Association of vitamin D deficiency with insulin resistance in middle-aged type 2 diabetics

Abstract

Background: Vitamin D deficiency contributes to the pathophysiology of insulin resistance (IR) and type 2 diabetes mellitus (T2DM). We investigated the association of 25-hydroxyvitamin D [25(OH)D] with IR and β-cell function in middle-aged participants.

Methods: We enrolled 90 controls and 90 T2DM patients of both genders aged 30-50 years. Serum 25(OH)D, fasting plasma insulin (FPI), fasting plasma glucose (FPG), HbA1c, and lipid profile were measured by standard methods. Insulin resistance and sensitivity were assessed by triglyceride glucose (TyG) index, homeostatic model assessment (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and β-cell function by HOMA-B.

Results: 25(OH)D deficiency was reported as 40% in control and 70% in T2DM patients. 25(OH)D concentration was positively associated with age, blood pressure, T2DM duration, FPG, HbA1c, TyG index, and HOMA-IR and negatively associated with HOMA-B and QUICKI among all the participants (p ≤.001). Participants with severe 25(OH)D deficiency (<10 ng/ml) were 39 times higher odds of being T2DM, while, those with moderate deficiency (10-19ng/ml) and insufficiency (20-29 ng/ml) were 16 times and 13 times higher odds of being T2DM, respectively.

Conclusion: Sufficient 25(OH)D concentration may lower the risk of development of IR and T2DM in middle-aged control and diabetic participants.

Keywords: Insulin resistance; Insulin sensitivity; Type 2 diabetes; Vitamin D; β-Cell function.