US County-level Structural Racism Effect Index and Cardiovascular Disease Mortality among Older Adults: A Bayesian Spatiotemporal Modeling

Background: Cardiovascular disease (CVD) remains the leading cause of mortality among older U.S. adults, yet the contribution of neighborhood-based structural racism remains inadequately quantified. This study quantifies the association between the Structural Racism Effect Index (SREI) and CVD mortality among adults aged {greater than or equal to}65 years, evaluating how this relationship varies across U.S. geographic regions to identify key areas for intervention. Methods: This ecological study applied a hierarchical Bayesian spatiotemporal framework to 2017-2020 Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiologic Research (WONDER) data to estimate the association between SREI and CVD mortality across 3,007 U.S. counties. SREI was modeled continuously and categorically, adjusting for sociodemographic covariates. Population attributable fractions (PAF) and attributable deaths (AD) quantified the potentially preventable burden and its spatial disparities. Results: From 2017 to 2020, approximately 2.79 million CVD deaths were observed, with significant spatial clustering (Moran's I = 0.35, p < 0.001). Each standard-deviation increase in SREI was associated with 13% higher CVD mortality (IRR: 1.13, 95% CrI: 1.12-1.15). A positive dose-response gradient was observed across SREI quartiles, with mortality 24% higher in the highest quartile than in the lowest (IRR: 1.24, 95% CrI: 1.20-1.28). The PAF was 6.94% (95% CrI: 6.13-7.73), corresponding to 193,472 potentially preventable deaths. High exceedance probabilities (>0.95) were concentrated in the Southeast, Appalachia, and the Midwest. Conclusions: Structural racism is a spatially patterned, dose-dependent predictor of older adult CVD mortality, underscoring the need for public health monitoring and neighborhood-based upstream interventions where disease burden is concentrated. Keywords: Structural Racism Effect Index; Neighborhood disadvantage; Cardiovascular Disease Mortality; Bayesian Spatiotemporal Analysis; Population Attributable Fraction; Health Disparities; Health Equity.