Hubei Province, the townships (streets) under the jurisdiction of each county (city, district) were divided into five regions: east, south, west, north, and middle. One township (street) was selected from each region, and one primary school was selected from each township(street). From each primary school 40 children aged 8 - 10 (half males half females) were selected to collect salt samples from their households. Twenty pregnant women from townships(streets) near the selected schools were chosen to collect edible salt samples from their households. According to the method of population proportionate sampling (PPS), 35 counties (cities, districts) were chosen from 103 counties (cities, districts). Thyroid volume of children aged 8 - 10 was examined, and urinary iodine of children and pregnant women were tested. Iodine nutrition criteria: the median urinary iodine of children < 100 μg/L is iodine deficiency, 100 - < 200 μg/L is iodine appropriate, 200 - < 300 μg/L is iodine overdose, ≥300 μg/L is iodine excess; pregnant women urinary iodine median < 150 μg/L is iodine deficiency, 150 -< 250 μg/L is iodine appropriate, 250 - < 500 μg/L is iodine overdose, and ≥500 μg/L is iodine excess. Results Totally 30 967 edible salt samples from children's and pregnant women's households were examined, and the median of salt iodine was 23.85 mg/kg. The coverage rate of iodized salt was 99.46% (30 799/30 967) , the consumption rate of qualified iodized salt was 94.00% (29 108/30 967). Totally 6 789 children aged 8 - 10 were examined thyroid volume and detected urinary iodine, the goiter rate was 0.85% (58/6 789) and the median urinary iodine was 263.54 μg/L. Totally 3 348 urine samples of pregnant women were examined, and the median urinary iodine was 166.71 μg/L. Conclusions The salt iodine content of residents and the goiter rate of children in Hubei Province meet the national standard for eliminating iodine deficiency disorders. The iodine nutrition level of children and pregnant women is iodine appropriate or iodine overdose. The iodine nutrition level monitoring of key populations should be continuously strengthened. Key words: Iodine; Deficiency disease; Salts; Urine; Goiter