No association between plasma lipoprotein(a) concentrations and the presence or absence of coronary atherosclerosis in African-Americans

Elevated plasma concentrations of lipoprotein(a) [Lp(a)] are associated with coronary atherosclerosis in Caucasians. Although African-Americans have a higher median plasma Lp(a) concentration than Caucasians, they do not have a greater incidence of coronary atherosclerosis. This study was performed to determine whether the plasma concentration of Lp(a) is associated with coronary atherosclerosis in African-Americans. The fasting plasma concentrations of Lp(a) and lipoproteins were measured in 140 African- American subjects (6 men, 78 women, aged 31 to 80 years) 18±16 months (mean±SD) after they underwent coronary angiography: 72 had angiographically normal coronary arteries and 68 had >70% luminal diameter narrowing of one or more major epicardial coronary arteries. The groups were similar in age, sex, and other risks factors for atherosclerosis. The subjects with coronary artery disease had higher plasma concentrations of total cholesterol, triglycerides, and VLDL and LDL cholesterol (P=.04) and lower concentrations of HDL cholesterol (P-.0001) than subjects without coronary artery disease, but there was no significant difference in the plasma concentration of Lp(a). The distribution of apolipoprotein(a) alleles by size was also not significantly different between the two groups. These results suggest that the plasma concentration of Lp(a) is not an independent risk factor for coronary artery disease in African-Americans.