Association of vitamin D concentrations with adiposity indices among preadolescent children in Korea

Abstract Background and Objective: We aimed to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) and anthropometric indicators of adiposity among Korean preadolescent children aged 7–9 years. Subjects and Methods: Children aged 7 to 9 from the Ewha Birth & Growth Cohort were followed up from July to August 2011. Serum 25(OH)D concentration was measured using radio immunoassay. We assessed the magnitude of cross-sectional association with vitamin D concentrations and indicators of adiposity [body mass index (BMI), waist circumference (WC), mid-arm circumference (MAC), body fat mass (BFM), percent body fat (PBF), and triceps skinfold thickness (TSF)] using multiple linear and logistic regression analyses adjusted for sex, age, birth order, maternal education, and fruit/fruit juice intake. Results: Thirty-two (16%) out of a total of 205 children showed an optimal level of serum 25(OH)D, but most children did not reach a sufficient level (<30 ng/mL) even in summer. The level of 25(OH)D was inversely associated with BMI (β=–0.10, p<0.01), WC (β=–0.28, p<0.01), and BFM (β=–0.12, p=0.02) after adjusting for confounding factors and showed marginal boundary with PBF (β=–0.20, p=0.06) and TSF (β=–0.11, p=0.08). Regarding the risk of overweight, a 13% protective effect per 1 ng/mL increase of 25(OH)D was shown even after adjusting for relevant confounding factors (adjusted odds ratio=0.87, 95% confidence interval 0.78–0.98). Conclusions: We found that the 25(OH)D concentrations were inversely associated with adiposity indices in preadolescent children. This study suggests that adequate vitamin D intake in growing children is crucial to maintain an optimal vitamin D level to prevent obesity and obesity-related health problems later in life.