Abstract 13386: The Association of High Polygenic Risk With Future Coronary Heart Disease Events Diminishes Later in Life

Introduction: Polygenic risk scores (PRS) for coronary heart disease (CHD) are associated with incident CHD events. We assessed whether the strength of this association differs over the life course. Methods: We studied 7,958 genotyped participants of European-ancestry without CHD enrolled in the Atherosclerosis Risk in Communities Study (ARIC). Participants were 45-64 years old at the baseline visit occurring 1987-89 with follow up available through 2015. A genome-wide PRS for CHD composed of 1.7 million variants was computed for each participant. Incident CHD was defined as clinically adjudicated myocardial infarction including silent infarction, coronary revascularization, or fatal coronary event. An extended Cox model was constructed with age as the model time scale. The association of PRS with incident CHD was assumed to be log-linear and further modeled as a function of age assuming differing piecewise constant effect sizes across the intervals ≤55, 55-65, 65-80, and ≥80 years. The regression model also included the following covariates: sex, systolic blood pressure, total and HDL cholesterol, history of diabetes, antihypertensive medication use, and smoking status. Results: In the ARIC cohort (median enrollment age 54, interquartile range [IQR] 49-59, female 52%), over a median of 24.5 years (IQR 14.4-28.1), there were 1,872 incident CHD events. In comparison to average polygenic risk for CHD (50th percentile of PRS distribution), harboring high polygenic risk (95th percentile) was associated with a 2.9-fold increased risk of incident CHD (95% CI 2.12-3.95) up to age 55 years, independent of conventional risk factors. The strength of association was attenuated later in life (Hazard ratio, age 55-65, 2.5 [2.14-2.84]; age 65-80, 1.87 [1.68-2.07]; age ≥80, 1.78 [1.38-2.31]) Conclusions: A genome-wide PRS for CHD is more strongly associated with incident coronary events at younger age. The strength of association declined later in life while remaining significant. The age-dependent association of PRS with CHD may need to be accounted for in risk prediction models.