The COVID-19 mortality rate for Black Americans is triple that for white Americans. This appalling difference in mortality has helped to awaken Americans to the large racial health disparities that exist in the United States. These disparities are longstanding and well-documented, and include asthma, chronic liver disease, type 2 diabetes, heart disease, stroke, dementia and Alzheimer’s Disease.
While researchers have long considered genetic, physiological and behavioral explanations for racial health disparities, it has become clear that societal-level factors play a critical role. Of great importance among societal factors is structural racism—longstanding policies that favor white over Black Americans in housing, education, healthcare and criminal justice.
Experiences of racism are a highly prevalent stressor for African Americans. The physiological effects of stress are well-known and include adverse effects on cognition. Evidence is accumulating that experiences of racism are associated with increases in the risk of conditions that can impair cognition, including depression, poor sleep, type 2 diabetes and hypertension.
Connecting Racism to Cognitive Health
Few studies have had the data needed to evaluate the contribution of experiences of racism to disparities in cognitive health. The Black Women’s Health Study (BWHS), conducted by researchers at the Slone Epidemiology Center at Boston University (including the authors of this article), has collected such data and recently assessed the association of experiences of racism with cognition.
The BWHS was initiated in 1995 when 59,000 African American women enrolled by completing health questionnaires; since then every two years we have sent participants health questionnaires, which they fill out and return. In 1995, the participants had a median age of 38 years. By 2015, about half of the participants were at least 60 years old or older, ages at which people may first become aware of losses in their cognition.
In 2015, we added six questions to the BWHS questionnaire that assessed such problems, providing a measure of subjective cognitive function (SCF): three questions asked about difficulties in remembering things (recent events; a short list of items; trouble remembering things from one second to the next) and three questions asked about other difficulties in cognition (following spoken instructions; following a group conversation; finding your way around familiar streets).
Women who had experienced the most racism were much more likely to have poor subjective cognitive function scores.
In 1997 and again in 2009, we asked participants about their experiences of racism. To assess interpersonal racism, we asked how frequently (ranging from never to almost daily) the participant experienced the following: “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,” and “People act as if they are better than you.”
We also asked about structural racism—whether the participant had ever experienced racism in any of six situations (on the job, in housing, by police, getting medical care, at school, in the courts). With this data, we constructed “scores” for experiences of interpersonal and structural racism.
Our analysis included 17,320 BWHS participants who in 2015 were ages 55 or older; 60 percent reported no problems on the six cognition questions (which we classified as “good” SCF), and 12 percent reported difficulties with three or more of the six cognition questions (which we classified as “poor” SCF). Using appropriate statistical methods, we estimated the risk of having poor SCF compared to good SCF in women at the highest compared to the lowest levels of racism. Our analyses took into account characteristics relevant to cognition, such as prior heart disease. We found that women who had experienced the most racism were much more likely to have poor SCF scores. In particular, women at the highest level of the interpersonal racism score had a risk of poor SCF that was 2.8 times that of women at the lowest level of the score, and women who had experienced structural racism in at least three of six situations had 2.7 times the risk of poor SCF compared to women who had never experienced racism in any of the six situations.
Stress Plays a Role in the Equation
Stress is probably a key player in the association of racism with cognition. Chronic stress is associated with reduced hippocampal volume, and the hippocampus is a brain area involved in memory (source; source). Stress also contributes to depression and to poor sleep, both of which impair cognition. Further analyses in our study suggested that part of the association of racism with SCF was attributable to these two conditions.
Our study was large, statistically powerful and used validated measures of experiences of racism and of cognition. However, the study was limited by use of a subjective measure of cognitive function and by lack of repeated measures of cognition. In order to assess how experiences of racism will impact the trajectory of cognitive aging in BWHS study participants, we will need to collect objective measures of cognition that are repeated over time. We are piloting the use of a smartphone-based app to get quick and convenient objective measures of cognition, and plan to expand our assessment of experiences of racism and cognition in the coming years as dementia and Alzheimer’s Disease occur in study participants as they age.
The anger and unrest surrounding the murder of George Floyd and the COVID-19 pandemic have forced Americans to confront structural racism and its enormous impact on the lives and health of African Americans. Our study contributes to the evidence showing that structural racism is a key—perhaps the key—driver of health disparities.As a society, we must continue strive to eliminate the structures which perpetuate and maintain racism. We must also identify and support the self-care strategies necessary to cope with and survive societal inequity and racism.
Patricia Coogan, DSc, is a research professor of Epidemiology; Lynn Rosenberg, ScD, is a professor of Epidemiology; and Yvette Cozier, DSc, is an associate professor of Epidemiology, all at the Slone Epidemiology Center at Boston University.