The Effect of Treating Vitamin D Deficiency or Insufficiency on Serum Adiponectin, Leptin and Insulin Resistance of Type 2 Diabetes Mellitus Patients: A Pilot Study

Vitamin D deficiency is considered as one of the most prevalent healthcare problems in the world. Vitamin D contributes to insulin synthesis and secretion. Deficiency of vitamin D leads to insulin resistance which is the major cause of type 2 diabetes mellitus. We aim to evaluate the effect of treating vitamin D deficiency or insufficiency on serum adiponectin, leptin, and leptin to adiponectin ratio (LAR) of type 2 diabetes mellitus patients. Forty patients with type 2 diabetes mellitus were included according to the inclusion criteria of the study. Fasting venous blood samples were obtained and evaluated before and after the treatment of vitamin D deficiency or insufficiency. Then, blood levels of leptin, adiponectin, and LAR (an indicator of insulin resistance) were measured. The results of study indicate a significant decline in circulating leptin and adiponectin after vitamin D treatment, but it doesn’t cause a noteworthy change in LAR. Furthermore, the study demonstrates that female gender, higher body mass index, and triglyceride levels increase LAR significantly. It was concluded that the treatment of vitamin D deficiency or insufficiency doesn’t change insulin resistance in diabetic patients. Moreover, we concluded that LAR is not a reliable method to compare insulin resistance between men and women due to sex-related differences in adipose tissue.