Analysis of the focus groups' iodine nutritional status after implementation of a new standard of salt iodization

Objective To know the focus groups' iodine nutrition level after implementation of a new standard of salt iodization, and to provide technical support for iodine deficiency disorders (IDD) prevention in Nanping City. Methods According to the requirements of "Focus Groups' Iodine Nutrition and Related Health Monitoring Program in Fujian Province", Yanping, Jian'ou, Zhenghe, Jianyang and Shaowu counties (cities, districts) were selected for monitoring in 2014; Pucheng, Songxi, Wuyishan, Shunchang and Guangze counties (cities, districts) were selected for monitoring in 2015. We studied: ①The water iodine: 2 tap water samples were collected from centralized water supply system; from decentralized water supply system, 2 residents drinking water samples were collected according to each of five directions of east, west, south, north, and center, for determination of water iodine content. ②Salt iodine: 4 administrative villages (neighborhood committees) were selected from each monitoring site, from which 15 households were selected, edible salt samples were collected, and salt iodine content was tested. ③ Urinary iodine: one primary school was selected from each monitoring site, 30-40 students aged from 8-10 years old were selected from each primary school, urine samples were collected for detecting urinary iodine. ④Salt intake per capita: among the 8-10 years old students whom had been collected urine samples, 10 students' family edible salt samples were collected, then the salt intake per capita was measured via 3-days weighing method. ⑤ Goiter: in Jianyang and Shaowu Cities in 2014, and in Guangze and Shunchang Cities in 2015, the thyroid volume was measured using ultrasound, and goiter rate was calculated of 8-10 years old students whom had been collected urine samples before. ⑥Pregnant women urinary iodine: 20 pregnant women (early, middle and late pregnancy were included) were selected in each monitoring site, urine samples were collected for detecting urinary iodine. Results Investigation results in 2014 and 2015 were as follows: 61 and 50 samples of daily drinking water of the two years were investigated, the medians of drinking water iodine were 1.5 and 5.7 μg/L for each group of samples, respectively; and daily salt intake of 253 and 250 residents of the two years were investigated, and the medians intake were 6.8 and 6.9 g/d, respectively; 1 500 and 1 500 residential edible salt samples in the two years were tested, iodized salt coverage rates were 99.7% (1 496/1 500) and 99.9% (1 498/1 500), respectively, qualified rates of iodized salt were 95.7% (1 431/1 496) and 94.5% (1 416/1 498), respectively, qualified iodized salt consumption rates were 95.4% (1 431/1 500) and 94.4% (1 416/1 500), respectively; of which 749 and 1 000 8-10 years old children's urinary iodine were also tested, and children's urinary iodine medians were 190.1 and 210.4 μg/L, respectively; 300 and 275 thyroids of children aged from 8 to 10 were tested, and goiter rates (ultrasound method) were 1.3% (4/300) and 2.9% (8/275), respectively; 500 and 500 pregnant women urinary iodine were tested in the two years, and pregnant women urinary iodine medians were 133.2 and 150.3 μg/L, respectively, the pregnant women urinary iodine median of the Nanping City of 10 counties (cities, districts) and 7 counties (cities, districts) were less than 150 μg/L. Conclusions Nanping City's natural environment iodine is deficient. After the new standard of salt iodization, we can continue to promote the process of the standard of eliminating IDD in China, besides, 8-10 years old children's iodine nutrition is basically at the appropriate level, but the level of pregnant women has showed a slightly deficiency. Key words: Iodine; Nutrition; Urine; Child; Pregnant women