Abstract B066: Neighborhood-level factors and breast cancer survival in U.S. Black women
Authors: Holder Etienne X. , Xu Nuo N. , Palmer Julie R. 
Published: December 2023

Background: Black women living in the United States (U.S.) are 40% more likely to die from breast cancer than White women. There are multiple contributors to this disparity. One factor that warrants further research is the neighborhood environment. The legacy of structural racism, including redlining mortgage practices, has resulted in Black Americans being more likely to live in disadvantaged and economically deprived neighborhoods, regardless of their own individual socioeconomic (SES) status. We investigated the interplay of neighborhood-level and individual-level factors with breast cancer mortality in a cohort of breast cancer cases from the prospective Black Women’s Health Study. Methods: Included were 1,781 Black women with invasive breast cancer diagnosed at stages I-III. Data on individual-level factors were obtained by questionnaire and death data were obtained from the National Death Index. Participant addresses, updated every two years, were geocoded and linked with U.S. census data and American Community Survey data to create three neighborhood variables. Neighborhood SES and Neighborhood Disadvantage were based on factor analysis of items related to income, wealth, employment, etc., and provided a numerical score at the block group level, which was then analyzed as quartiles. The Index of Concentration at the Extremes (ICE) grouped locations into three income-based groups representing concentrated privilege, middle, and concentrated deprivation in each census tract.  Participants were followed to time of breast cancer death, death from any other cause, or end of follow-up. Time to breast cancer death was calculated in months. Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). All analyses were adjusted for age at diagnosis and stage at diagnosis. Results: During follow-up from 1997-2019, there were 464 deaths, of which 286 deaths were from breast cancer. The HR for living in the most disadvantaged neighborhood relative to the least disadvantaged was 1.71 (95% CI: 1.21, 2.42), and the HR for lowest quartile of neighborhood SES relative to highest was 1.44 (95% CI: 1.01, 2.06). Lastly, for women living in concentrated deprivation as compared to women living in concentrated privilege, the HR for breast cancer mortality was 1.64 (95% CI: 1.22, 2.20). Further control for body mass index, vigorous activity, smoking, alcohol intake, and initial treatments did not reduce the magnitude of the associations. In addition, the observed associations were similar for women with estrogen receptor positive and estrogen receptor negative breast cancer. Conclusion: In this study of U.S. Black women, those who lived in disadvantaged neighborhoods were more likely to die from their breast cancer, even after accounting for stage at diagnosis and lifestyle factors. The findings suggest that other attributes of the neighborhood environment, including chronic stress (e.g., from noise, violence, lack of green space) and distance to treatment facilities likely play a role. 

Citation Format: Etienne X. Holder, Nuo N. Xu, Julie R. Palmer. Neighborhood-level factors and breast cancer survival in U.S. Black women [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B066.