INS and diabetes mellitus: A relationship between type 1 diabetes mellitus and vitamin D deficiency has been reported.5, 6 The prevalence of vitamin D deficiency in patients with type 1 diabetes was 15% to 90.6%.7–9 There is evidence that vitamin D is important in the prevention of islet cell death and might be useful in improving the survival of islet cell grafts, and it improves the production of insulin.