Relationship between vitamin D levels and glycaemic control in Type 2 diabetes mellitus patients in Lagos, Nigeria

Abstract

Background: Studies have reported a relationship between Vitamin D deficiency and type 2 diabetes mellitus (T2DM). There is no information on the Vitamin D status or relationship between Vitamin D and glycaemia in Nigerian patients with T2DM. The objective of this study was to determine the relationship between serum Vitamin D levels and glycaemic control, as determined by glycated haemoglobin (HbA1c) in adult patients with T2DM. Methods: This was a cross-sectional analytical study involving T2DM participants attending the Diabetes Clinic of the Lagos University Teaching Hospital. The study participants consisted of 114 T2DM and sixty healthy controls. Levels of serum Vitamin D, fasting glucose, insulin, HbA1c, calcium, albumin, phosphate, creatinine and alanine transaminase were determined. Insulin resistance and beta cell function were estimated with the homeostasis model assessment (HOMA-IR and HOMA-B, respectively). Statistical analysis was done using Statistical Package for Social Sciences, Version 20. Results: The mean age of the study participants was 52 ± 7.6 years for T2DM patients and 50 ± 8.4 years for controls. The female to male ratio in both T2DM and healthy controls was 3:2. The mean HbA1c was 7.3 ± 1.8%. Poor glycaemic control (HbA1c >6.5%) was present in 67 (58.8%) T2DM controls; forty-five (39.5%) subjects had both low Vitamin D levels and poor glycaemic control. There was a significant inverse correlation between serum Vitamin D concentration and HbA1c levels in T2DM patients (rs= −0.185; P