Interplay between family History and polygenic risk for coronary heart disease: a cohort study among over 60 thousand individuals

Abstract Background The degree to which background genetic risk adds to self-report of family history of coronary heart disease (CHD) remains an important question. Methods We utilized data from the multiethnic Genetic Epidemiology Resource in Adult Health and Aging (GERA) cohort of 60,070 Kaiser Permanente of Northern California (KPNC) members (mean ± SD age=59 ± 9 years; 67% female; 18% non-white). We characterized the cohort at baseline in 2003-2007. Excluding those with missing self-report of family history of CHD (n=1,718) resulted in a final sample of 61,352. We stratified the cohort into not having (n=42,866; 70%) and having (n=18,486; 30%) self-reported family history of CHD and then (within stratum of family history of CHD) by three groups of CHD polygenic risk (low: quintile 1; intermediate: quintiles 2, 3 and 4 combined; and high: quintile 5) using a validated 12-SNP polygenic risk score (PRS) for CHD (CARDIO inCode-Score®). Incident CHD was based on ICD-9/10 codes for angina pectoris, myocardial infarction, revascularization procedures or CHD death (n=3,040) through 12/31/2022; mean follow-up was 14.5 years. Results Age-adjusted CHD incidence rates per 10,000 person years were estimated using Poisson regression (accounting for death and health plan disenrollment) by absence/presence of family history of CHD and polygenic risk groups. As shown in the Figure, polygenic risk provided additional risk stratification within categories of family history. The hazard ratio of high PRS (vs low PRS) adjusted for age, sex, 10 principal components of ancestry, smoking, body mass index, diabetes, hypertension, total cholesterol/HDL ratio and cholesterol lowering therapy was 1.62 (95% CI, 1.39-1.87; p<0.001) in those with no family history of CHD, and 1.66 (95% CI, 1.37-2.00; p<0.001) in those with family history of CHD (p-interaction PRS continuous*family history of CHD=0.93). Conclusions Our results show that polygenic risk predicts future CHD regardless of the presence of family history of CHD. Thus, it is not enough to rely of family history to fully characterize potential genetic burden. These data are therefore important for the future of precision medicine.