Social Determinants Data Linked to Higher Risk of Alzheimer’s

After evaluating social determinants data and brain bank samples, researchers have found that people who live in the most disadvantaged US neighborhoods may have a higher risk of developing Alzheimer’s disease-related brain changes.

In a study published in JAMA Network Open, a team from the University of Wisconsin-Madison’s School of Medicine and Public Health noted that neighborhood disadvantage is a key social determinant of health. Neighborhood disadvantage directly reflects the education, income, employment, and housing quality in a certain geographic area.

Past evidence has shown that Alzheimer’s disease-related brain changes including a buildup of abnormal levels of amyloid proteins, can start more than a decade before a person experiences symptoms of the condition. Researchers can identify these early brain changes with advanced brain imaging scans, but the most conclusive way to confirm Alzheimer’s disease is to conduct a brain autopsy upon death.

Because of this, Alzheimer’s disease research centers have brain donor programs that enable Alzheimer’s disease research participants to donate their brains after death.

The study included data from people who volunteered to donate their brains for research at one of two Alzheimer’s Disease Research Center-affiliated brain banks: the Wisconsin Brain Donor Program or the University of California-San Diego Brain Bank. 

Doctors examined donated brain tissue samples for the presence of two kinds of Alzheimer’s disease-related amyloid deposits.

“Our neuropathology team determined the presence of Alzheimer’s disease-related brain changes using extremely sensitive measures,” said Amy Kind, MD, PhD, associate professor of medicine (geriatrics) at the UW School of Medicine and Public Health.

The group then linked the autopsy findings to detailed neighborhood conditions based on the last known residence before death for each of the 447 brain donors in the study. Donors from disadvantaged neighborhoods were less common than donors from wealthier neighborhoods.

The analysis showed that increasing neighborhood disadvantage is linked to increased odds of the presence of Alzheimer’s disease-related brain changes in autopsy results. However, the team conceded that more research is necessary to confirm these findings.

“This is the first study of its kind to link neighborhood disadvantage to the brain tissue markers related to Alzheimer's disease,” said Kind.

“Our work provides a new way to link social determinants to biobanks, and neurons to neighborhoods. It is very exciting and opens opportunities for countless other studies which may further examine the interplay between social factors and fundamental biology, providing opportunities for new therapies and interventions.”

Researchers then evaluated how difficult it might be for people from disadvantaged neighborhoods to access Alzheimer’s disease research center brain bank services. The group leveraged geographic simulation techniques and determined that only 56 percent of the US population lives within 100 miles of a National Institute on Aging-affiliated Alzheimer’s disease research center, and those within reach are most often from wealthier neighborhoods.

This suggests that geographic access is likely difficult for almost half of the country, and is particularly challenging for those living in more disadvantaged neighborhoods. This has poor implications for Alzheimer’s research, the team stated.

“Diverse representation is a known challenge and there is a lot of work going on in the field to improve participation,” said Ryan Powell, PhD, MA, assistant scientist in the UW Department of Medicine Health Services and Care Research Program.

“But with future advancements in treatment and prevention tied to existing data and research, we need to continue to make diverse participation and geographic access to research center services a priority in ongoing strategy.”

The results of the study could potentially help researchers develop precision medicine strategies that help providers identify individuals at increased risk for Alzheimer’s disease and provide tailored treatment and prevention efforts to improve health.

“As the field moves forward, it is important to remember that the evidence needed to fulfill the promise of precision medicine in Alzheimer's disease is only realized by growing biobanks with diverse representation,” Powell said.