Analysis of monitoring results in water source high iodine areas in Taiyuan City, Shanxi Province from 2012 to 2017 / 中华地方病学杂志

ABSTRACT

Objective:To investigate the status of removing iodized salt, water iodine, and iodine nutrition of children in water source high iodine areas in Taiyuan City, Shanxi Province, so as to provide basis for the implementation of prevention and control measures in high iodine areas according to local conditions.Methods:From 2012 to 2017, four administrative villages were selected from each of the high iodine townships in the water source high iodine areas (Qingxu County and Xiaodian District) in Taiyuan City, and 15 households in each administrative village were sampled for salt iodine detection by semi quantitative method. According to the "National Monitoring Program for Water Source High Iodine Areas (Trial)" (2012 edition), 1-2 high iodine villages were selected respectively in Qingxu County and Xiaodian District every year as monitoring sites, and grouped by water iodine of 150-300 μg/L and > 300 μg/L. If the monitoring site had been implemented the water improvement project, one tap water sample shall be collected. Whereas, if the monitoring site had not been implemented the water improvement project, two drinking water samples shall be collected from each household in the five directions of east, west, south, north and middle, and the water iodine shall be detected using the "Research on Methods for Water Iodine Testing in Iodine Deficiency and High Iodine Areas" recommended by the National Iodine Deficiency Disorders Reference Laboratory of the Chinese Center for Disease Control and Prevention. A total of 100 children aged 8-10 years old were selected from village primary schools or central primary schools in townships where the monitoring sites were located, and their thyroid volume was detected by B-ultrasound; urine samples were taken from more than 30 children and urinary iodine was detected by arsenic-cerium catalytic spectrophotometry.Results:From 2012 to 2017, the rate of non-iodized salt in Qingxu County ranged from 91.7% (165/180) to 96.1% (173/180); the rate of non-iodized salt in Xiaodian District were all 100.0% (120/120). A total of 52 water samples were tested, and the median water iodine was 282.3 μg/L, ranged from 121.1 to 546.3 μg/L. A total of 1 401 children's thyroid were examined, and the goiter rate was 7.5% (105/1 401). A total of 597 children's urine samples were tested, and the median urinary iodine was 458.1 μg/L, ranged from 21.0 to 1 778.7 μg/L. The median urinary iodine (327.1 μg/L) and goiter rate (4.9%, 34/697) of children in the 150-300 μg/L water iodine group were compared with those in the > 300 μg/L water iodine group (552.9 μg/L; 10.1%, 71/704), the differences were statistically significant ( Z = - 8.934, χ 2 = 13.698, P < 0.01). Conclusions:From 2012 to 2017, the median water iodine is 282.3 μg/L in water source high iodine areas in Taiyuan City, the status of removing iodized salt is good (the rate of non-iodized salt > 90%). However, children have excessive iodine (median urinary iodine ≥300 μg/L) and goiter rate (> 5%). It is suggested that the main measures should be taken to improve water quality and reduce iodine content in drinking water in water source high iodine areas, continuously monitor water iodine, and timely adjust the prevention and control measures according to the change of water iodine.