Inverse relationship between vitamin D status and insulin resistance and the risk of impaired fasting glucose in Korean children and adolescents: the Korean National Health and Nutrition Examination Survey ( KNHANES) 2009-2010

Objective: To investigate whether low vitamin D status was related to insulin resistance (IR) or impaired fasting glucose (IFG) in Korean adolescents, after adjusting for total body fat mass (FM). Design: A cross-sectional study. Setting: Korea National Health and Nutrition Examination Survey (KNAHNES) 2009-2010. Subjects: In total, 1466 participants (769 males) aged 10-19 years were assessed for serum 25-hydroxyvitamin D (25(OH) D) levels, for FM by whole-body dualenergy X-ray absorptiometry and for IR by homeostasis model assessment (HOMA-IR) after an 8 h fast. Results: Age-, sex-, season-and physical-activity-adjusted regression models showed that serum 25(OH) D levels were significantly related to markers of adiposity (P50? 016 for FM (g), P50? 023 for FM (%) and P50? 035 for fat mass index). When the participants were stratified into three 25(OH) D categories (, 37.5 nmol/l (n 553), 37.5 to,50 nmol/l (n 543) and $ 50 nmol/l (n 370)), significantly decreasing trends were observed for fasting insulin (all P<0.01), HOMA-IR (all P, 0? 001) and the odds ratios for IFG (all P for trend,0? 05) from the lowest to the highest 25(OH) D category, after adjustments for age, sex, physical activity and all markers of adiposity. In the multivariate logistic regression analysis, the likelihood of participants in the lowest serum 25(OH) D category having IFG was 2.96-3.15 compared with those in the highest 25(OH) D category (all P<0.05). Conclusions: There was a significant inverse relationship between vitamin D status and IR and the risk of IFG, independent of adiposity, in Korean adolescents.