Association of LPA Variants With Aortic Stenosis

Abstract

Importance Elevated lipoprotein(a) levels are a risk factor for aortic stenosis (AS). However, a large-scale replication of associations between LPA variants and AS, their interactions with risk factors, and the effect of multiple risk alleles is not well established. Objective To replicate the association between LPA variants with AS and identify subgroups who are at higher risk of developing AS. Design, Setting, and Participants This case-control study of AS included 44 703 individuals (3469 cases) 55 years or older who were enrolled in the Genetic Epidemiology Research on Aging cohort and who were members of the Kaiser Permanente Northern California health care delivery system. The study leveraged the linkage of administrative health data, electronic medical records, genotypes, and self-reported questionnaire data. The 3469 AS cases were diagnosed between January 1996 and December 2015. Individuals with congenital heart disease were excluded. Exposures Two single-nucleotide polymorphisms in the LPA locus,rs10455872andrs3798220, that are known to associate with circulating plasma lipoprotein(a) levels and an LPA risk score. Main Outcomes and Measures Aortic stenosis or aortic valve replacement. Results The 44 703 participants were of European ancestry,of whom 22 019 (49.3%) were men. The mean (SD) age for the control group was 69.3 (8.3) years and the mean (SD) age for AS cases was 74.6 (8.5) years. Both LPA variants were associated with AS, with a per risk allele odds ratio of 1.34 (95% CI, 1.23-1.47; P = 1.7 × 10 −10) forrs10455872and 1.31 (95% CI, 1.09-1.58; P = 3.6 × 10 −3) forrs3798220after adjusting for age, age 2, and sex. The results remained significant after adjusting for risk factors. The estimates were similar for an LPA risk score. Individuals with 2 risk alleles had a 2-fold or greater odds of AS compared with individuals with no risk alleles (forrs10455872, homozygous odds ratio, 2.05; 95% CI, 1.37-3.07; P = 5.3 × 10 −4; forrs3798220, homozygous odds ratio, 3.74; 95% CI, 1.03-1.36; P = .05; and for compound heterygotes, odds ratio, 2.00; 95% CI, 1.17-3.44; P = .01). Forrs10455872, the odds ratio for AS was greatest in individuals aged 55 to 64 years and declined with age (interaction P = .03). Eachrs10455872risk allele was also associated with AS that was diagnosed 0.71 years earlier (95% CI, −1.42 to 0; P = .05). Conclusions and Relevance We provide a large-scale confirmation of the association between 2 LPA variants and AS, reaching genome-wide significance. In addition, individuals with 2 risk alleles have 2-fold or greater odds of developing AS. Age may modify these associations and identify subgroups who are at greater risk of developing AS.