Association of Vitamin D Deficiency with Diabetic Nephropathy in Type 2 Diabetes: A Hospital-Based Cross-Sectional Study

This study shows a significant association between vitamin D deficiency and diabetic nephropathy, though its cross-sectional design precludes causal inference. Reverse causality and residual confounding cannot be excluded. Patients with DN had poorer glycemic control, dyslipidemia, and renal function, along with more frequent vitamin D deficiency. Routine vitamin D monitoring may support early detection and risk stratification in T2DM.