Evaluating the Role of Vitamin D3 in Modulating Insulin Resistance and Glycemic Control Among Type 2 Diabetic Nephropathy Patients Publisher



Aqeeli ONG ; Alkarawi INS ; Majidi Z ; Dashti N
Source: Acta Medica Iranica Published:2025

Abstract

Type 2 diabetes mellitus (T2DM) is a major global health concern, often complicated by diabetic nephropathy (DN), a leading cause of end-stage renal disease. Vitamin D3 has been implicated in various metabolic and inflammatory processes, potentially influencing insulin sensitivity and renal outcomes. However, the exact relationship between vitamin D3 levels, glycemic control, and insulin resistance in T2DM patients with different stages of DN remains unclear. This study aims to evaluate serum vitamin D3 levels in T2DM patients with varying degrees of albuminuria and to assess their correlation with markers of insulin resistance and glycemic control, compared with healthy controls. A case-control study was conducted involving 180 T2DM patients—divided into normoalbuminuria (n=60), microalbuminuria (n=60), and macroalbuminuria (n=60) groups—and 60 healthy controls. Glycemic Profile (Fasting blood glucose [FBS], HbA1c, fasting insulin), lipid profile (total cholesterol, triglycerides, LDL, HDL, VLDL), renal function markers (urea, creatinine, albumin-to-creatinine ratio [ACR], glomerular filtration rate [GFR]), calcium, and vitamin D3 levels were measured. Insulin resistance was assessed using the HOMA-IR index. Serum vitamin D3 levels were significantly lower in all T2DM subgroups than in controls (P<0.001), with the lowest levels observed in the macroalbuminuria group. A significant positive correlation was observed between vitamin D3 and FBS only in the microalbuminuria group (r= +0.437, P=0.016). No significant associations were found between vitamin D3 and HOMA-IR or other glycemic parameters across the groups. Markers of renal dysfunction, including serum creatinine, urea, and ACR, were significantly elevated with increasing severity of albuminuria. Vitamin D deficiency is prevalent in T2DM patients with nephropathy, especially those with advanced renal impairment. While no strong associations were found between vitamin D3 and insulin resistance, a positive correlation with FBS in early-stage nephropathy suggests a potential role for vitamin D in glycemic regulation during the progression of DN. Further longitudinal studies are warranted to explore the therapeutic implications of vitamin D supplementation in T2DM patients at risk of nephropathy. © 2025 Tehran University of Medical Sciences. All rights reserved.