Iodine nutritional status of key population and its correlation with water iodine and salt iodine in Hainan Province / 中华地方病学杂志

ABSTRACT

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.