Iodine status in Korean preschool children as determined by urinary iodine excretion

Iodine is a trace element of thyroid hormones. Excessive or insufficient iodine intake is associated with various thyroid diseases. Urinary iodine (UI) is a sensitive indicator and a recommended barometer of population iodine intake. In Korea, there has been no available data regarding iodine intake in preschool children. We investigated the iodine intake status of Korean preschool children through examination of their UI.

This cross-sectional study was performed in 611 healthy preschool children (302 from Seoul and 309 from Masan), aged from 2 to 7 in 2010. UI concentration was measured by inductively coupled plasma-mass spectrometry.

The median UI concentration was 438.8 μg/L. Insufficient iodine intakes (<100 μg/L) were seen in 24 children (3.9%), and excessive iodine ingestion (>300 μg/L) was found in 406 children (66.4%). There were no significant differences in UI between different sexes and ages. Additionally, the median UI concentration was higher in children from Seoul (512.2 μg/L) than that in children from Masan (362.4 μg/L, P < 0.001).

About two-thirds of Korean preschool children were in the state of excessive iodine intake, and 3.9% of children showed insufficient iodine intake. Preventive measures and follow-up for iodine intake in preschool children are needed.