Association between Serum 25-hydroxyvitamin D Levels and Type 2 Diabetes in Korean Adults

Previous studies have suggested that a vitamin D deficiency increases the risk of type 2 diabetes. This study evaluated the association between serum vitamin D levels and type 2 diabetes in Korean adults. This study included 9,014 subjects (3,600 males and 5,414 females) aged ≥50 years who participated in the Dong-gu Study. The subjects were divided into groups in whom the serum vitamin D level was severely deficient (<10 ng/mL), deficient (10 to <20 ng/mL), insufficient (20 to <30 ng/mL) and sufficient (≥30 ng/mL). Type 2 diabetes was defined by a fasting blood glucose level of ≥126 mg/dL and/or an HbA1c proportion of ≥6.5% and/or self-reported current use of diabetes medication. Multiple logistic regression was performed to evaluate the association between vitamin D status and type 2 diabetes. The age- and sex-adjusted prevalence of type 2 diabetes was 22.6%, 22.5% and 18.4% and 12.7% for severely deficient, deficient, insufficient, and sufficient, respectively. Multivariate modeling revealed that subjects with insufficient or sufficient vitamin D levels were at a lower risk of type 2 diabetes than were subjects with deficient vitamin D levels [odds ratio (OR), 0.82; 95% confidence interval (CI), 0.71-0.94 and OR, 0.51; 95% CI, 0.35-0.74, respectively]. Higher serum vitamin D levels were associated with a reduced risk of diabetes in Korean adults, suggesting that vitamin D may play a role in the pathogenesis of diabetes.