Journal of Invasive Cardiology

Abstract: 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.

J INVASIVE CARDIOL 2012;24(8):385-389

Key words: vitamin D deficiency, coronary artery disease

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Though vitamin D has been traditionally associated with bone health, adequate levels are also important for optimal cardiovascular (CV) function. The quest to identify new predictors of CV disease has focused the attention on vitamin D, given its association with various established risk factors for CAD, including hypertension, diabetes, obesity, metabolic syndrome, congestive heart failure, and prevalent coronary artery disease.^1,2 Vitamin D deficiency has also been linked to increased risk of adverse CV events including higher risk of myocardial infarction, CV death, and overall mortality.^3-5 However, other studies have reported absence of a significant correlation of vitamin D with CVD and the overall epidemiologic evidence is inconclusive, necessitating further studies to corroborate a potential link between the two.^6-9

Endothelial dysfunction is an important antecedent event in the development of CHD and atherosclerosis.^10,11 Vitamin D is known to affect vascular endothelium directly or indirectly through up-regulation of the renin-angiotensin system or via induction of smooth muscle proliferation and a pro-inflammatory state.^12-14 Hence, it is important to study the relationship between vitamin D deficiency and endothelial dysfunction assessed by brachial artery flow mediated vasodilatation, given their role in the development of CVD.