No Association Between Plasma Lipoprotein(a) Concentrations and the Presence or Absence of Coronary Atherosclerosis in African-Americans

Abstract

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 (62 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 risk 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.

High Levels of Lp(a) With a Small Apo(a) Isoform Are Associated With Coronary Artery Disease in African American and White Men

“…Our results are consistent with previous studies demonstrating that in African Americans, neither the elevation of Lp(a) levels nor the presence of small apo(a) isoforms alone was significantly associated with CAD. 15,30 However, our demonstration that the combination of elevated Lp(a) levels and small apo(a) size was associated with CAD in African American and white men provides the first experimental evidence supporting previous suggestions that ethnic differences in the relationship between apo(a) isoform size and Lp(a) levels may have an impact on the use of Lp(a) level as a risk factor. 20,25 Thus, an elevated Lp(a) level is a poor surrogate marker for the relevant risk factor, ie, high levels of small-isoform Lp(a), in African Americans, but the strong association in whites between elevated Lp(a) and small apo(a) size makes elevated Lp(a) levels a reasonable surrogate marker in this group for elevated small-isoform Lp(a).…”

“…We suggest that the failure to observe an association between Lp(a) and CAD in African Americans in other studies 15,30 reflects analysis of the relationship between either Lp(a) levels or apo(a) size with CAD, without taking into consideration the level of Lp(a) associated with different apo(a) isoforms. The possibility that size variation of apo(a) could be associated with cardiovascular disease has been raised in previous studies, although the results have been inconsistent.…”

“…26 Elevated Lp(a) levels were defined as Ն30 mg/dL (Ն72 nmol/L). [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][17][18][19][20][21][22][23][24] …”

LP(a) phenotypes and levels in angiographically proven coronary heart disease patients and controls

“…The association between high plasma concentrations of Lp(a) and CAD is in agreement with findings in some nested case-control studies (12,16) and two recent prospective studies (18)(19)(20)(21), whereas other studies with similar design did not support such an association (14).…”

“…Increased plasma Lp(a) level was reported not to be linked to cardiovascular diseases in all ethnic groups; in the African-Americans Lp(a) was not an independent risk factor for coronary artery disease (CAD) (14).…”