Vitamin D and diabetes in Koreans: Analyses based on the Fourth Korea National Health and Nutrition Examination Survey (KNHANES), 2008-2009

Abstract

Aims A causal relationship between vitaminD deficiency and the incidence of diabetes mellitus has been suggested, but little research has been conducted on the Korean population. Methods We analysed the glucose tolerance status and serum 25-hydroxyvitaminD concentrations in 12263 subjects >19years old who were registered for the Korea National Health and Nutrition Examination Survey, 2008-2009. Results Various demographic variables such as gender, age, season, resident area, physical activity, smoking, alcohol, marital status, education and occupation were associated with serum 25-hydroxyvitaminD concentrations. After adjusting for these variables as confounders, 25-hydroxyvitaminD concentrations in subjects with diabetes were significantly lower than those in subjects with normal glucose tolerance and those with impaired fasting glucose (P=0.005). Compared with the ≥75nmol/l subgroup of serum 25-hydroxyvitaminD concentration, the odds ratios and 95% confidence intervals fordiabetes mellitus were 1.206 (95%CI 0.948-1.534) in the 50- to 74-nmol/l subgroup, 1.339 (1.051-1.707) in the 25-to49-nmol/l subgroup and 1.759 (1.267-2.443) in the <25-nmol/l subgroup. Compared with the serum ≥75-nmol/l 25-hydroxyvitaminD subgroup, serum insulin and homeostasis model assessment2%B, a marker of insulin secretory capacity, were significantly higher, and homeostasis model assessment2%S, a marker of insulin sensitivity, was significantly lower in the <25- and 25- to 49-nmol/l serum 25-hydroxyvitaminD subgroups than those in the other subgroups (P<0.001). Conclusions The findings suggest that vitaminD deficiency, possibly involving altered insulin sensitivity, is associated with an increased risk for diabetes mellitus in the Korean population. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.