Low vitamin D levels are associated with atopic dermatitis, but not allergic rhinitis, asthma, or IgE sensitization, in the adult Korean population

Background: The effect of vitamin D on allergic conditions is unclear. In particular, large-scale, population-based studies examining this relationship in adult Asian populations are lacking. Objective: To evaluate the association between serum vitamin D levels and allergic conditions in the general adult Korean population. Methods: A cross-sectional study was performed by using data collected from 15,212 individuals 19 years or older who participated in the Korean National Health and Nutrition Examination Survey from 2008 to 2010. The confounder-adjusted mean serum 25-hydroxyvitamin D (25[OH]D) levels of participants with and without allergic conditions (including atopic dermatitis, asthma, allergic rhinitis, and increased total and allergen-specific serum IgE) were compared by using multiple linear regression analyses. Multiple logistic regression analyses with confounder adjustment estimated the odds ratios (ORs) for developing each condition according to adequate, inadequate, or deficient serum 25(OH)D levels. Results: After adjusting for potential confounders, mean serum 25(OH)D levels were significantly lower in participants diagnosed with atopic dermatitis than in those without this diagnosis (mean +/- SE, 18.58 +/- 0.29 ng/mL vs 19.20 +/- 0.15 ng/mL; P = .02). Compared with participants with adequate vitamin D levels (>= 20 ng/mL), confounder-adjusted ORs of atopic dermatitis were significantly higher in those with inadequate (12-19.99 ng/mL) or deficient (<12 ng/mL) levels (OR [95% CI], 1.50 [1.10-2.06] and 1.48 [1.04-2.12], respectively; P = .02). This relationship was not observed in participants with the other allergic conditions. Conclusion: Vitamin D-insufficient adult individuals within the general Korean population have an increased likelihood of atopic dermatitis, but not asthma, allergic rhinitis, or IgE sensitization.