A national analysis published in JAMA Network Open found that Black people who live in counties with more Black primary care physicians live longer, providing compelling evidence that diversity in medicine may aid in reducing longstanding racial health disparities.

While other studies have shown that Black patients treated by Black doctors are more satisfied with their health care and more likely to agree to and receive preventive care, according to a STAT News article, this study is the first to link a higher prevalence of Black doctors to longer life expectancy and lower mortality in Black patients.

For the study, researchers analyzed more than 3,000 counties during 2009, 2014 and 2019. The analysis showed a higher life expectancy in the 1,618 counties that had at least one Black primary care physician.

In an editorial accompanying the study, Monica Peek, MD, a primary care physician and health equity researcher at UChicago Medicine wrote: “That a single Black physician in a county can have an impact on an entire population’s mortality, it’s stunningly overwhelming.… It validates what people in health equity have been saying about all the ways Black physicians are important, but to see the impact at the population level is astonishing.”

For every 10% increase in Black primary care physicians, life expectancy increased by about one month, according to the study. What’s more, every 10% increase in Black primary care physicians resulted in a 1.2% lower disparity in all-cause mortality between Black and white people.

The study indicated that Black doctors may be more likely to treat low-income and underinsured patients and to take new Medicaid patients compared with physicians of other races or ethnicities. Peek added that Black physicians may also be more likely to perform unpaid health-related work outside the health care system. What’s more, the study authors suggested that implicit bias may be a factor when doctors treat patients outside their racial and ethnic groups.

“This is adding to the case for a more diverse physician workforce,” Michael Dill, a coauthor of the study and director of workforce studies at the American Association of Medical Colleges, told STAT. “What else could you ask for?”