Neighborhood Deprivation and Breast Cancer Mortality Among Black and White Women.

Importance: Neighborhood deprivation has been associated with increased breast cancer mortality among White women, but findings are inconsistent among Black women, who experience different neighborhood contexts. Accounting for interactions among neighborhood deprivation, race, and other neighborhood characteristics may enhance understanding of the association.
Objective: To investigate whether neighborhood deprivation is associated with breast cancer mortality among Black and White women and whether interactions with rurality, residential mobility, and racial composition, which are markers of access, social cohesion, and segregation, respectively, modify the association.
Design, Setting, and Participants: This population-based cohort study used Georgia Cancer Registry (GCR) data on women with breast cancer diagnosed in 2010 to 2017 and followed-up until December 31, 2022. Data were analyzed between January 2023 and October 2023. The study included non-Hispanic Black and White women with invasive early-stage (I-IIIA) breast cancer diagnosed between 2010 and 2017 and identified through the GCR.
Exposures: The Neighborhood Deprivation Index (NDI), assessed in quintiles, was derived through principal component analysis of 2011 to 2015 block group-level American Community Survey (ACS) data. Rurality, neighborhood residential mobility, and racial composition were measured using Georgia Public Health Department or ACS data.
Main Outcomes and Measures: The primary outcome was breast cancer-specific mortality identified by the GCR through linkage to the Georgia vital statistics registry and National Death Index. Cox proportional hazards regression was used to estimate age-adjusted and multivariable-adjusted hazard ratios (HRs) and 95% CIs for the association between neighborhood deprivation and breast cancer mortality.
Results: Among the 36 795 patients with breast cancer (mean [SD] age at diagnosis, 60.3 [13.1] years), 11 044 (30.0%) were non-Hispanic Black, and 25 751 (70.0%) were non-Hispanic White. During follow-up, 2942 breast cancer deaths occurred (1214 [41.3%] non-Hispanic Black women; 1728 [58.7%] non-Hispanic White women). NDI was associated with an increase in breast cancer mortality (quintile 5 vs 1, HR, 1.36; 95% CI, 1.19-1.55) in Cox proportional hazards models. The association was present only among non-Hispanic White women (quintile 5 vs 1, HR, 1.47; 95% CI, 1.21-1.79). Similar race-specific patterns were observed in jointly stratified analyses, such that NDI was associated with increased breast cancer mortality among non-Hispanic White women, but not non-Hispanic Black women, irrespective of the additional neighborhood characteristics considered.
Conclusions and Relevance: In this cohort study, neighborhood deprivation was associated with increased breast cancer mortality among non-Hispanic White women. Neighborhood racial composition, residential mobility, and rurality did not explain the lack of association among non-Hispanic Black women, suggesting that factors beyond those explored here may contribute to breast cancer mortality in this racial group.