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Objective:To understand the iodine nutritional status of key population and its correlation with water iodine and salt iodine in Hainan Province, and to provide scientific basis for iodine supplement.Methods:According to the "National Water Iodine Content Survey Program for Drinking Water" and the "National Iodine Deficiency Disorders Surveillance Program (2016)", surveys on water iodine and iodine nutritional status of key populations in 21 cities (counties, districts) in Hainan Province in 2017 and 2018 were conducted. Water samples, urine samples at random and home salt samples of children aged 8 - 10 years old and pregnant women were collected to detect water iodine, urinary iodine and salt iodine. At the same time, the thyroid volume of children was measured by B-mode ultrasound, and the goiter rate was calculated. According to the geographical location, Hainan Province was divided into 3 areas: central mountainous, western coastal and eastern coastal, the results of water iodine, salt iodine and urinary iodine in different areas were compared and analyzed. Water iodine was detected by "Water Iodine Detection Method Suitable for Iodine Deficiency and High Iodine Areas" recommended by National Reference Laboratory for Iodine Deficiency Disorders; urinary iodine was detected by arsenic cerium catalytic spectrophotometry; salt iodine was detected by direct titration.Results:A total of 2 566 water samples were detected, and the median water iodine was 6.0 μg/L. A total of 4 220 urine samples of children were detected, the median urinary iodine was 170.0 μg/L (appropriate range was 100 - 199 μg/L), the goiter rate was 0.09% (4/4 220). A total of 2 124 urine samples of pregnant women were detected, the median urinary iodine was 120.7 μg/L (appropriate range was 150 - 249 μg/L). A total of 6 344 salt samples were detected, coverage rate of iodized salt, qualified rate of iodized salt and consumption rate of qualified iodized salt were 97.76% (6 202/6 344), 97.47% (6 045/6 202), and 95.29% (6 045/6 344), respectively. In central mountainous, western coastal and eastern coastal areas, medians water iodine were 3.3, 6.5, and 6.5 μg/L, respectively, the difference was statistically significant ( H = 13.721, P < 0.01); the consumption rates of qualified iodized salt were 97.86% (1 833/1 873), 90.52% (1 613/1 782), and 96.65% (2 599/2 689), respectively, the difference was statistically significant (χ 2 = 71.217, P < 0.01); the medians urinary iodine of children were 182.4, 160.1, and 167.4 μg/L, respectively; the medians urinary iodine of pregnant women were 120.1, 117.7, and 103.9 μg/L, respectively. There was a positive correlation between urinary iodine in children and pregnant women and salt iodine ( r = 0.394, 0.657, P < 0.05). Conclusions:The iodine nutrition of children in Hainan Province is generally at an appropriate level, and pregnant women are at risk of iodine deficiency. There is a positive correlation between urinary iodine in children and pregnant women and salt iodine. The prevention and treatment of iodine deficiency disorders should focus on strengthening iodine nutrition monitoring of pregnant women.
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Objective To grasp the distribution of iodine in drinking water in the environment of Hainan Province,and provide scientific basis for prevention and treatment of iodine deficiency disorders.Methods In 2017,in all cities (counties,districts) in Hainan Province,townships were used as units to collect water samples to detect iodine content according to their different water supply methods.In the townships with median drinking water iodine ＞ 10 μg/L,the administrative village (neighborhood committee) was used as a unit to collect water sample to detect iodine content.According to the geographical location (central mountainous area,eastern coast,western coast),water source type (tap water,intubation well,spring water),and well depth,the distribution of water iodine was analyzed.Results A total of 2 566 water samples were detected in 21 cities (counties,districts),the median water iodine was 6.0 μg/L,range was 0.1-150.6 μg/L,the median water iodine of all cities (counties,districts) was ＜ 10 μg/L.The median water iodine in the central mountainous area,eastern coast,and western coast were 3.3,6.5,6.5 μg/L,respectively;tap water,intubation well,and spring water were 5.6,6.4,1.3 μg/L,respectively;0-,100-,200-,≥300 m well depth were 6.6,5.1,4.2,and 1.5 μg/L,respectively.The water iodine content range was 0.2-17.9 μg/L in 230 townships in the province,there were 12 townships with the median water iodine ＞ 10 μg/L,including 133 administrative villages (neighborhood committees),and 737 water samples were detected,the water iodine content range was 1.0-37.1 μg/L.Conclusions All cities (counties,districts) in Hainan Province belong to iodine deficiency areas,the central mountainous area is even more serious.Most of the townships in the province are in iodine deficiency.No administrative villages (neighborhood committeea) with high iodine have been found.The province should continue to implement salt iodization to prevent and treat iodine deficiency disorders.