Correlation of Serum Vitamin D Levels with Glycemic Control and Insulin Resistance in Type 2 Diabetes Mellitus

Abstract

Background: Vitamin D may influence glucose metabolism and insulin sensitivity; however, its association with glycemic control and insulin resistance in type 2 diabetes mellitus (T2DM) remains unclear.

Aim: To evaluate the correlation of serum vitamin D levels with glycemic control and insulin resistance in patients with T2DM.

Materials and Methods: This hospital-based, cross-sectional study included 120 patients with T2DM. Serum vitamin D, fasting blood glucose (FBG), postprandial blood glucose (PPBG), HbA1c, and fasting insulin were assessed. Insulin resistance was estimated using HOMA-IR. Correlation analysis was performed to evaluate associations between vitamin D and metabolic parameters.

Results: The mean age was 52.46 ± 10.28 years, with 55% males. Vitamin D deficiency was observed in 48.3% of patients. Mean vitamin D and HbA1c levels were 21.64 ± 9.28 ng/mL and 8.24 ± 1.46%, respectively. Patients with vitamin D deficiency had higher HbA1c (8.92 ± 1.42%) and HOMA-IR (8.12 ± 3.42) compared with vitamin D-sufficient patients (6.88 ± 0.82% and 3.32 ± 1.24, respectively). Serum vitamin D showed inverse correlations with HbA1c (r=−0.51) and HOMA-IR (r=−0.56).

Conclusion: Lower serum vitamin D concentrations were associated with poorer glycemic control and greater insulin resistance in the T2DM cohort.