Early life experiences associated with racial differences in cognition

Negative early life experiences, such as attending segregated schools, significantly contribute to cognitive decline and cognition differences between older black and white Americans, according to a new study led by researchers at the Yale School of Public Health.

The studypublished in JAMA Internal Medicineis the first to look at the impact of school segregation on cognition in later life using a large representative sample of the US population, said lead author Xi Chen, associate professor of public health (health policy) at the Yale School of Public Health (YSPH) and associate professor at Yale’s Institution for Social and Policy Studies.

Previous research in this area has focused on the duration of education. The current study assessed the quality of education provided and individuals’ personal experiences of education, including whether they attended segregated schools.

“This is a groundbreaking study based on that aspect,” Chen said.

The findings are important because the differences in dementia rates between black and white Americans are stark: Black older adults are about twice as likely as white older adults to have Alzheimer’s disease or another form of dementia, according to the Alzheimer’s Association.

The study could have important implications for policymakers and health professionals, Chen said. Many currently identified risk factors for dementia and cognitive impairment occur in mid-life or later. But focusing on early life can be more efficient and promote equality.

“Our study shows that promoting equity in education can reduce racial disparities in dementia in later life,” Chen said. Studies show that the return on investment in education could be higher than controlling risk factors in middle age and later, such as diabetes and hypertension, he added.

The research could also be useful for general practitioners. Doctors monitor patients’ health to understand their risk of dementia, but understanding patients’ childhoods can also be helpful.

“If a patient in the South were educated in segregated schools, that could be a strong signal to prioritize screening for cognitive impairment,” Chen said.

For the study, Yale researchers collected data from 1,634 non-Hispanic black and 7,381 non-Hispanic white participants in the Health and Retirement Study, a longitudinal study of about 20,000 people over age 50 in the U.S. overseen by the University of Michigan.

The researchers analyzed results from the study’s core survey, which assessed cognitive function and cognitive impairment, as well as a separate life history survey that asked questions about childhood experiences, including family relationships and finances, traumatic experiences and education. Information from personal interviews and genetic factors related to cognition were also included in the analysis.

On a 27-point scale, black participants’ scores on cognitive tests were found to be 2.3 points lower than white participants’ scores: 13.5 points compared to 15.8 points, respectively. Black participants were also more than twice as likely to have cognitive impairment as white participants: 33.6% compared to 16.4%, respectively, according to the study.

Black participants were also more likely to have difficult life experiences in childhood, the researchers said. These challenges include having to move due to family financial issues, needing financial support from family members, and experiencing trauma. The study found that black participants and their parents generally received less education than white participants. They were also more likely to have less “enriching” educational experiences, and nearly two-thirds of black participants attended segregated schools before college, the researchers found.

The researchers used a sophisticated statistical method to understand the differences between groups to evaluate how total early life experience and specific early life experiences were related to cognitive differences and cognitive decline among black and white participants.

The study found that total early life experiences were associated with 61.5% of the difference in cognitive scores and 82.3% of the higher rate of cognitive impairment among black participants. The single life experience with the greatest effect was residence in segregated schools until university, especially during primary school. Segregated education prior to college was associated with 28.8% of the difference in cognitive scores and 39.7% of the difference in cognitive decline, according to the study.

In an accompanying editorial in JAMA Internal Medicine, Dr. Reagan W. Durant, the magazine’s associate editor for diversity, equity and inclusion, emphasized the importance of the study given the high levels of de facto racial segregation in schools that still exist today – driven primarily by economic disparities within communities.

“Although state-sponsored school segregation was legally abolished by the 1954 U.S. Supreme Court decision, Brown v. Board of Education, and the decades of tireless efforts to integrate schools, the effects of early school segregation are still relevant today in our assessment of education and teaching. its contemporary and future effects on health outcomes,” Durant wrote.