Association Between Hypovitaminosis D and Angiographic Severity of Coronary Artery Disease in Bangladesh.

Background Coronary artery disease (CAD) remains a major cause of morbidity and mortality worldwide. Vitamin D deficiency has been increasingly linked to the pathophysiology of atherosclerosis; however, its association with the severity of CAD remains inconclusive, particularly in Bangladeshi populations where hypovitaminosis D is highly prevalent. The primary objective of this study was to compare serum vitamin D status between patients with angiographically confirmed CAD and those without CAD. The secondary objective was to evaluate the association between serum vitamin D levels and the angiographic severity of CAD and to explore the ability of vitamin D to discriminate multivessel from single-vessel disease among patients with angiographically confirmed CAD. Materials and methods This hospital-based cross-sectional comparative study was conducted among 300 adults undergoing coronary angiography at Bangladesh Medical University and Dhaka National Medical Institute Hospital from January to December 2024. Eligible participants were screened consecutively and enrolled within predefined angiographic strata until 150 participants with angiographically confirmed CAD and 150 participants without angiographic evidence of CAD had been included. Sociodemographic, clinical, anthropometric, biochemical, and angiographic variables were assessed contemporaneously and systematically recorded using a structured case record form. Serum vitamin D, fasting lipid profile, HbA1c, calcium, alkaline phosphatase, and parathyroid hormone levels were measured using standard laboratory methods. Among participants with CAD, angiographic severity was assessed according to the extent of coronary vessel involvement. Results Mean serum vitamin D levels were significantly lower among participants with CAD than among those without CAD (18.78 ± 6.66 ng/mL vs. 29.25 ± 3.84 ng/mL; p < 0.001). Triple-vessel disease was the most frequent angiographic pattern, observed in 68 (45.3%) patients with CAD. Serum vitamin D levels showed a significant inverse correlation with the extent of coronary vessel involvement (rₛ = -0.262, p = 0.001), indicating that lower vitamin D levels were associated with greater angiographic severity. Exploratory ROC analysis identified a serum vitamin D threshold of ≤21.54 ng/mL for discriminating multivessel from single-vessel CAD, with an area under the curve of 0.619 (95% CI: 0.513-0.725; p = 0.025), sensitivity of 72.5%, specificity of 53.7%, and overall accuracy of 67.3%, indicating limited discriminative ability. In multivariable logistic regression analysis, age <50 years (AOR = 3.614, 95% CI: 1.380-9.467; p = 0.009) and serum vitamin D ≤21.54 ng/mL (AOR = 2.669, 95% CI: 1.241-5.741; p = 0.012) were independently associated with multivessel CAD within the study population. Conclusions Hypovitaminosis D was significantly associated with greater angiographic severity and multivessel involvement among patients with CAD. Although a serum vitamin D threshold of ≤21.54 ng/mL demonstrated limited discriminatory performance for multivessel CAD, lower vitamin D levels remained independently associated with more extensive coronary involvement after multivariable adjustment. These findings support a potential role for serum vitamin D as an adjunctive marker of CAD severity, although its clinical utility requires further validation in larger prospective studies.