The Association between Serum 25-Hydroxyvitamin D Concentrations and Depressive Symptoms in Korean Adults: Findings from the Fifth Korea National Health and Nutrition Examination Survey 2010

The aims of this study were to examine the association between circulating vitamin D (25(OH) D) levels and depressive symptoms and to evaluate the associations between depressive symptoms and various sociodemographic factors. Data on serum 25(OH) D levels, sociodemographic factors, and information on depressive symptoms were obtained from the Korea National Health and Nutrition Examination Survey V-1 2010. A total of 3,570 Koreans aged >= 20 years were included in the statistical analysis. Subjects with depressive symptoms had lower serum levels of 25(OH) D (41.6 +/- 16.2 nmol/L) than those without (44.3 +/- 16.2 nmol/L; P-value<0.05; effect size = 0.17). In a logistic regression analysis, the 25(OH) D sufficiency group (>= 50 nmol/L) revealed fewer depressive symptoms (OR, 0.72; 95% CI, 0.53-0.97; P-value = 0.032) after adjusting for multiple factors. In addition, females (OR, 3.61; 95% CI, 2.55-5.11; P-value, 0.001), problematic alcohol users (OR, 2.33; 95% CI, 1.63-3.34; P-value, 0.001), current smokers (OR, 1.43; 95% CI, 1.02-1.99; P-value = 0.036), and subjects who experienced weight loss (OR, 1.78; 95% CI, 1.30-2.44; P-value, 0.001) were more likely to answer "yes" on question for depressive symptoms. In conclusion, low serum levels of 25(OH) D were associated with an increased risk for depression symptoms in Korean adults. In addition, several sociodemographic factors were related to the depressive symptoms. Our results provide insight into the relationships among vitamin D status, sociodemographic factors, and depression in the Korean population.