Living in disadvantaged neighborhoods linked to Alzheimer’s biomarkers

People living in more disadvantaged neighborhoods may be more likely to have biomarkers for inflammation and Alzheimer's disease, according to a study published June 25, 2025, in Neurology^®, the medical journal of the American Academy of Neurology. The study does not prove that neighborhood factors cause these biomarkers: it only shows an association.

Studies have shown that living in less advantaged neighborhoods may increase your risk for Alzheimer's disease, but we haven't known much about the mechanisms underlying this risk. These results suggest that neighborhood disadvantage increases the risk of inflammation, which may play an early role in the development of Alzheimer's disease, as well as biomarkers for the disease itself."

Angela L. Jefferson, PhD, study author of Vanderbilt University Medical Center in Nashville, Tennessee, and a member of the American Academy of Neurology

The study involved 334 people with an average age of 73. Participants underwent blood tests, brain scans, and tests of their cognitive skills at the beginning of the study and again after 18 months, three years, five, seven, and nine years. A total of 180 people from the group also had samples of their cerebrospinal fluid drawn at those same time periods up to five years.

Neighborhood status was determined by factors such as income, employment, education and disability.

At the beginning of the study, people who lived in areas with greater neighborhood disadvantage were more likely to have elevated levels of tau, which is a biomarker related to Alzheimer's disease, in their cerebrospinal fluid.

"We found that greater neighborhood disadvantage was associated with greater levels of tau, a key biomarker of Alzheimer's disease," said Jefferson. "This observation suggests that living in more disadvantaged neighborhoods may result in more stressful exposures that drive neurodegeneration, resulting in an increased risk for developing Alzheimer's disease."

Researchers also found participants had elevated levels of chitinase-3-like protein 1, called YKL-40, a biomarker of brain inflammation, in their spinal fluid. These observations existed despite considering other factors that could affect levels of biomarkers, such as older age, female sex, and lower levels of formal education.

When looking at the tests over time, researchers found that greater neighborhood disadvantage was related to faster increases in levels of high sensitivity C-reactive protein (CRP) in the blood, which is a well- established biomarker for inflammation. Every 10 higher percentile ranking in neighborhood disadvantage was associated with 0.05 milligrams per liter greater increase in inflammation measured by CRP each year.

"Based on these results, healthcare providers may consider neighborhood disadvantage when they are working with people who could benefit from strategies to reduce inflammation levels through lifestyle interventions, such as stress reduction techniques and exercise," Jefferson said. "Continued efforts should also be made to include people who live in disadvantaged neighborhoods in studies on prevention and treatment of Alzheimer's disease."

A limitation of the study was that most participants were white people who were well-educated and lived in less disadvantaged neighborhoods compared to the United States overall, so the results may not apply to other groups.

The study was supported by the Alzheimer's Association and the National Institute on Aging, which is part of the National Institutes of Health.