A version of this article originally appeared in The Brink.

Twenty-five years ago, 59,000 African American women signed up to join the Black Women’s Health Study launched by the Slone Epidemiology Center at Boston University, when the participants’ median age was in their late 30s. Now, still following those women’s health histories as their median age approaches their mid-sixties, new insights are being revealed about lifelong health risks facing Black Americans. One such finding reveals that experiences of racism are linked with decreased memory and cognition later in life.

“We found an association between experiencing racism—which is a stressor—and lower cognitive function,” says Lynn Rosenberg, professor of epidemiology, an epidemiologist at the Slone Epidemiology Center, and a principal investigator of the Black Women’s Health Study. “There’s a lot of evidence that stressors are related to poorer cognitive function. The part of the brain called the hippocampus, which has a lot to do with memory, is affected by stress hormones called cortisol. Chronic stress increases cortisol levels, which actually causes the tissue of the hippocampus to shrink over time.”

Rates of dementia and Alzheimer’s disease are known to be higher in African Americans than in white Americans, and in many studies, older African Americans perform more poorly on neuropsychological cognition tests compared to white Americans. Exposure to racism is  common among African Americans, with 50 percent or more respondents to a 2017 national survey reporting such experiences. Racism has been associated with increased risks of various conditions that can impair cognition, including depression, poor sleep, type 2 diabetes, and hypertension.

Using data from the Black Women’s Health Study, researchers from BU’s Slone Epidemiology Center quantified the association between experiences of racism and subjective cognitive function—how an individual rates his or her own cognitive function—based on six questions about memory and cognition.

“These are just very simple questions asking about whether a person is having trouble remembering things, or having trouble finding their way around,” says Rosenberg. “It’s a simple cognition test but it is correlated with standard cognition tests used to determine if someone is starting to experience symptoms of dementia.”

Black women who reported experiencing the highest levels of interpersonal racism (for example, hearing racial slurs) had 2.75 times the risk of poor subjective cognitive function as women who reported experiencing the lowest levels of interpersonal racism. Those individuals who experienced the highest levels of institutional racism (for example, having been discriminated against in pay or promotions in the workplace) had 2.66 times the risk of poor subjective cognitive function as those who reported no such experiences.

The results of the study were published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.

“Higher perceived psychological stress is associated with greater subjective memory decline,” says Rosenberg. “Our work suggests that the chronic stress associated with racial discrimination contributes to racial disparities in cognition.”

More research is needed to examine whether exposure to institutional and interpersonal racism accelerates progression to Alzheimer’s disease in Black individuals. Rosenberg says, based on these initial findings of a link between racism and cognition, her team is planning a grant proposal to do just that. She also says she’s interested in studying whether there are any protective factors that could help Black women maintain their cognitive health.

“In terms of cognition, it’s already been established that it’s a good thing to exercise, so we are planning to study the effects of exercise,” Rosenberg says. “Exercise could potentially help counteract the [harmful effects of stress] associated with experiencing racism.”

Rosenberg is also interested in studying whether a healthy diet can combat the effects of stress on brain function. But, she adds, it’s important to remember that exercise and diet are only measures that could potentially be protective on an individual scale.

“Overall, our findings contribute to the growing body of evidence that racism is very bad for people’s health,” Rosenberg says. “This might just be one more bit of information that helps society as a whole realize the harmful effects of what racism does to Black people—and to combat racism.”

This research was supported by the National Cancer Institute, the National Institute on Aging, and the Alzheimer’s Association.

—Kat J. McAlpine (Gina DiGravio also contributed to the reporting of this story)