Abstract WP193: Neighborhood-level Ethnic And Racial Segregation And Incident Stroke Risk

Background: Neighborhood-level ethnic and racial segregation has been linked to health status. We explored whether community level segregation is associated with incident stroke. Methods: We used data from Multi-Ethnic Study of Atherosclerosis (MESA). The exposure was neighborhood racial/ethnic segregation measured separately for self-identified White, Black and Hispanic participants and calculated as the Getis-Ord Gi* statistic based on the geocoded address of the participant. The Gi* statistic was categorized using the validated cut points of low, medium, and high neighborhood racial/ethnic segregation (high segregation means that the participant’s neighborhood primarily contained individuals of their race/ethnicity). The primary outcome was incident stroke (ischemic and hemorrhagic) during follow-up. We fit time-to-event Cox models with an interaction between race*segregation and adjustment for age, sex, hypertension, diabetes, hyperlipidemia, and current smoking. The results were further evaluated using marginal effects after logistic regression. Results: We included 5,411 MESA participants (mean age 62.0±10.1, 47.4% male, 44.4% White, 31.0% Black, 24.6% Hispanic), of which 111 (2.1%) had incident stroke during 8.0±1.3 years of follow-up. In the low, medium, and high neighborhood segregation categories there were 1,603 (29.6%), 1,667 (30.8%), and 2,141 (39.6%) individuals. High neighborhood segregation was more common in Black (45.7%) and Hispanic (39.7%) individuals than White (14.6%) (p<0.001). In Cox regression, the interaction between race and segregation was significant (p<0.1). Compared to low segregation, high segregation among White individuals was associated with 3.1% LOWER probability of incident stroke (p<0.001, from 3.4% to 0.3%), among Black individuals with 1.2% HIGHER probability of incident stroke (p=0.046, from 0.7% to 1.9%), and in Hispanic individuals there was an insignificant difference (p=0.842). Conclusions: For White individuals, a high level of segregation is associated with a lower probability of stroke, but for Black individuals with a higher probability of stroke. These findings call for further research into the mechanisms by which neighborhood segregation may mediate stroke risk.