Could equalizing neighborhood socioeconomic status and greenness reduce racial disparities in all-cause mortality among men with prostate cancer?

Abstract

BackgroundNeighborhood contextual factors are associated with racial disparities among men with prostate cancer (CaP), but studies often separately emphasize socioeconomic status or built environment. We estimated the reduction in mortality disparities following a hypothetical joint intervention to equalize both neighborhood socioeconomic status and greenness across Black and White men with CaP. MethodsBlack and White men diagnosed with CaP from January 2000 to December 2015 were followed for up to 10 years using data from the Pennsylvania and Massachusetts Cancer Registries. Racial disparity was defined as the 10-year all-cause mortality risk difference between Black compared to White men, standardized to age, race, diagnosis year, state, and population density. The racial disparity was estimated using Cox models with 95% confidence intervals obtained using bootstrapping. Neighborhood contextual risk factors included socioeconomic characteristics (census block group income, poverty, racialized economic spatial polarization, educational attainment, home value) and greenness within 250m of residential address. We modeled the impact of modifying neighborhood contextual risk factors by z-scaling neighborhood characteristics to 0.5 standard deviation above or below the mean. This resulted in setting neighborhood poverty=3%, income=$56,000, home value=$164,000, 7% with high school diploma or lower, spatial polarization=0.10, and NDVI=0.60. ResultsThe cohort included 169,195 men (10% Black), with 38,672 deaths over 1,219,552 person-years of follow-up. There were 41.6 (95% CI: 35.6, 47.6) excess deaths per 1,000 over 10 years among Black men. The disparity was attenuated under the hypothetical intervention (17.1 deaths per 1,000, 95% CI: 7.8, 26.4), resulting in a 58.9% reduction in the racial disparity.Discussion An intervention to jointly equalize several neighborhood socioeconomic characteristics and neighborhood greenness among men with CaP could reduce racial disparities in mortality. Though this does not reflect a real-world policy, incorporating environmental improvements alongside efforts to reduce socioeconomic disparities could yield greater gains in reducing racial disparities.