The United States must reduce racial residential segregation if it is to reduce racial disparities in health outcomes, according to a recently published study.

The research on 220 metropolitan areas nationwide between 1980 and 2020 found strong links between trends in racial residential segregation and racial disparities in early death rates from a variety of causes.

The study is the first known to examine the association between changes in racial segregation over time and long-term trends in mortality among non-Hispanic Black and non-Hispanic white people ages 65 or younger.

“This work shows that if we’re able to reduce segregation in communities, we can also expect to reduce health disparities, which is a powerful insight for public health policy,” says Michael Siegel, professor of public health and community medicine at the Tufts University School of Medicine and lead author of the study in the Journal of Racial and Ethnic Health Disparities. “It’s not enough to simply identify disparities; we need to find evidence-based ways to reduce them.”

Drawing on federal data on mortality and demographics in metropolitan statistical areas (MSAs), the study looked at changes in residential segregation between 1980 and 2000 and changes in health outcomes between 2001 and 2018, by which time the researchers hypothesized that measurable differences in mortality would be evident.

The researchers found that both baseline levels of racial residential segregation and ongoing changes in segregation accurately predicted trajectories in the racial disparity in death rates among people younger than age 65 from 12 common causes: breast cancer, colon cancer, lung cancer, prostate cancer, cerebrovascular disease, diabetes, genitourinary disease, HIV, hypertension, respiratory disease, pregnancy, and firearm homicide.