Examining racial segregation and underlying mechanisms related to VCID and incident stroke in the REGARDS study

Racial inequity in the development of neurological conditions as people age is a major public health issue. While many individual risk factors have been identified as predictors of both vascular contributions to cognitive impairment and dementia (VCID), as well as stroke, these individual factors do not fully explain the stark Black-

White disparities existing in these outcomes. Moreover, the structural mechanisms shaping these outcomes are far less understood; in particular, the racially unequal socio-environmental contexts that limit opportunities and resources based on race. Race-based school segregation and racial residential segregation (RRS) are

two, critical, structural racism and discrimination (SRD) factors of hypothesized importance in how SRD contributes to inequalities in VCID and stroke, yet few studies exist in this area. At the intersection of chronic disease, life course, and spatial epidemiology emerges a unique opportunity to address this critical gap. This

study leverages an ongoing, large-scale, population-based study: The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study. REGARDS is a national sample of over 30,000 adults (45-years and older) with oversamples of persons self-identifying as non-Hispanic Black and people living in the stroke belt.

The proposed study takes advantage of the longitudinal assessments of both VCID and stroke in this diverse cohort, and several other retrospective and prospective data related to biological, clinical (e.g., vascular health conditions), behavioral (e.g., health behaviors), socio-cultural (e.g., social support, social cohesion, perceived

discrimination, social networks), and built and social environment (BSE) factors across multiple levels of influence (individual, interpersonal, community, and societal) collected through the parent study and two ancillary studies. These data include state-based and school-level school segregation measures for each

school participants attended; objective, county-level educational quality measures for each year of schooling; historical participant residences that will be used to create a life course RRS exposure (median of 51-years) in the proposed study; and 9 BSE measures (food retail, parks, crime, commercial physical activity, healthcare,

neighborhood SES, places of worship, social engagement, and social service institutions) for over 40,000 geocoded locations in middle and older ages that will be expanded upon in the proposed study via additional locations and years of data. The proposed study aims to: 1) Determine the association between school

segregation on incident VCID and incident stroke later in life; the potential mediating role of educational quality; and to examine moderation by race, 2) Examine the association of RRS over the life course on incident VCID and incident stroke; and to examine moderation by race, and 3) Explore features of the residential

neighborhood and interpersonal factors that may mediate the link between RRS in middle and older ages and incident VCID and stroke; and to examine moderation by race. This state-of-the-art study will identify pathways through which SRD contributes to VCID and stroke, the protective resilience factors, and points of intervention.