Excessive Iodine Status among School-Age Children in Korea: A First Report

Korea is considered an iodine sufficient country, and several studies have been conducted regarding iodine status in healthy Korean adults, pregnant women, and preschool children. However, data on iodine status in Korean school-age children are lacking. Therefore, the iodine nutrition status of Korean school-age children was investigated by measuring urine iodine concentration (UIC). This cross-sectional study conducted between April and September 2016 comprised 373 school-age children. UIC was determined using a modified microplate method employing ammonium persulfate digestion followed by Sandell-Kolthoff reaction. The median UIC was 458.2 μg/L. Excessive iodine intake (>300 μg/L) was found in 286 children (76.7%), with extremely high values exceeding 1,000 μg/L in 19.6% of subjects. Insufficient iodine intake (