A Trial to Study the Effect of Long Term Vitamin D Supplementation on Insulin Sensitivity

Type 2 diabetes is a major public health problem in India with an estimated a prevalence of approximately 4% and 12% in rural and urban areas respectively. Accumulating evidence suggests that serum cholecalciferol levels may be inversely related to the prevalence of diabetes, insulin resistance and metabolic syndrome. The trials available on the effect of Vitamin D supplementation on insulin/glucose metabolism have been conducted using small sample sizes in different subgroups document variable results (significant decrease in HbA1c concentration with insulin concentration in hemodialysis patients; insulin levels lower with oral Vitamin D in gestational diabetes; no effect of Vitamin D on serum insulin levels in post menopausal women). A double blind randomized controlled trial conducted at our institute using 3,60,000 IU of cholecalciferol over 6 weeks documented improvement in OGIS index of insulin sensitivity. We therefore, plan to study the long term effect of vitamin D supplementation on peripheral insulin sensitivity.