The association between hypovitaminosis D and pediatric allergic diseases: A Korean nationwide population-based study

Background: There is stilt considerable disagreement regarding the rote of vitamin D or exacerbation of allergic diseases. Objective: To investigate the association between serum vitamin D levels and eel of allergic diseases in elementary schoolchildren. Methods: A nationwide cross-sectional survey was conducted in children ages 6-7 years from 45 randomly selected elementary schools. The presence of atopic dermatitis (AD) or asthma was defined an medical treatment of children for AD or asthma within 12 months of the survey. The presence of allergic rhinitis (AR) was defined as medical treatment fir AR during the past 12 months and a positive skin test response. Current AD was defined as col-firmed eczema on physical examination. Serum 25-hydroxyvitamin D (25[OH]D) was measured by chemiluminescent immunoassay. Results: Questionnaire data and blood samples were collected from 3720 children. The overall prevalence rates of vitamin D insufficiency (20-29 ng/mL) and deficiency (<20 ng/mL) were 64.0% and 18.4%, respectively. For a 1 ng/mL decrease in 25(OH)D, the adjusted odds ratio (aOR) for AR was 1.020 (95% confidence interval [CI], 1.002-1.040) and the aOR for current AD was 1.027 (95% CI, 1.006-1.047). For each 1 ng/mL decrease in 25(OH)D, the aOR for positive skin-prick test reactivity was 1.013 (95% CI, 1.000-1.027). No significant association between vitamin D level and the prevalence of asthma was observed. Conclusions: A high prevalence and low vitamin D levels were also D deficiency and insufficiency was found in Korean elementary schoolchildren, with recent symptoms of AD and AR.