Association of Vitamin D Deficiency With Glycemic Control in Type 2 Diabetes Mellitus

Background Vitamin D is widely acknowledged for its important role in sugar metabolism by influencing inflammatory control, insulin production, and sensitivity. One of the main causes of problems in individuals with type 2 diabetes mellitus (T2DM) is inadequate glycemic management. This study aimed to evaluate the association between glycemic management and vitamin D levels in individuals with T2DM. Methods A total of 200 adult T2DM patients participated in this cross-sectional observational study at the endocrinology department in a tertiary care hospital as outpatients. The participants were divided into two subcategories based on blood glucose control: with a good HbA1c (<7%; n = 76) and with a poor HbA1c (≥7%; n = 124). To measure the levels of serum 25-hydrovitamin D (25(OH)D), a chemiluminescence immunoassay was utilized. 25(OH)D < 20 ng/mL was the indication for vitamin D insufficiency. BMI, gender, age, diabetes duration, and medication schedule were among the demographic and clinical data collected. The statistical analysis employed the chi-square test, the independent t-test, and the Pearson correlation. Statistical significance was defined at p-value <0.05. Results Vitamin D deficiency was present in 145 (72.5%) participants, and 101 (81.5%) individuals demonstrated poor glucose management compared to 44 (57.9%) participants in the good control group (p < 0.001). Patients with poorly controlled diabetes had substantially lower mean 25(OH)D levels (15.8 ± 5.9 ng/mL) than those with well-controlled diabetes (22.1 ± 6.3 ng/mL; p < 0.001). There was a negative correlation (r = -0.45; p < 0.001) between vitamin D levels and HbA1c. Conclusion In patients with T2DM, inadequate glycemic management is associated with vitamin D insufficiency. The findings suggest that, in the context of comprehensive diabetes care, monitoring and adjusting vitamin D levels are beneficial.