Racialized economic segregation and breast cancer mortality among women in Maryland.

BACKGROUND Our objective was to determine the association between racialized economic segregation and the hazard of breast cancer (BC) mortality in Maryland. METHODS Among 35,066 women (24,540 White; 10,526 Black) diagnosed with incident invasive BC in Maryland during 2007-2017, exposure to racialized economic segregation was measured at the census tract level using Index of Concentration at the Extremes metrics. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards regression for the association between racialized economic segregation and the hazard of BC mortality, accounting for clustering at the census tract level. Models were adjusted for age and stratified by race, median age (<60 years, {greater than or equal to}60 years), and clinical characteristics. RESULTS Overall, the hazard of BC mortality was 1.84 times as high (95% CI: 1.64, 2.06) for the least privileged quintile of racialized economic segregation compared to the most privileged quintile. This association differed significantly (p-interaction< 0.05) by race and age, with 1.20 (95% CI: 0.90, 1.60) times the hazard of BC mortality for Black women versus 1.66 (95% CI: 1.41, 1.95) times the hazard for White women, and with greater hazards for younger women (HR: 2.17, 95% CI: 1.83, 2.57) than older women (HR: 1.62, 95% CI: 1.40, 1.88). CONCLUSIONS Our results suggest that BC survival disparities exist in Maryland among women residing in the least privileged census tracts with lower income households and higher proportions of Black residents. IMPACT Our findings provide new insights into the BC mortality disparities observed among women in Maryland.