Leptin, hs-CRP and HOMA-IR in patients with type 2 diabetes: The role of different levels of vitamin D deficiency

Background: To evaluate the effects of different levels of vitamin D deficiency on blood glucose, leptin, and high sensitivity C-reactive protein (hs-CRP), insulin resistance and their associations.Methods: We quantified serum vitamin D level, hs-CRP, leptin, and fasting  blood  sugar (FBS)  levels in 25 type-2 diabetic patients with very low serum levels of 25-hydroxy vitamin D (deficient), ≤15 ng/ml; and 25 age, sex, and body mass index (BMI)-matched  type-2 diabetic patients with low serum levels of 25-hydroxy vitamin D (insufficient), 16 to 30 ng/ml. Homeostasis model assessment of insulin resistance (HOMA-IR) was  calculated  by  a  formula based  upon  values  of  FBS and insulin concentrations.Results: The mean value of vitamin D levels was 7.67±3.10 in vitamin D deficient group and 23.20±9.97 in vitamin D insufficient group. Patients with vitamin D deficiency had significantly higher FBS, postprandial glucose (PPG) and hemoglobin A1C (HbA1C) as compared to vitamin D insufficient group (p<0.01). We studied correlations of hs-CRP, HOMA-IR, and leptin in both vitamin D insufficient and deficient groups. There were significant positive correlations between leptin with hs-CRP (r = 0.58, p<0.01) and with HOMA-IR (r = 0.49, p<0.05) in vitamin D deficient group; Which these correlations remained significant after multiple adjustment for age, sex, BMI, systolic and diastolic blood pressure.Conclusion: In conclusion vitamin D deficient diabetic patients had elevated FBS, PPG and HbA1C compared with insufficient ones. The results also could possibly point the effect of vitamin D deficiency level on leptin associations with hs-CRP and insulin resistance.Keywords: Vitamin D deficiency, type 2 diabetes, leptin, C reactive protein, homeostasis model assessment of insulin resistance