Nearly seven million Americans are living with dementia, and the number of individuals with cognitive impairment is expected to rise with the current acceleration of population aging.
Recognizing this trend, Dr. Xi Chen, PhD, associate professor of health policy and economics at the Yale School of Public Health, is exploring long-term strategies to counter the rising rate of dementia.
Chen recently led a study on how racial segregation in schools may influence the development of dementia in later life. The study appears in the peer-reviewed journal JAMA Network Open.
“We most often focus on something immediately addressable, like modifiable risk factors in the medical setting,” said Chen, the study’s senior author. “But this study shows that something can have a long-term consequence, even after 70 years.”
Despite the 1954 U.S. Supreme Court ruling in Brown v. Board of Education of Topeka, Kansas —which found that segregated schools were inherently unequal and a violation of the Fourteenth Amendment of the U.S Constitution — American schools continue to struggle with heightened levels of segregation. Research has shown that approximately 40% of Black students attend schools that are 90% to 100% non-white.
“In America, school segregation is still prevalent,” said Chen, a faculty fellow at Yale’s Alzheimer’s Disease Research Center and a PEPPER scholar at Yale’s Claude D. Pepper Older Americans Independence Center. “It may not be talked about, but it's still there, and in some school districts, it is getting worse.”
This study shows that something can have a long-term consequence, even after 70 years.
Dr. Xi Chen, Yale School of Public Health
To explore the effects of segregation on cognition, Chen analyzed the historical school records of more than 20,000 study participants. This allowed him to capture an objective measure of the impacts of segregation, rather than relying on participants’ self-reports.
Chen found that Black individuals who were exposed to segregation during their school years had lower cognitive ability and a higher prevalence of dementia in later life, after accounting for other variables. One of the ways that segregated education impacts cognitive ability is by influencing future physical health conditions, such as increasing the chances of diabetes or an addiction to smoking, Chen said.
“When children are segregated in school, they experience discrimination, and this can increase the likelihood that they will drop out,” said Chen. “Limited years of schooling may affect their future behavior and health.”
While Chen’s study explored only Black and white segregation, he explained that the findings can likely be extrapolated to any type of segregation. And while types of segregation may vary across the world, the effects of discrimination are similar, he said. Segregation leads to stress, which can lead to changes in the immune system and cause inflammation in the brain, no matter whether this discrimination is racial, ethnic, or something else, Chen said.
That stress-related brain inflammation can lead to a cascading series of events. Brain inflammation can result in lower levels of schooling which in turn can result in poor physical health which in turn can contribute to long-term cognitive problems, Chen said.
Chen hopes that clinicians can leverage patients’ early-life educational circumstances to promote more targeted screening, prevention, and management of cognitive disorders. Identifying people at risk of dementia in clinical settings using information based on their schooling could help prioritize limited clinical resources for these higher-risk groups, he said.
Chen’s study is believed to be the first to use such data to examine the relationship between school segregation and cognitive outcomes in later life. In future work, Chen and his research team hope to investigate the effects of segregation on Hispanic Americans, as well as collaborate with neuroscientists to further explore the findings.
The study was a collaboration between Yale School of Public Health’s Department of Health Policy and Management and Yale School of Medicine’s Department of Internal Medicine.
The study was co-led by Zhuoer Lin, a recent PhD alumnus of Yale School of Public Health and now an assistant professor at University of Illinois Chicago, and Yi Wang, a postdoctoral associate at Yale School of Medicine. Thomas M. Gill, the Humana Foundation Professor of Geriatric Medicine at Yale, is a co-author. The study was supported in part by National Institutes of Health grants from the National Institute on Aging.