Lipoprotein(a) and acute myocardial infarction: Differential risk across age and sex subgroups

ObjectiveLipoprotein(a) is an identified risk factor for acute myocardial infarction; however, its role in specific subgroups is inconclusive. This case-control study examined whether classical risk factors modify the association between lipoprotein(a) levels and acute myocardial infarction across subgroups.MethodsOur study involved 2946 patients with initial acute myocardial infarction and 14,571 controls. Data were processed using multiple imputation and propensity score-based matching. Binary logistic regression, stratification, and sensitivity analyses were performed to explore associations.ResultsThe acute myocardial infarction group had a significantly greater proportion of men, smokers, and alcohol consumers as well as higher lipoprotein(a) levels. After risk factor adjustment in Model 2, the odds ratios and 95% confidence intervals for lipoprotein(a) (Quartile 2-Quartile 4) were 1.11 (0.97, 1.28), 1.24 (1.07, 1.42), and 1.45 (1.26, 1.66), respectively. In older patients, the adjusted odds ratio for acute myocardial infarction in Quartile 4 (vs. Quartile 1) was 2.15 (1.76-2.63)-higher than that in younger patients. Among female participants, the odds ratio for Quartile 4 was 2.61 (1.98-3.45), exceeding that in men. Compared with the younger/male group, the older/female group exhibited escalating acute myocardial infarction risks (adjusted odds ratios: Quartile 2 = 1.48 (1.00-2.18); Quartile 3 = 1.97 (1.38-2.81); and Quartile 4 = 2.88 (2.04-4.05)), culminating in a 2.88-fold elevation in Quartile 4. Repeat analyses of the complete dataset yielded the same results.ConclusionsHigh lipoprotein(a) levels independently increased the risk of initial acute myocardial infarction in older women, suggesting its role as a lipid-lowering therapy target in this population.