Context: Vitamin D status in the Korean population has not been adequately determined.
Objective: To investigate the vitamin D status and the prevalence of vitamin D insufficiency in the Korean population, and also identify the predictors for vitamin D insufficiency in Korea.
Design and setting: The Fourth Korea National Health and Nutrition Examination Surveys (KNHANES IV) in the Korean population conducted in 2008.
Participants: 3,047 males and 3,878 females aged 10 years and older selected in all the 16 administrative districts of South Korea.
Main outcome measures: Serum 25-hydroxyvitamin D [25(OH)D] levels and the prevalence of vitamin D insufficiency defined as serum 25(OH)D level of less than 20 ng/ml.
Results: Vitamin D insufficiency was found in 47.3% of males and 64.5% of females, whereas only 13.2% of male and 6.7% of female population had a serum 25(OH)D level of greater than 30 ng/ml. Vitamin D insufficiency was most prevalent in the age of 20-29, with a rate of 65.0% in males and 79.9% in females, and least prevalent in the age of 60-69 in males and 50-59 in females. Those who work usually indoors were more predisposed to vitamin D insufficiency. In the adult population, predictors for vitamin D insufficiency included young age groups, spring and winter seasons, living in an urban area, and indoor occupations.
Conclusions: Vitamin D insufficiency is very common, and it is now a greater threat to the younger generation in Korea. Current recommendations for vitamin D intakes for Koreans are inadequate, especially for the youth.