Structural Racism Linked to Breast Cancer Disparities

July 18, 2022

Living in areas that were not historically redlined is associated with more favorable breast cancer outcomes among non-Latina White women. The findings underscore how racial and ethnic disparities in breast cancer are perpetuated by practices like redlining that disproportionately benefited white communities, not just negatively impacted communities of color.

The study is published in the journal JAMA Network Open. Adana A. M. Llanos, PhD, associate professor of epidemiology at Columbia University Mailman School of Public Health, is senior author. The first author is Jesse J. Plascak, PhD, Ohio State University.

The 1930s Home Owners’ Loan Corporation (HOLC) mortgage security redlining maps of major metropolitan housing markets assessed neighborhoods using four grades: “best,” “still desirable,” “definitely declining,” or “hazardous,” the latter of which were given to neighborhoods partially based on the presence of “foreign-born” and “negro” residents. Mortgage lending based on racial and ethnic composition has contributed to poorer social and economic well-being among Black and African American individuals and other people of color that persist today.

The researchers used data from the New Jersey State Cancer Registry to analyze breast tumor progression and breast cancer–specific death among more than14,000 women diagnosed from 2008 to 2017 and followed up through 2019. Participants included all primary, histologically confirmed, invasive breast cancer cases diagnosed among women aged 20 and older who resided in a HOLC-graded area of New Jersey.

The researchers found that white women currently living in neighborhood areas that were not redlined had more favorable breast cancer outcomes—lower odds of late stage at diagnosis, lower odds of high tumor grade, lower odds of triple-negative breast cancer (TNBC) subtype, and lower hazards of breast cancer–specific death. Among women from minoritized racial and ethnic groups, these associations were not observed. Previous research elsewhere has linked residence in historically redlined neighborhoods with worse health outcomes.

Residence in non-redlined areas might reflect historical access to better resources (e.g., education, income, employment, wealth) that contribute to more favorable breast cancer outcomes only among white populations. This might be due to intergenerational transmission of wealth and socioeconomic status not afforded to individuals residing in redlined areas, who tend to be from racial and ethnic minority groups and marginalized communities. Another potential factor is interpersonal discrimination, a psychosocial stressor and potential driver of mechanisms that are linked to poorer cancer outcomes, including inflammation and epigenetic changes. Previous research shows that residents who are among the numerical minority and self-identify as part of a minoritized racial or ethnic group report greater interpersonal discrimination as the proportion of their neighbors who identify as white increases. These experiences might offset any protective benefits of living in a non-redlined area.

“Epidemiologic studies typically frame the role of racial discrimination or racism as having a negative effect on people racialized as Black or brown who were targets of harmful practices and policies. Implied, but less discussed, is the potential for cancer inequities based on race also persist because of historical – and current – efforts to preserve perceived benefits within neighborhoods that were overwhelmingly comprised of people identifying as white,” says Llanos.

“As we discussed in our study, neighborhoods of mostly white people might therefore have benefited regardless of any harmful effects experienced by individuals of a minoritized racial or ethnic group residing in redlined areas,” adds Plascak.

A full list of co-authors is available in the study article.

Funding for the study was provided by the National Cancer Institute (CA072720, A214805, CA214805) and Rutgers Cancer Institute of New Jersey. The authors report no conflicts of interest.