Higher exposure to racism among marginalized groups may be a substantial driver of racial/ethnic disparities in cognitive health. In a study of 942 community-dwelling adults, mean age 55±11, structural racism was associated with lower episodic memory. Experiences of both interpersonal and institutional racism was associated with lower memory scores, primarily in nonLatinx Black individuals. A higher proportion of nonLatinx Black participants grew up in segregated neighborhoods and experienced both interpersonal and institutional racism. 

“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,” said Jennifer Manly, PhD, professor of neuropsychology at Columbia University Irving Medical Center and the senior author of this work. “Overall, our findings indicate that racism impacts brain health and contributes to the unfair burden of Alzheimer disease in marginalized groups.”

Participants in this study were nonLatinx Black (23%), Latinx (55%), and nonLatinx white (19%) individuals. Structural racism in early life was assessed by residential segregation of the census block group in which participants’ parents lived. Institutional racism was measured with the Major Discrimination Scale (MDS), and daily interpersonal racism was measured with the Everyday Discrimination (ED) scale. 

Cognitive outcomes were derived from a neuropsychological evaluation with the Digit Span, which assesses attention and working memory and the Selective Reminding Test (SRT) was used to assess delayed recall/episodic memory. Fluency was assessed with animal and letter measurers. Age-adjusted linear regression models were used to evaluate the relationships between experiences of racism and cognition. 

 

Another study showed that the effects of racism on cognition are life-long, persisting even past age 90. In a study of 468 people, mean age 92.7±2.3, life experiences of discrimination were stratified as little-to-no discrimination, workplace discrimination (eg, unfair hiring/firing) only, and discrimination across multiple domains (eg, workplace, financial and banking practices, and housing). Scores on cognitive tests every 6 months for a mean 1.2 years were then compared among these 3 groups. 

Those with little-to-no discrimination were Black, Latinx, Asian, and other nonwhite men and women as well as white women. Individuals who reported discrimination across multiple domains–all of whom were Black, Latinx, Indigenous, or Asian–had significantly worse baseline semantic memory compared with those who experienced little-to-no discrimination (-0.24; 95% CI: -0.48, -0.00). In contrast, among those with workplace-only discrimination, who were mostly white men, baseline semantic memory was higher at baseline (0.33; 95% CI: 0.07, 0.58) compared to those with little-to-no discrimination. 

Individuals with workplace-only discrimination also had significantly better executive function (0.28; 95% CI: 0.03, 0.52) at baseline. No differences were observed in baseline episodic verbal memory. Cognition declined over the period of the study, but the rate of change did not differ among the stratified groups. 

Discrimination was measured using the MDS and executive function, verbal episodic memory, and semantic memory were assessed with the Spanish and English Neuropsychological Assessment Scales with scores z-standardized to baseline. Linear mixed models adjusted for age, education, cognitive status (normal/mild cognitive impairment- accounting for recall bias), practice effects, follow-up time, and class*time interactions were generated with random intercepts and slopes associated latent classes of discrimination with cognitive change.

Kristen George, PhD, assistant professor of epidemiology in the Department of Public Health Sciences at University of California, Davis and investigator on the study, a part after the Life After 90 (LA90) study, noted, “These findings highlight that inequities in cognitive function persist after accounting for experiences of major lifetime discrimination,” said George. “Despite the incredible longevity of this group, discrimination has an indelible impact on cognitive health.”