Study on over 17,000 Black women shows how racism changes the brain

Decades of data show experiencing racism can wage a serious psychological toll, jeopardize health, and even accelerate biological aging. Racism isn't just a social disease — it actually harms mental and physical well being over time.

New research, analyzing the cognitive function and everyday experiences of over 17,000 Black women, adds another harmful side effect to the list: cognitive deficits linked to racial discrimination.

Racism can hamper brain function in detrimental and lasting ways, scientists report.

Experiencing both daily and institutional racism was linked with worsened cognition — poorer memory and processing speeds. Women reporting the highest level of daily racism had 2.75 times the risk of poor cognitive function as women reporting the lowest level of daily racism.

Women experiencing the highest frequency of institutional racism had 2.66 times the risk of poor cognitive function as those who reported no such experiences. Here, experiencing daily racism was defined by experiences like encountering racism at a restaurant, while institutional racism was defined as experiencing racism in institutional settings, like treatment by police.

Senior author Lynn Rosenberg, an epidemiologist at Slone Epidemiology Center at Boston University, puts it simply: "Racism is bad for the health of the individual on the receiving end."

"Everyone is affected by stressors, but African Americans have the additional heavy burden of the stress of racism," Rosenberg tells Inverse. "Given the large literature documenting the harmful health effects of stressors, it should not be a leap for people to realize that racism has harmful health effects as well."

Rosenberg and her team's study was published Monday in the journal Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring.

Racism and health — Discrimination is prevalent in American life. In 2017, more than half of Black respondents to a nationally representative survey reported experiences of institutional racism such as workplace discrimination in pay or promotion, as well as daily interpersonal racism such as having experienced racial slurs.

Each time someone experiences discrimination, they go into fight or flight, the body's evolutionarily embedded stress response. The heart pounds, breath quickens, and senses heighten to prepare the body to run or face a threat. But when threats pop up on a daily or weekly basis, they over-activate this physiological response.

In turn, this creates chronic stress that, over time, influences health. Racism has been linked to increased risks of various conditions that can impair cognition, including depression, insomnia, hypertension, and diabetes.

"Racism is a stressor that has been associated with other adverse outcomes, such as increased risk of type 2 diabetes," Rosenberg says. "Given the known effects of stressors on health, including cognition and memory, it is entirely expected that racism would have a harmful effect on cognition and memory among individuals who have experienced racism in the course of their lives."

To quantify how experiences of racism influence brain function, the team used data from the Black Women's Health Study. Rosenberg is also the principle investigator of that study.

It began in 1995. Initially, the team recruited 59,000 Black women between the ages of 21 and 69. The group enrolled completed extensive health questionnaires, capturing lifestyle factors, reproductive history, and medical conditions. Every other year, the same group filled out subsequent health surveys through 2015.

In 1997 and 2009, 17,320 participants also filled out surveys detailing their experiences with racism and discrimination. Researchers asked, “In your day-to-day life, how often have any of the following things happened to you?” followed by five specific situations:

• “You receive poorer service than other people in restaurants or stores.”
• “People act as if they think you are not intelligent."
• “People act as if they are afraid of you."
• “People act as if they think you are dishonest."
• “People act as if they are better than you.”

Researchers captured participants' experiences of institutional racism by asking:

“Have you ever been treated unfairly due to your race in any of the following circumstances? (1) Job (hiring, promotion, firing), (2) Housing (renting, buying, mortgage), (3) Police (stopped, searched, threatened), (4) In the courts, (5) At school, (6) Getting medical care."

Based on these responses, researchers calculated people's daily and institutional racism "scores."

In 2015, 17,320 participants were additionally asked to take a subjective cognitive function (SCF) test, which included six questions about memory and cognition. This survey is designed to screen for dementia via the telephone.

Both daily and institutional racism was linked with poorer subjective cognitive function (SCF). That means people who deal with racism and discrimination on a regular basis may be slower to recall memories or process new information.

Women experiencing the highest daily racism scores in 2009 had 2.75 times the risk of poor SCF as women with the lowest scores. Women with high scores in both 1997 and 2009 had over four times the risk.

Meanwhile, women reporting institutional racism in five to six domains had 2.66 times the risk of poor SCF as those who reported no such experiences.

The findings suggest experiencing racism can hamper cognitive function over a lifetime and may hasten the development of dementia and Alzheimer's.

The findings are stark, but Rosenberg notes, the number of studies of racism in relation to cognition and memory can be "counted on one hand."

"It may take many studies before individuals other than African Americans understand the widespread harmful effects of racism on the health of individuals exposed to it," Rosenberg says. "More are needed, as well as more studies of racism in relation to other health outcomes."

Protecting brain health — Researchers haven't pinpointed the exact causal factors driving this troubling cognitive disparity. Based on this study and other evidence, they hypothesize that experiencing racism appears to hinder cognitive function by causing chronic stress, depression, and insomnia.

Chronic stress due to racism may also structurally change the hippocampus, a part of the brain involved in learning and memory. It's also possible health conditions related to stress, like diabetes, may have harmful effects on cognition and memory.

"The health costs are monumental," Rosenberg says. "Societal action is needed to lessen the amount of racism experienced by African Americans and other targets of racism."

Abstract:

Introduction: We hypothesized that frequent experiences of racism among African American women would adversely affect subjective cognitive function (SCF), based on the established association of psychological stress with memory decline.

Methods: We used multinomial logistic regression to quantify the association between experiences of racism and SCF, based on six questions, among 17,320 participants in the prospective Black Women’s Health Study.

Results: The multivariable odds ratio (OR, 95% confidence interval [CI]) for poor com- pared to good SCF among women at the highest versus the lowest level of daily racism (eg, poorer service in stores) was 2.75 (2.34 to 3.23); for the same comparison among women at the highest level of institutional racism (eg, discriminated against in housing) relative to the lowest, the OR was 2.66 (2.24 to 3.15). The associations were mediated, in part, by depression and insomnia.

Discussion: Experiences of racism, a highly prevalent psychosocial stressor among African Americans, were associated with lower SCF.