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Abstract Background: Historic redlining, a 1930s-era form of residential segregation, has been associated with breast cancer related outcomes, but research is lacking on how known present-day breast cancer risk factors are related to historic redlining. Objective: To describe the co-occurrence of historic redlining with present-day neighborhood-level breast cancer risk factors and evaluate geographic patterning across the US. Methods: All US neighborhoods historically graded (grades A-D) were included. We dichotomized neighborhoods as redlined if they had a historic redlining score ≥2.5 (grades C and D). We used census tract-level prevalence data from 2019 Population Level Analysis and Community EStimates (PLACES) and 2014-2016 air pollution data from Environmental Justice Index (EJI). Neighborhoods were classified as high risk for each factor if they were in the highest two quintiles for adverse risk factors: obesity, binge drinking, smoking, no leisure physical activity (LPA), lacking health insurance, high school education, low median income, concentrated Black population, and air pollution; in the lowest two quintiles of protective factors: mammography and routine checkup; and if the built environment is old (median year houses built 1980). We estimated tetrachoric correlations and conducted a factor analysis to group variables. We created an overall risk score and domain-specific scores for each neighborhood to quantify the number of factors that met the high-risk threshold. Averages of these scores were evaluated according to redlining status. Finally, we used GIS to spatially examine the co-occurrence of high-risk status and redlining. Results: Redlining status was moderately correlated with smoking, no LPA, high school education, low income, and lacking health insurance and was weakly correlated with binge drinking, obesity, concentrated Black population, low mammography, low routine checkup, air pollution, and old built environment. Correlations between social and behavioral factors were strong but weak for healthcare and environmental factors. We identified two domains through factor analysis: (1) behavioral + socioeconomic status (SES) and (2) healthcare. Air pollution and old built environment did not load onto either domain. Across the US, redlined neighborhoods scored significantly higher on all present-day neighborhood risk scales than non-redlined neighborhoods: 30.8% higher on the overall scale, 31.8% higher on the behavior + SES subscale, and 16.4% higher on the healthcare subscale. Maps showed that high-scoring neighborhoods tended to overlap with historically redlined, particularly D-grade, neighborhoods, though there was heterogeneity in patterns depending on scale and US region. Discussion: Redlined neighborhoods have more high-level breast cancer risk factors compared to non-redlined neighborhoods. Our findings suggest that associations between historic redlining and specific factors may be region-dependent, therefore interventions aimed at reducing redlining-based cancer disparities may need to be tailored to the community. Citation Format: Sarah M. Lima, Tia M. Palermo, Helen CS Meier, Jared Aldstadt, Henry L. Taylor Jr, Lili Tian, Heather M. Ochs-Balcom. Exploring the co-occurrence of historic redlining and present-day breast cancer risk factors abstract. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A053.
Lima et al. (Sat,) studied this question.