Prospective association of lipoprotein(a) concentrations and apo(a) size with coronary heart disease among men in the Multiple Risk Factor Intervention Trial

In this nested case-control study, lipoprotein (a) [Lp(a)] concentrations and apo(a) isoform size were measured in serum samples obtained from men participating in the prospective Multiple Risk Factor Intervention Trial (MRFIT). Serum from men aged 35 to 57 years and stored for up to 20 years were analyzed for Lp(a) levels (n=736) and isoform size (n=487), respectively. Cases involved nonfatal myocardial infarctions (MI; n=98), documented during the active phase of the study that ended on February 28, 1982 and coronary heart disease (CHD) deaths (n=148) monitored through 1990. Median Lp(a) levels did not differ between cases and controls and mean apo(a) size did not vary between cases and controls in the entire study population. When adjusted for age and Lp(a) concentration, logistic regression analysis indicated that small apo(a) isoforms were associated with CHD deaths among smokers (OR 3.31; 95% CI 1.07-10.28).