Lipoprotein(a) as an independent risk factor for coronary artery disease in patients below 40 years of age

Abstract

Coronary artery disease has assumed alarming proportions in Indians and often affects people at younger age. Traditional risk factors fail to explain the high incidence of disease. Although lipoprotein(a) has been shown to be a powerful risk factor for atherosclerosis, there is very limited data with regard to its significance in premature coronary artery disease. The present study was therefore undertaken to assess lipoprotein(a) levels and its role as a marker of coronary artery disease in patients below the age of 40 years. Lipid profile and lipoprotein(a) levels were estimated in 50 patients of angiographically proven coronary artery disease and an equal number of age-matched healthy controls. There was no significant difference in the family history of coronary artery disease, body mass index and waist-hip ratio between the two groups. Total plasma cholesterol, triglyceride and LDL-cholesterol levels were significantly higher and HDL-cholesterol significantly lower in patients as compared to controls. In patients of coronary artery disease, mean lipoprotein(a) levels, measured by ELISA method, were 35.0 +/- 32.4 mg/dL and the median was 26.7 mg/dL. These values were significantly higher than the mean of 20.3 +/- 17.0 mg/dL (p < 0.002) and the median of 13.8 mg/dL (p < 0.015) in controls. Multiple regression analysis, to assess the influence of various risk factors, showed that low HDL-cholesterol (odds ratio 4.62, 95% CI 1.84-11.60; p < 0.015) and elevated lipoprotein(a) levels (odds ratio 3.06, 95% CI 1.24-7.55; p < 0.001) were independent risk factors, whereas high total cholesterol and triglyceride levels did not have any independent influence on premature coronary artery disease. Our data thus suggest that lipoprotein (a) levels are elevated and constitute an independent risk factor in patients with premature coronary artery disease below 40 years of age.