Incidence and Risk Factors for Aortic Dissection in a Community-Based Cohorts: The Atherosclerosis Risk in Communities (ARIC) and Multi-Ethnic Study of Atherosclerosis (MESA) Studies

Despite its high mortality, prospective, population-based data on incidence and risk factors of aortic dissection (AD) remain limited. We followed 22,171 adults (mean age 56.6 years; 54.0% female) without baseline aortic disease from pooled ARIC and MESA cohorts for 20.2 years. Incident AD (n=97) was adjudicated using ICD codes. Cox regression examined associations between age, sex, smoking, diabetes, and hypertension and AD risk. SBP and DBP defined blood pressure levels were assessed in separate models. A four-variable points score (age, sex, SBP category, smoking) was developed and optimized using Youden's index to identify a binary risk threshold. AD incidence was 21.8 per 100,000 person-years, higher in older adults, hypertensives, and current smokers. Independent predictors included age (HR:2.13 per decade, 95%CI:1.57-2.88), male sex (HR:1.67,1.08-2.53), hypertension (HR:2.60,1.42-4.77), and current smoking (HR:4.26 for 1-9 pack-years; HR6.11 for ≥10). Diabetes was associated with nominally lower risk (HR:0.25, 0.06-1.01; P=0.052). Elevated SBP (120-129mmHg: HR:2.51; ≥140mmHg HR 4.21) and DBP (80-89mmHg: HR:2.19; ≥90mmHg: HR:2.77) were associated with higher risk. The predictive score showed good discrimination (C=0.78) with 10- and 20-year cumulative incidence ranging from 0-0.43% and 0.07-1.23%, respectively. A Youden-optimized threshold of ≥10 points classified participants into high and low risk groups, with the high-risk group demonstrating seven-fold higher AD hazard (HR 6.99, 4.61-10.61). In this multi-cohort prospective study, increasing age, male sex, elevated blood pressure, and current smoking were associated with higher AD risk. An exploratory four-variable score discriminated well, and a binary threshold effectively identified high-risk individuals.