The Common Apolipoprotein A-1 Polymorphism -75A>G is Associated with Ethnic Differences in Recurrent Coronary Events after Recovery from an Acute Myocardial Infarction

Abstract

Since data regarding the relationship between a common polymorphism (SNP) of the apoA1 gene with apoA1 levels and risk of coronary artery disease are inconsistent, we hypothesized that its association with recurrent coronary events differs for White and Black individuals with diagnosed coronary heart disease. The apoA1 -75G>A SNP was genotyped in a cohort of 834 Black (n=129) and White (n=705) post-myocardial infarction patients. Recurrent coronary events (coronary-related death, non-fatal myocardial infarction, or unstable angina) were documented during an average follow-up of 28 months. Thirty percent of White and 21% of Black patients carried the SNP. Cox proportional-hazards regression analysis, adjusting for clinical and laboratory covariates, demonstrated that the SNP was not associated with recurrent events in the total cohort (HR=1.37, 95% CI 0.95–1.97; p=0.09) but was the only variable associated with an increased risk of recurrent cardiac events in Blacks (HR=2.40, 95% CI 1.07–5.40; p= 0.034). Conversely in Whites, the SNP was not associated with recurrent events (HR=1.12, 95% CI 0.75–1.67; p= 0.59) whereas apoB (HR=1.78, 95% CI 1.20 -2.65; p=0.0042) and calcium channel blocker use (HR=2.53, 95% CI 1.72–3.72; p<0.001) were associated; p=0.0024 for interaction between ethnicity and the SNP. A common apoA1 SNP is associated with a significantly increased risk of recurrent cardiac events among Black, but not White, post-myocardial infarction patients. Relationships with lipoproteins may help explain this finding.