Does Vitamin D Level Affect Beta Cell Activity?

Abstract

Objective: The prevalence of vitamin D deficiency is ever-increasing throughout the world. Vitamin D deficiency is associated with disorders such as diabetes, insulin resistance, obesity, dyslipidemia, and hypertension. This research study was carried out to assess serum vitamin D levels of patients with type 2 diabetes, insulin resistance, obesity, and impaired fasting glucose. Method: This study was carried out on 504 patients, who were newly diagnosed and did not receive medication before, aged 18 to 80 years, and who had type 2 diabetes, insulin resistance, obesity, and impaired fasting glucose. Their fasting glucose, fasting insulin, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoproteincholesterol, triglyceride, 25(OH)D concentration, height and body weight measurements were analyzed retrospectively. Body mass index, homeostatic model assessment (HOMA) for insulin resistance and HOMA beta (B) values of the patients were calculated. Results: It was found that 89.9% of the patients with type 2 diabetes, 90.6% of the insulin resistance patients, 91.7% of the obesity patients and 94.1% of the impaired fast glucose patients had less than 30 ng/ mL of serum 25(OH)D concentration. It was seen that the serum 25(OH) D concentrations of the patients were negatively correlated with their fasting insulin concentrations and HOMA B values, and positively correlated with their HDL-cholesterol levels. Conclusion: Based on this study, vitamin D deficiency was found to be common in the patients with type 2 diabetes, insulin resistance, obesity, and impaired fasting glucose. Serum 25(OH)D concentrations were correlated with the levels of fasting insulin, HDL-cholesterol, and betacell function. Keywords: HOMA B, HOMA-IR, insulin resistance, obesity, type 2 diabetes, vitamin D