Lipoprotein(a) and apolipoprotein(a) isoforms: no association with coronary artery calcification in the Dallas Heart Study.
BACKGROUND
Elevated plasma levels of lipoprotein(a) [Lp(a)] are an independent risk factor for cardiovascular disease in whites. Blacks have 2- to 3-fold higher plasma levels of Lp(a) than whites and yet do not have a correspondingly higher rate of coronary events. It remains unclear whether elevated plasma levels of Lp(a) are an independent risk factor for coronary atherosclerosis in individuals of African descent.


RESULTS
The relationship between plasma levels of Lp(a), apolipoprotein(a) isoform sizes, and the presence of coronary calcium was examined in 761 blacks and 527 whites (men aged >40 years, women aged >45 years) from a population-based sample. No relationship was found between plasma levels of Lp(a), apolipoprotein(a) isoform size, or a combination of these 2 variables and coronary artery calcium (CAC) in whites or blacks. No correlation was observed between plasma levels of Lp(a) and coronary calcium scores in any group, although all black men with very high plasma levels of Lp(a) (>300 micromol/L; n=7) were CAC-positive. Whites with high plasma levels of Lp(a) plus elevated plasma levels of LDL cholesterol (men) or reduced levels of HDL cholesterol (men and women) or who smoked (women) had a higher prevalence of CAC. In contrast, no joint effects between plasma levels of Lp(a) and other cardiovascular risk factors on coronary calcium were found in blacks.


CONCLUSIONS
No consistent independent relationship between plasma levels of Lp(a) or apolipoprotein(a) isoform size and coronary calcium was found in whites or blacks.
Guerra
Rudy
R
Donald W. Reynolds Center for Clinical Cardiovascular Research, Dallas, Tex, USA.
Yu
Zhaoxia
Z
Marcovina
Santica
S
Peshock
Ronald
R
Cohen
Jonathan C
JC
Hobbs
Helen H
HH
D000328:Adult; D001741:Black or African American; D001054:Apolipoproteins A / Q000097:blood*; D002114:Calcinosis / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D003324:Coronary Artery Disease / Q000097:blood / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D020033:Protein Isoforms; D014057:Tomography, X-Ray Computed; D044465:White People
D001054:Apolipoproteins A; D017270:Lipoprotein(a); D020033:Protein Isoforms