The statistics are shocking: African American adults are twice as likely to develop Alzheimer’s disease as white adults. Why is this?
Genetic factors come to mind as an explanation. But two new studies presented recently at the Alzheimer’s Association International Conference in San Diego have come up with a surprising and quite different answer.
The research suggests that the higher risk of Alzheimer’s suffered by people of color may boil down to racism.
Different Forms Of Racism
Not all racism is the same. There’s interpersonal racism, which involves encounters between individuals. There’s also structural racism, which relates to discrimination from wider political and social disadvantages within society. And there’s institutional racism, which refers to processes, attitudes and behaviors that discriminate through unwitting prejudice, ignorance, thoughtlessness, and stereotyping.
The two studies presented at the conference in August show experiences with all three types of racism are linked to lower memory scores and worse cognition throughout midlife and old age, especially among black individuals.
Stress – A Likely Contributor
Neuropsychologists from Columbia University in New York carried out the first study. It involved 942 American men and women, of which half were Latino, about a quarter (23 percent) were black and 19 percent were white.
Researchers found those who suffered from interpersonal and institutional racism scored lower on memory tests, with the strongest association for black participants.
Structural racism was linked to lower episodic memory, a type of long-term memory that involves recollection of personal experiences. This occurred among both ethnic groups in the study.
Senior study author Jennifer Manly explained the results, saying, “Chronic exposure to racism and interpersonal discrimination among marginalized communities leads to stress that affects the body and influences physiological health, and likely contributes to the development of cognitive decline.
“Overall, our findings indicate that racism impacts brain health and contributes to the unfair burden of Alzheimer’s disease in marginalized groups.”
Super Agers Also Affected
The second study, from the University of California, examined people over 90 from different ethnic groups. Each participant completed a questionnaire on his or her experiences with discrimination throughout life. Each participant also underwent three different cognitive assessments over a period of 15 months.
Those who faced the most wide-ranging discrimination suffered from the worst semantic memory when compared with those who experienced little to no discrimination. Semantic memory is the type of long-term memory involved with recalling general knowledge and information.
Interestingly, differences in the experience of racial discrimination didn’t impact cognitive decline over time, however. Lead author Kristen George had this to say: “These findings highlight that among the oldest old, inequities in cognitive function persist after accounting for experiences of major lifetime discrimination. Despite the incredible longevity of this group, discrimination has an indelible impact on cognitive health.”
These are not the first studies to investigate the effects of racism on brain health.
Nearly Three Times More Likely To Suffer Memory Loss
In 2020, researchers from Boston University looked at the experiences of racism on subjective cognitive function among 17,320 participants in the prospective Black Women’s Health Study.
They found that compared to those experiencing the lowest levels of interpersonal racism, women suffering the highest levels were 2.75 times more likely to report deteriorating cognition, or more frequent confusion or memory loss. And those reporting the highest levels of institutional racism had 2.66 times the risk of decline in their memory.
The researchers also pointed to chronic stress resulting from racism as a likely factor to account for their findings.
The next set of studies examined changes in the brain following encounters with racism.
Brain Imaging Studies
Two studies from Emory University in Atlanta used brain imaging to dig further into the association between racism and memory loss.
In the first study, published in JAMA Psychiatry last year, researchers recruited 55 black women with an average age of 57. They followed these women for five years and found that those with more experiences of racial discrimination had a greater response in brain regions related to threat vigilance and regulation of threat response.
Clinical neuropsychologist Negar Fani, who led the research said, “Over time, there may be a physical and emotional cost to overburdening these systems, which could result in an increased risk for later brain health problems.”
In the second study, published this year in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, the Emory team recruited 79 black women to analyze fractional anisotropy (FA), long, fatty tracts that connect distant brain regions. Changes in FA reflect structural disruption in white matter, which as we’ve reported before, shrinks with age and that shrinkage is related to memory loss.
Results showed women experiencing more discrimination displayed lower FA in two tracts that connect the two hemispheres of the brain, demonstrating that racial discrimination affects the brain’s microstructure.
Dr. Fani said, “Here we see a pathway through which racist experiences [have] effects on select stress-sensitive brain pathways.”
This research is not surprising to me. We’ve often written about how physical and mental stress can take a toll on your health, including by damaging your memory. Anything you can do to better manage your stress level will help your memory in spades, as will eating a healthy diet and getting regular exercise.