Study: Diabetes prevalence in American neighborhoods is influenced by historic and contemporary structural racism

BUFFALO, N.Y. -- Diabetes is more prevalent in neighborhoods where historic residential redlining occurred and where contemporary structural racism persists, according to a new study by University at Buffalo population health researchers.

Published on April 6 in JAMA Network Open, the research is the first study to examine diabetes prevalence in U.S. neighborhoods by taking into account direct and indirect associations of both historic redlining and contemporary structural racism.

The study was based on more than 15,000 U.S. census tracts in 157 counties within all 50 states and Washington, D.C.

Redlining originated with the Home Owners Loan Corporation, which was created in 1933 as part of the New Deal. It ranked the supposed “creditworthiness” of neighborhoods in American cities by designating each neighborhood with a color; redlined neighborhoods were considered the worst credit risks and were home to racial and ethnic minorities, primarily African Americans.

“This cross-sectional study provides evidence that both historic and contemporary measures of structural racism are directly associated with higher diabetes prevalence,” says Leonard E. Egede, MD, senior author and Charles and Mary Bauer Endowed Chair of Medicine in the Jacobs School of Medicine and Biomedical Sciences at UB.

Neighborhoods shape the health of residents

Egede notes that while traditional diabetes research has focused on clinical risk factors and individual-level social determinants, such as income, education or insurance status, growing evidence shows that these factors themselves are influenced by the neighborhood environments of residents.

“Neighborhoods shape daily opportunities for healthy eating, physical activity, stress exposure and access to health care — key determinants of diabetes prevention, control and management,” he says. “Furthermore, structural racism, defined as the ways in which societies foster racial discrimination through mutually reinforcing systems, is a specific type of structural inequity linked to racial and ethnic disparities in health outcomes.”

He adds that evidence suggests that structural racism has had a broad and enduring influence on diabetes. “However, less is known about how historic forms of racism interact with contemporary structural inequities to shape diabetes prevalence across geographic regions in the present day,” he says.

The new study examines how diabetes prevalence across geographic regions today is driven by both historic forms of racism and contemporary structural inequities. While redlining is one of the most commonly used measures of historic structural racism, Egede explains that contemporary structural racism is measured through the Structural Racism Effect Index (SREI), which generates a composite score across nine domains of influence: built environment, criminal justice, education, employment, housing, income and/or poverty, social cohesion, transportation and wealth.

“The finding that contemporary structural racism is the strongest mediator between Black race and diabetes prevalence suggests that structural inequities are not only historically rooted but are actively maintained through current policies and systems,” he explains.

Additional historic forms of racism (such as the impact of Jim Crow laws on employment and educational opportunities, unequal access to health care due to segregated hospitals) and contemporary structural factors (including disproportionate environmental exposures and unequal access to insurance) also may continue to influence the prevalence of diabetes in historically redlined neighborhoods.

Relevance to Buffalo

While the study’s focus was national, Egede notes its findings are especially relevant to Buffalo, given the city’s well-documented legacy of redlining and segregation, as well as the substantial health disparities that persist today.

“Neighborhoods on the East Side were systematically labelled as ‘hazardous’ and denied access to mortgage lending and investment,” says Egede, “and Buffalo remains one of the most segregated cities in the United States.”

Egede says these findings reinforce the need both locally and nationally for targeted policies that expand the reach and equity of social support programs, prioritize the design and evaluation of multilevel interventions to address these drivers, and equip health care systems with the skills and partnerships to address upstream drivers of diabetes disparities, such as systemic inequities in income, education and health care access.

Interventions that can help reduce diabetes rates are those that can expand the reach and equity of existing social support programs. Egede says these include the Supplemental Nutrition Assistance Program, Temporary Assistance for Needy Families, and the Low-Income Home Energy Assistance Program.

“Similarly, expanding Medicaid at the state level can help remove financial barriers to care for underserved populations,” he says. In addition, investment in integrated care models that address both medical and social needs, such as medical-legal partnerships and housing support services, is also essential to mitigate the structural inequities that contribute to diabetes risk.

At the clinical level, Egede says there needs to be a shift from merely screening for social risks to actively resolving patient-defined social needs that interfere with diabetes self-management and outcomes through medical-social partnerships.

Co-authors with Egede are Jennifer A. Campbell, PhD, associate professor, and Rebekah J. Walker, PhD, associate professor and chief, Division of Population Health, both in the Department of Medicine in the Jacobs School.  

The research was funded by the National Institute of Diabetes and Digestive Kidney Disease and the National Institute for Minority Health and Health Disparities.