Medical College of Wisconsin Researchers Identify Linkage Between ‘Redlining’ and Mortality After Breast Cancer Diagnosis

Results Published in the Journal of Clinical Oncology Demonstrate the Upstream Effects of Mortgage Discrimination on Widening Disparities for Women’s Health

Milwaukee, June 22, 2021 - Researchers at the Medical College of Wisconsin (MCW) have identified a linkage between contemporary ‘redlining’ (mortgage lending bias based on property location) and mortality after breast cancer diagnosis among older women in the United States. The results, published in the Journal of Clinical Oncology this week, show women residing in more heavily redlined areas experience worse survival rates, after controlling for disease and demographic factors.

This is the first nation-wide study to examine the relationship between contemporary mortgage lending bias and cancer survival. Researchers found redlining differed by race and ethnicity with 79% of non-Hispanic Black and 57% of Hispanic women living in redlined tracts, compared to 34% of non-Hispanic White women. Among 27,516 women with breast cancer, those residing in more heavily redlined areas experienced worse survival based on both all-cause and breast cancer specific mortality, after controlling for disease and demographic factors^[1].

The research shines a light on the upstream effects of discrimination on persisting health disparities for individuals facing a cancer diagnosis.

“Structural racism is a clear upstream driver of cancer disparities. Mortgage lending bias is one form of bias that has caused and reinforced patterns of racial segregation in the United States, with many implications for health and well-being, particularly among people of color,” said Kirsten Beyer, PhD, MPH, MS, associate professor in the division of Epidemiology at MCW’s Institute for Health & Equity and member of the MCW Cancer Center. “We’re doing ongoing research to understand how structural racism contributes to health disparities so we can influence policies and practices to improve patient care and health outcomes for all people.”

According to the MCW study, which received grant support from the National Cancer Institute, the relationship between redlining and survival could have a range of explanations, including poorer access to healthcare and other resources, aspects of housing stability, safety and affordability, experiences of discrimination, environmental exposures, the built environment, economic opportunities, and socioeconomic deprivation.

About the methodology

A redlining index using Home Mortgage Disclosure Act data (2007-2013) was linked by census tract with a SEER-Medicare cohort of 27,516 women aged 66-90 years with an initial diagnosis of stage I-IV breast cancer in 2007-2009 and follow-up through 2015. Cox proportional hazards models were used to examine the relationship between redlining and both all-cause and breast cancer specific mortality, accounting for covariates.

All individuals studied were enrolled in Medicare Parts A and B and not in an HMO for at least 12 months prior to their breast cancer diagnosis to allow for the assessment of comorbidity. The sample was further restricted to those residing in a Metropolitan Statistical Area (MSA) with known census tract (n=27,654). Both all-cause and breast cancer specific mortality were assessed. Patients for whom a cause of death was unknown (n=118) were excluded from analyses of breast cancer specific survival. Survival models were used to examine relationships and control for other variables impacting survival.

The researchers acknowledge the efforts of the National Cancer Institute; the Office of Research, Development and Information, CMS; Information Management Services (IMS), Inc.; and the Surveillance, Epidemiology, and End Results (SEER) Program tumor registries in the creation of the SEER-Medicare database.