To determine whether median urinary iodine concentration of school-aged children is an appropriate indicator of iodine nutritional status in pregnant women, lactating women, childbearing age women and adult men and women.
Datasets included are the Chinese National Iodine Deficiency Disorders Surveys (2011 and 2014), the Iodine Nutrition Survey in Coastal Provinces (2009) and the High Iodine Deficiency Risk Areas Survey (2009-2014). Population groups in these surveys included school-aged children, pregnant women, lactating women, childbearing age women and adults. The median urinary iodine concentration of school-aged children was matched with other population groups at the county level.
Weak or moderate correlation was observed of median urinary iodine concentration between school-aged children and pregnant women, and lactating women in both national and provincial surveys. However, the agreement appeared to be stronger between school-aged children and childbearing age women, and adult men and women.
The study confirms that median urinary iodine concentration of school-aged children is not a good indicator for iodine nutrition status of pregnant women and lactating women compares to adults, including childbearing age women. Median urinary iodine concentration of school-aged children can be used as a tool for assessing iodine nutrition in adult population other than pregnant and lactating women. Level of data aggregation, sample size at each level, and the environmental iodine level in the areas may influence the results.