Association of vitamin D deficiency with poor glycaemic control in diabetic patients

Objective: An association between serum levels of vitamin D and glycaemic control in type-2 diabetes mellitus (DM) patients has been reported in some of the studies carried out in the West. However, there are no reports on this relationship in Pakistani diabetic patients. The aim of this study was to ascertain whether vitamin D levels have any influence on glycaemic control in Pakistani patients with type-2 DM. Methods: In a cross-sectional survey, relationship between serum levels of 25-hydroxy vitamin D (25(OH)D) and glycated haemoglobin (HbA1C) was examined in 141 type-2 diabetic patients including 102 males and 39 females; age range 22 to 70 years, visiting the Aga Khan University Hospital during July 2013-April 2014. Venous blood was collected and analyzed for serum/plasma levels of 25(OH)D and related biomarkers using kit methods. HbA1C levels <7.0% and >7.0% were taken as indicators of good and poor glycaemic control, respectively. An association between 25(OH)D and HbA1C was investigated using regression analysis. Results: Percent vitamin D deficiency (serum level of 25(OH)D < 20 ng/ml) was significantly higher in patients with poor glycaemic control compared to patients with good glycaemic control (58.7% vs. 30.6%; p-value=0.006). Binary logistic regression analysis revealed positive association between vitamin D deficiency and poor glycaemic control while adjusting for BMI, serum levels of albumin, alanine aminotransferase and alkaline phosphatase (OR, 4.86 (95% CI, 1.9-11.9; p-value<0.001). Conclusion: The association between vitamin D deficiency and abnormal HbA1C in Pakistani diabetic patients is suggestive that patients with hypovitaminosis D could benefit from vitamin D supplementation.