Relation of Serum 25 Hydroxy Vitamin D3 Levels with Insulin Resistance in Type 2 Diabetic Patients and Normal Subjects

Abstract

Hypovitaminosis D is supposed to be associated with diabetes mellitus and metabolic syndrome. Defects in pancreatic I² cell function and/or insulin sensitivity are often present, to develop glucose intolerance or type 2 diabetes mellitus. There are accumulating evidence that vitamin D may influence these mechanisms. Aim of our study was to test the hypothesis of an association between hypovitaminosis D and insulin resistance in diabetic patients and normal subjects. We studied 101 type 2 diabetic patients and 60 controls. After detailed physical examination the venous blood was withdrawn, anthropometric measurements were taken, then an indirect measure of insulin resistance was calculated. Study population composed of diabetic and control groups. An indirect insulin resistance index was calculated and compared with other parameters including their 25 hydroxy vitamin D3 levels. In diabetic patients without insulin resistance; fasting blood glucose, fasting insulin and indirect insulin resistance index levels were significantly lower compared to diabetic patients with insulin resistance (p <0.05, <0.01 and <0.01 respectively). We also found that fasting insulin and indirect insulin resistance index levels of the control group without insulin resistance were significantly lower compared to controls with insulin resistance (p <0.001 both). We did not observe any difference in other parameters including vitamin D levels in all groups. These findings suggests that at least in Turkish population vitamin D levels are not associated with insulin resistance both in diabetics and normals.