Abstract 9398: Associations Between Blood Pressure, Race/Ethnicity, and Incident Stroke Type: A Pooled Cohort Analysis of ARIC, CARDIA, CHS, MESA, FOS, NOMAS

Introduction: Stroke risk varies by systolic blood pressure (SBP) and race/ethnicity. Whether the relationship between cumulative mean SBP and first-time incident stroke type differs by racial/ethnic group is unknown. This study examines the relationship between cumulative mean SBP and first-time incident stroke among 3 major stroke types: ischemic stroke (IS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH) and how race/ethnicity influences these relationships, using a pooled cohort analysis. Hypothesis: We hypothesize that race/ethnicity modifies the association between cumulative mean SBP and incident stroke type. Methods: Data were pooled from 38,325 participants with baseline age ≥18 and ≥1 SBP measurement before the first incident stroke from 6 US longitudinal cohorts from 1971 to 2019: Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Cardiovascular Health Study, Framingham Offspring Study, Multi-Ethnic Study of Atherosclerosis, and Northern Manhattan Study. A multivariable-adjusted Cox proportional hazard model was used to estimate the association between cumulative mean SBP, race/ethnicity, and time to incident stroke (overall, stroke type, and race/ethnicity*stroke type). Results: Median follow-up was 22.3 years. Mean (SD) baseline age was 53.2 (17.1) years, with 54.5% female, 24.9% Black, and 8.8% Hispanic. Baseline mean (SD) SBP was 136.8 (20.5) mmHg. Race/ethnicity modified the association of SBP with time to ICH (P-interaction=0.006) but no other stroke types. Compared to White participants, the association between higher SBP on ICH risk was greater in Black participants but not different in Hispanic participants (Table). A 10-mmHg higher SBP was associated with a higher risk of ICH than IS (Table). Conclusions: We found that race modifies the association between SBP and ICH risk, such that ICH risk is 19% higher per 10-mmHg for Black individuals than White individuals.