Analysis of iodine status of monitoring results in high water iodine areas in Henan Province from 2014 to 2015 / 中华地方病学杂志

ABSTRACT

Objective To investigate the consumption rate of non-iodized salt,and evaluate the iodine status and goiter prevalence among school children in high water iodine areas of Henan Province from 2014 to 2015.Methods In the 20 counties with high water iodine,one township was randomly selected from each location (east,west,south,north and middle) in each county;secondly,4 villages were selected from each chosen township;thirdly,15 households were selected to collect salt samples from each chosen village.In the 10 chosen counties,one village with high water iodine was selected and water samples were collected;one school was sequentially selected from the chosen village and 100 school children aged 8-10 were chosen to collect their urine samples and measure their thyroid volume.Salt iodine was tested by semi-quantitative method;iodine contents of urine and water were tested by arsenic cerium catalytic spectrophometry;thyroid volume was measured by ultrasound method.Results In the 20 counties with high water iodine,4 440 salt samples were collected and tested both in 2014 and 2015;the rates of non-iodized salt were 98.2％ (4 363/4 440) in 2014 and 98.3％ (4 366/4 440) in 2015.In the 10 chosen counties,the median water iodine contents from the chosen villages were 202.0 μg/L in 2014 and 235.0 μg/L in 2015;970and 999 urine samples of the students from the chosen villages were collected and tested in 2014 and 2015,and the median urinary iodine contents were 251.9 μg/L in 2014 and 290.6 μg/L in 2015;937 and 948 students were examined in 2014 and 2015,the goiter rates were 3.4％ (32/937) in 2014 and 7.8％ (74/948) in 2015.Stratified by water iodine,the urinary iodine contents and goiter rates of school children increased with the rise of water iodine content.When the water iodine content exceeded 300 μg/L,goiter rate of school children was 8.4％,which was higher than other groups (P ＜ 0.05).Conclusions After stopping the supple of iodized salt in high water iodine areas,the current iodine status and goiter rate of school children are still higher than normal levels.Both noniodized salt supply and water improvement to reduce water iodine content should be taken in the areas with water iodine higher than 150 μg/L.