Analysis of survey results of iodine deficiency disorders and water iodine in Wuhan City in 2017

Abstract

Objective To understand the household consumption of iodized salt, iodine nutrition status and water iodine status in after implementation of the new iodized salt standard, in order to provide a new scientific basis for prevention and control of iodine deficiency disorders. Methods In 2017, in 13 districts of Wuhan, each district was divided into five sampling areas by east, west, south, north and middle, and one town/street was selected in each district, 20 pregnant women and 40 students aged 8-10 years old (half males and females) from one non-boarding elementary school were selected, to collect salt samples from their home. iodine was detected by the Salt Industry General Test Method for Determination of Iodine (GB/T 13025.7-2012). According to Wuhan City's 2017 Endemic Disease Prevention and Control Work Plan, urine samples of children aged 8-10 years old and pregnant women were collected in 8 districts of Wuhan, and urinary iodine levels were tested using the Arsenic and Cerium Catalyzed Spectrophotometric Method for Determination of Urinary Iodine (WS/T 107-2006). Goiter of children aged 8-10 years old was examined by B-ultrasonography in 5 districts of Wuhan. Water iodine survey was conducted in 13 districts based on township/street, and water iodine was tested via the arsenic and cerium catalyzed spectrophotometric method (GB/T 5750.5-2006). Results A total of 3 900 edible salt samples were tested, the median of salt iodine was 23.69 mg/kg, the coverage rate of iodized salt was 98.82% (3 854/3 900), the consumption rate of eligible iodized salt was 95.03% (3 706/3 900). A total of 1 600 urine samples of children were collected, and the median of children's urinary iodine was 267.00 μg/L. A total of 800 urine samples of pregnant women were collected, and the median of pregnant women's urinary iodine was 182.00 μg/L. A total of 1 000 children were monitored their thyroid gland, with a goiter rate of 1.9% (19/1 000). A total of 218 water samples were collected, the median of water iodine was 2.90 μg/L (below national standards of 10-100 μg/L). Conclusions After adjustment of new iodized salt standards in Wuhan, the iodine nutrition status of children and pregnant women are good. However, due to low water iodine content, the geographical environment of still belongs to iodine-deficient area. Therefore, it should continue to implement the salt iodization policy and strengthen the monitoring of iodine nutrition in key populations such as children and pregnant women. Key words: Iodine; Salts; Urine; Goiter; Water