Association of Residential Segregation with Mortality in the U.S., 2018-2022.

Introduction: This study aimed to examine the association of county-level racial and economic residential segregation with mortality rates in the U.S. between 2018 and 2022.

Methods: Residential segregation was measured by the Index of Concentration at Extremes and categorized into quintiles. Outcomes included 2018-2022 county-level age-adjusted mortality rates from all causes and the top 10 causes. Multi-level linear mixed modeling was clustered at the state level and adjusted for county's poverty, metropolitan status, and racial composition.

Results: A total of 3,129 counties were included. County-level age-adjusted mortality rates decreased as the segregation level decreased for all causes (from 1078.8 deaths in the most segregated counties to 734.92 deaths in the least segregated counties per 100,000 persons per year) and for 10 leading causes. Adjusted rate ratios showed dose-response associations between segregation and mortality from all-causes and 9 out 10 leading causes. Using the least segregated counties as the reference group, the adjusted rate ratios (aRR) for all-cause mortality was 1.25 (95% confidence interval: 1.22, 1.28), 1.20 (1.17, 1.22), 1.13 (1.11, 1.15), and 1.09 (1.08, 1.10) for the first (most segregated) through the fourth quintile of segregation, respectively.

Conclusions: Racial and economic residential segregation was positively associated with mortality rates at the county level in the contemporary U.S. Future study should elucidate the mechanisms underlying associations to inform evidence-based interventions and improve the health of the entire population.