Determinants of Vitamin D deficiency among type 2 diabetes mellitus patients: A retrospective study

Recent studies have shown an association between vitamin D deficiency (VDD) and type 2 diabetes mellitus patients (T2DM), but the precise relationship between these conditions has yet to be clarified. In this study, we aimed to estimate the incidence of VDD among diabetic patients and identify any relationship between diabetes and the determinants of VDD among T2DM individuals. A retrospective cross-sectional study was conducted at King Abdulaziz University Hospital, Jeddah, Saudi Arabia. Patients of either gender were selected from electronic records and checked for vitamin D levels, glycosylated hemoglobin (HbA1c), and other parameters. A total of 864 subjects were enrolled. Subjects were grouped according to HbA1c levels, with < 5.7%, 5.7% to 6.49%, and > 6.5% considered normal, impaired, and diabetic, respectively. VDD was common, with an incidence of 723 (83.7%) subjects. A significantly lower vitamin D level was found in diabetic subjects than in nondiabetic subjects (29.1 ± 12.0 vs 44.0 ± 28.3, P < .001). A total of 207/209 (99%) subjects with impaired HbA1c and 179/183 (97.8%) people with diabetes had VDD. Interestingly, none of the diabetic or impaired HbA1c subjects had normal vitamin D levels. A significant association was found between VDD and being > 50 years old, overweight, or obese, as well as HbA1c, fasting plasma glucose, calcium, and total cholesterol (TC) levels. A high rate of VDD and significantly lower vitamin D levels were found in diabetic subjects. Age, being overweight, obesity, HbA1c, and fasting plasma glucose were the few determinants of VDD among T2DM patients. These findings highlight the importance of addressing vitamin D status in managing and preventing T2DM, particularly in those over the age of 50, those who have higher body weight, and those with raised HbA1c and fasting plasma glucose levels.