National monitoring results in high water iodine areas in 2015

Abstract

Objective To observe the high iodine induced thyroid goiter condition, iodine nutritional status and coverage rate of non-iodized salt in high water iodine areas. Methods The household non-iodized salt was monitored in counties (cities, regions) of high water iodine areas and high iodine diseased areas in Tianjin, Hebei, Shanxi, Jiangsu, Anhui, Shandong, Henan and Shaanxi provinces. Among the monitoring sites, where the water iodine were 150-300 μg/L or higher than 300 μg/L, 50% of the them were selected to investigate the water iodine, children urinary iodine and thyroid volume of children in high iodine counties. Results Household edible salt was monitored in 110 counties of 8 provinces, with a total of 25 597 salt samples. The number of non-iodized salt was 24 640, and the coverage rate of non-iodized salt was 96.3%. After being weighted based on the population of counties, the coverage rate of non-iodized salt was 96.9%. In all, 73 survey areas include 183 663 people, 64 monitoring sites (87.7%) where the water iodine level were higher or equal to 150 μg/L and the median of water iodine was 250.8 μg/L. Totally 5 991 children aged 6-12 were measured thyroid volume, the total goiter rate was 6.2%, the children thyroid goiter rate was higher than 5% in Hebei, Shanxi, Henan, Tianjin and Shandong provinces. Totally 4 618 children were detected urinary iodine, the median urinary iodine concentration was 373.0 μg/L, and the children median urinary iodine concentration was exceeded 300 μg/L in Tianjin, Hebei, Shanxi, Jiangsu and Shandong provinces. The children urinary iodine concentration and goiter rate increased gradually with increasing of water iodine content. Conclusions The non-iodized salt coverage rate is high in high water iodine areas, most monitored areas have changed drinking water sources, but the median water iodine concentration is still higher than 150 μg/L. Children median urinary iodine concentration is higher than 300 μg/L, iodine is in a excessive status. The children total goiter rate is higher than 5%. Some countermeasures are proposed to search low iodine water, change water sources, do health education, and add other surveillance measures, such as thyroid function detection on target groups, and so on. Key words: Drinking water; Iodine, excess; Urine; Goiter