Urinary iodine and sodium status of urban Korean subjects: a pilot study.

OBJECTIVES We estimated iodine status of Korean population by determining the concentration of spot urinary iodine (UI) with a reliable method based on the Sandell-Kolthoff reaction. MATERIALS AND METHODS A total of 540 urine samples from apparently healthy subjects were collected, and UI, urinary sodium (UNa), and urinary creatinine (UCr) were determined from those samples and analyzed with age. RESULTS There were significant decreases in either UI (P<0.0001), UI/UCr ratio (P=0.0001), UNa (P<0.0001), or UNa/Cr ratio (P=0.0001) in younger subjects than older ones. The median value of UI was 267.6 μg/L, but the median UI of the younger group (191.8 μg/L) was significantly decreased compared to that of the older group (383.9 μg/L). CONCLUSIONS This study showed that the median of UI in Korean urban population was in a more than adequate iodine nutritional state, but UI was significantly different between the younger age group and the older age group.