Background and methods: Vitamin D deficiency has been linked to an increased risk of coronary artery disease (CAD) and cardiovascular (CV) death. Endothelial dysfunction plays an important role in pathogenesis of CAD and vitamin D deficiency is postulated to promote endothelial dysfunction. Despite rising trends of CAD in Asians, only limited data are available on the relationship between vitamin D, CAD, and endothelial dysfunction.
Results: In a study of 100 patients undergoing coronary angiography, mean 25(OH)D level was 14.8 ± 9.1 ng/mL; vitamin D deficiency was present in 80% and only 7% had optimal 25(OH)D levels. Nearly one-third (36%) were severely deficient, with 25(OH)D levels <10 ng/mL. Those with vitamin D deficiency had significantly higher prevalence of double- or triple-vessel CAD (53% vs 38%), diffuse CAD (56% vs 34%), and higher number of coronary vessels involved as compared to those with higher 25(OH)D levels. Those with lower 25(OH)D levels had significantly lower brachial artery flow-mediated dilation (FMD; 4.57% vs 10.68%: P<.001) and significantly higher prevalence of impaired FMD (values <4.5%; 50.6% vs 7%; P<.002). A graded relationship between 25(OH)D levels and FMD was observed; impaired FMD was noted in 62.2%, 38.6%, and 13.3% in those with 25(OH)D levels <10 ng/mL, 10-20 ng/mL, and >20 ng/mL, respectively.
Conclusion: Indian patients with angiographically documented CAD frequently have vitamin D deficiency. Patients with lower 25(OH)D levels had higher prevalence of double- or triple-vessel CAD and diffuse CAD. Endothelial dysfunction as assessed by brachial artery FMD was also more frequently observed in those with low 25(OH)D levels.