Summary: New research indicates that living in disadvantaged neighborhoods is associated with higher levels of biological markers linked to inflammation and Alzheimer’s disease. In a long-term study of 334 older adults, researchers observed increased tau and YKL-40 in cerebrospinal fluid and rising C-reactive protein in blood among people from less advantaged communities, suggesting that neighborhood conditions may influence biological processes relevant to Alzheimer’s risk.
The study establishes an association rather than a direct cause-and-effect relationship: it connects neighborhood disadvantage with measurable changes in biomarkers that are tied to neurodegeneration and systemic inflammation.
Key Facts:
- Elevated tau levels: Participants from more disadvantaged areas had higher cerebrospinal fluid concentrations of tau, a core biomarker associated with Alzheimer’s pathology.
- Increased inflammation marker: Greater neighborhood disadvantage correlated with larger annual increases in high-sensitivity C-reactive protein (CRP), a widely used blood marker of systemic inflammation.
- Findings independent of demographic factors: Associations persisted after adjusting for age, sex, and years of education, indicating neighborhood effects beyond these common risk variables.
Source: AAN
Overview: A study published June 25, 2025, in Neurology examined whether long-term exposure to disadvantaged neighborhood conditions is linked to biological indicators of inflammation and Alzheimer’s disease. Researchers measured blood and cerebrospinal fluid biomarkers, conducted neuroimaging, and tracked cognitive performance over multiple years to evaluate how neighborhood context relates to markers of brain health.
The research team, led by Angela L. Jefferson, PhD, of Vanderbilt University Medical Center, analyzed data from 334 adults with an average age of 73. Participants completed baseline testing and follow-up visits at 18 months, three years, five years, seven years, and nine years. Blood samples were taken at each visit, and a subset of 180 participants also provided cerebrospinal fluid samples at up to five time points. Brain imaging and cognitive testing were included to provide a more complete picture of neurological status over time.
Neighborhood disadvantage was quantified using measures such as local income levels, unemployment rates, educational attainment, and disability prevalence. Participants living in neighborhoods ranked higher for disadvantage showed greater evidence, at baseline, of elevated tau in spinal fluid—a protein that accumulates in the brains of people with Alzheimer’s disease.
In addition to tau, the study found higher cerebrospinal fluid levels of chitinase-3-like protein 1 (YKL-40), which is associated with neuroinflammation. Over the follow-up period, people from more disadvantaged neighborhoods experienced faster increases in blood CRP, indicating a trend toward growing systemic inflammation that could interact with brain health over time.
“These results suggest that chronic stressors tied to neighborhood conditions may contribute to inflammation and to biological changes linked with Alzheimer’s disease,” said Dr. Jefferson. She emphasized that the findings point to possible pathways through which social and environmental factors influence neurodegenerative risk, and that these pathways deserve further investigation in diverse populations.
The study controlled for age, sex, and education, and the associations between neighborhood disadvantage and biomarkers remained significant, strengthening the evidence that community context plays an independent role. Quantitatively, every 10-percentile increase in neighborhood disadvantage was associated with an additional 0.05 mg/L annual rise in CRP, after adjustment for the covariates considered in the analysis.
Clinical implications include the potential for healthcare providers to consider neighborhood context when assessing risk and recommending inflammation-reducing strategies, such as stress management, physical activity, and other lifestyle modifications. The authors also recommend greater inclusion of residents from disadvantaged communities in prevention and treatment research to ensure findings apply broadly.
Limitations noted by the researchers include a study sample that was predominantly white and relatively well-educated and that overall lived in less disadvantaged areas than the U.S. average. Because of this, results may not generalize to all populations. The study was funded by the Alzheimer’s Association and the National Institute on Aging.
About this Alzheimer’s disease research news
Author: Renee Tessman
Source: AAN
Contact: Renee Tessman – AAN
Image: The image is credited to Neuroscience News
Original Research: The findings will appear in Neurology