Assessment of the Iodine Status of the Wa National Boarding School Students in Southwest China

Iodine deficiency disorder (IDD) has been recognized as a major public health problem worldwide and has serious detrimental effects on the growth and development of the children. Therefore, monitoring the iodine status of the school-aged children is of great importance. We randomly recruited 159 boarding school students (aged from 6 to 14) from 10 primary schools in Lincang County, Yunnan Province. The dietary iodine level of the students was measured by the new mixed meal method and chemical analysis. Fifty-seven daily water samples and 32 salt samples were collected from the same surveyed area to determine the iodine content using the sulfate cerium catalytic spectrophotometric method and the hyposulphite quantitative titration method, respectively. The iodine level of each water sample was ranged from 0.611 to 1.473 μg/L. The median and the mean value of the iodine content in water were 0.972 and 0.979 ± 0.189 μg/L. The average iodine intake of each age group was higher that the recommended nutrient intakes (RNI) but lower than the tolerable upper intake level (UL). The median and the mean value of the iodine content in salt were 25.53 and 25.62 ± 1.70 mg/kg. Taken together, the present study investigated the iodine intake status of Wa school-aged children through examination of their dietary iodine intake, the environment, and the salt iodine status. Results showed that the status of the iodine uptake of the Wa children were higher than the RNI, but lower than the UL.