An investigation on iodine nutritional status of children and pregnant women in Hulunbuir, Inner Mongolia after reduction of salt iodine content

Abstract

Objective To investigate the iodine nutritional status of children and pregnant women in Hulunbuir, Mongolia after reduction of salt iodine content, and to provide theoretical bases for scientific iodine supplementation. Methods In May to October 2018, according to Inner Mongolia Deficiency Disorders Surveillance Project (2016), in 14 banners (cities, districts) of Hulunbuir, each banner (city, district) was divided into 5 sampling areas according to the location of east, west, south, north and middle, and 40 non-boarding children aged 8-10 years old (age matched, half male and half female) and 20 pregnant women were selected. Salt samples and urine samples were collected to detect salt and urinary iodine levels. Salt iodine was detected based on the General Test in Salt Industry-Determination of Iodine (GB/T 13025.7-2012), and urinary iodine was detected based on the Method for Determination of in Urine by As3+-Ce4+ Catalytic Spectrophotometry (WS/T 107-2009), the iodine nutritional status was determined according to the standards of urinary iodine recommended by WHO/UNICEF/ICCIDD. At the same time, the goiter condition of children was examined by B-ultrasound. Results A total of 4 018 salt samples from homes of children and pregnant women were collected, the median of salt iodine was 22.61 mg/kg, the iodized salt coverage rate was 94.50% (3 797/4 018), the qualified rate of iodized salt was 96.92% (3 680/3 797), and the consumption rate of qualified iodized salt was 91.59% (3 680/4 018). A total of 2 790 urine samples from children were collected, the median of urinary iodine was 179.15 μg/L; and 1 228 urine samples from pregnant women were collected, the median of urinary iodine was 156.88 μg/L. There were 9 banners (cities, districts) where children were at the iodine appropriate level, 4 banners (cities, districts) were higher than the iodine appropriate level and 1 banner was at iodine excessive level. There were 4 banners (cities, districts) where pregnant women were at the iodine deficiency level, 8 banners (cities, districts) were at the iodine appropriate level and 2 banners (cities) were higher than the iodine appropriate level. A total of 2 629 children were examined thyroid gland, and the goiter rate was 0.99% (26/2 629). Conclusions After reduction of salt iodine content, the iodine nutrition of children and pregnant women in Hulunbuir is generally at an appropriate level. In some banners (cities, districts), children and pregnant women are at iodine deficiency level, iodine over appropriate level or iodine excessive level. nutrition monitoring measures of children and pregnant women should be strengthened. Key words: Child; Pregnant women; Iodine; Salts; Urine