Racism increases the risk of a stroke in American Black women, according to the largest follow-up study on the health of Black women in the U.S.

A 22-year Boston University study which chronicled 48,375 Black women from who were free of cardiovascular disease and cancer when the study began in 1997. By the time the study ended in 2019, those who reported racist interactions on the job (in hirings, promotions and firings), or with police (being stopped, searched or threatened) or in their attempts to secure housing (renting, buying, mortgage applications) were found to have a 38 percent higher risk of having a stroke than those who did not.

During the span of the study, 1,664 women suffered strokes, the majority coming from those who reported the racist interactions — even after accounting for demographic and vascular risk factors, which means it took into account U.S. Department of Health and Human Services findings that Black adults are 50 percent more likely to have a stroke than White adults and Black women two times more likely than White women.

“Our findings suggest that the high burden of racism experienced by Black U.S. women may contribute to racial disparities in stroke incidence,”  said Dr. Shanshan Sheehy, a Boston University assistant professor of medicine.

While several large studies have investigated stroke risk factors among American Black men and women, the Boston University researchers say their study stands out.

“Our study provides direct evidence on perceived racial discrimination at the interpersonal level in relation to subsequent occurrence of stroke,” said Sheehy.