Dietary intake, plasma levels of antioxidant vitamins, and oxidative stress in relation to coronary artery disease in elderly subjects

Abstract

The prevalence of coronary artery disease (CAD) in the urban population of India is similar to that in developed countries; Indian immigrants in industrialized countries have the highest prevalence of CAD. This is a cross-sectional survey within a random sample of a single urban setting in India. The relation between risk of CAD and plasma levels of vitamins A, C, E, and betacarotene was examined in 72 of 595 elderly subjects (12.1%) with CAD (aged 50 to 84 years). Plasma levels of vitamins A, C, E, and beta-carotene were significantly related to risk of CAD. Smoking (n = 145) and diabetes (n = 70) were the confounding factors. Lipid peroxides were higher in patients with CAD and diabetes, and in those who smoked. The inverse relation between CAD and low plasma vitamin C was substantially reduced after adjustment for smoking and diabetes. Vitamin A and E levels remained independently and inversely related to the risk of CAD after adjustment for age, smoking, diabetes, blood pressure, blood lipoproteins, and relative weight and body mass index. The adjusted odds ratios for CAD between the lowest and highest quintiles of vitamin E levels were 2.53 (95% confidence interval [CI] 1.11 to 5.31), vitamin C, 2.21 (95% CI 1.12 to 3.15), and beta-carotene, 1.72 (95% CI 0.88 to 3.62). The fatty acid composition of the diet, blood lipid levels, central obesity (waist-hip ratio),smoking habits, blood pressure, and plasma insulin levels do not appear to account for high rates of CAD among elderly Indians. The findings suggest that some elderly Indian populations with high rates of CAD can benefit from eating foods rich in antioxidant vitamins A, C, E, and beta-carotene. However, a reduction in vitamin levels may be due to changes in diet and lifestyle after diagnosis of CAD; therefore, more studies are necessary to confirm our findings.