25(OH)D status and demographic and lifestyle determinants of 25(OH)D among Korean adults.

Vitamin D deficiency is a global health problem that is associated with increased risks of major diseases. This study investigated the status of 25-hydroxyvitamin D [25(OH)D] and its demographic and lifestyle determinants among Korean adults. A total of 5,847 adults who had participated in the Korean National Health and Nutrition Examination Survey of 2008 (KNHANES) were included in the present study. Stepwise linear regression analysis was performed to determine the demographic and lifestyle determinants of 25(OH)D concentration. The weighted prevalence (standard error) of 25(OH)D deficiency (<20 ng/mL) was 49.9 (2.1)% among the males and 67.4 (1.7)% among the females. Severe 25(OH)D deficiencies (<10 ng/mL) were found in 5.7 (0.8)% of the males and 11.1 (1.0)% of the females. These peaked in spring and winter. Only 12.2 (1.1)% of the males and 6.4 (0.6)% of the females exhibited 25(OH)D sufficiency (>=30 ng/mL). The correlates with higher 25(OH)D concentration for both genders included summer, fall (vs spring), the 60s age group (vs 20s), rural residence (vs urban), moderate and vigorous physical activity (vs sedentary), alcohol consumption, and multivitamin supplementation. Higher education and unmarried status were inversely associated with 25(OH)D concentration for both genders. The strongest predictors of 25(OH)D concentration were season and residential area. 25(OH)D deficiency is a prevalent condition in Korea. Understanding the determinants of 25(OH)D can facilitate identification of persons at risk of 25(OH)D deficiency.