Summary: New research indicates that neighborhood conditions — including pollution, housing quality, and economic opportunity — can directly influence brain health and the risk of dementia. By analyzing brain scans and blood biomarkers from 679 adults, researchers discovered that individuals living in areas with greater social and environmental disadvantage showed signs of reduced cortical thickness, altered cerebral blood flow, and white matter changes linked to vascular injury.
These biological differences were especially apparent among Black participants who lived in the most burdened neighborhoods. The findings underscore that brain health is shaped not only by genetics and personal lifestyle, but also by the broader social and physical environments where people live.
Key Facts:
- Neighborhood effects: Higher scores on neighborhood disadvantage measures were associated with brain changes that relate to increased dementia risk.
- Biological evidence: Researchers observed thinner cortex, altered cerebral blood flow (including greater variability), and white matter changes consistent with vascular disease in people from high-burden areas.
- Equity implications: The results reveal how social and environmental inequities are reflected in measurable brain health differences, highlighting a role for place-based interventions.
Source: Wake Forest University
Where we live may influence brain health and dementia risk, according to a new study from Wake Forest University School of Medicine.
Published in Alzheimer’s & Dementia: Behavior & Socioeconomics of Aging, a journal of the Alzheimer’s Association, the study compared advanced biological markers of Alzheimer’s disease and related dementias with measures of neighborhood-level social and environmental disadvantage. Investigators linked differences in brain structure and circulation to the social and environmental conditions in participants’ neighborhoods.
“This research aligns with other studies showing that the social conditions where people live can profoundly shape brain health,” said Timothy Hughes, Ph.D., associate professor of gerontology and geriatric medicine at Wake Forest University School of Medicine and senior author on the paper.
The team analyzed data from 679 adults enrolled in the Healthy Brain Study at the Wake Forest Alzheimer’s Disease Research Center. Participants underwent neuroimaging and blood tests to detect early signs of Alzheimer’s disease and related dementias. Investigators then compared those biological measures with three national indices that evaluate neighborhood conditions by ZIP code: the Area Deprivation Index (ADI), the Social Vulnerability Index (SVI), and the Environmental Justice Index (EJI).
Higher ADI, SVI, and EJI scores — which indicate greater neighborhood burden across social determinants of health — were associated with alterations in dementia-related biomarkers. These associations were most pronounced among Black participants, who, in this study, tended to live in neighborhoods with higher measured burdens.
Specifically, higher neighborhood burden correlated with a thinner cortical layer of the brain, increased white matter abnormalities consistent with small vessel vascular disease, lower mean cerebral blood flow, and greater variability in blood flow. Together, these changes represent biological pathways that may contribute over time to memory loss and cognitive decline.
“This is among the first studies to link a range of place-based social factors directly with advanced biological markers of dementia,” said Sudarshan Krishnamurthy, a sixth-year M.D.-Ph.D. candidate and lead author. “The findings suggest that the environments people inhabit — including access to clean air, safe housing, healthy food, and economic opportunity — can leave a lasting imprint on brain health.”
The authors emphasize the public-health and policy implications: efforts to improve brain health across communities should extend beyond individual behavior change and address the broader systems and structures that shape neighborhood conditions.
Funding: This research was supported by the National Institutes of Health (grants F30 AG085932 and P30 AG07294) and the American Heart Association (grant 24PRE1200264).
Key Questions Answered:
A: Neighborhoods with greater social vulnerability, environmental burdens, and economic deprivation were linked to measurable differences in brain structure and cerebral circulation that are associated with higher dementia risk.
A: It directly connects neighborhood-level social and environmental disadvantage to biological markers of Alzheimer’s disease and related dementias, demonstrating that inequality at the community level can be reflected in brain health.
A: Addressing systemic inequities—such as improving housing quality, reducing pollution, expanding access to nutritious food and healthcare, and increasing economic opportunities—could help lower dementia risk across populations.
About this dementia and brain health research news
Author: Myra Wright
Source: Wake Forest University
Contact: Myra Wright – Wake Forest University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Associations of place-based social determinants of health with biomarkers of Alzheimer’s disease and related dementias” by Timothy Hughes et al. Alzheimer’s & Dementia: Behavior & Socioeconomics of Aging
Abstract
Associations of place-based social determinants of health with biomarkers of Alzheimer’s disease and related dementias
INTRODUCTION
Evidence is emerging that place-based social determinants of health (SDoH) — the social, economic, and environmental characteristics of neighborhoods — are associated with biomarkers of Alzheimer’s disease and related dementias.
METHODS
The study used linear regression to examine associations between three neighborhood-level indices — the Area Deprivation Index (ADI), Social Vulnerability Index (SVI), and Environmental Justice Index (EJI) — and a range of biomarkers among Healthy Brain Study participants (n = 679), with analyses stratified by racialized groups. Neuroimaging biomarkers included cortical thickness, brain parenchymal volume, white matter hyperintensity volume, cerebral blood flow (CBF) and its variability in gray matter. Plasma biomarkers included glial fibrillary acidic protein (GFAP), amyloid-beta ratios, and phosphorylated-tau 181.
RESULTS
Place-based SDoH measures were higher among Black participants compared to White participants. In Black participants, higher SVI and EJI were associated with greater CBF variability; higher ADI was associated with lower mean CBF; and higher ADI and SVI were linked to reduced cortical thickness.
DISCUSSION
These findings suggest that place-based SDoH may partially reflect the effects of structural racism on brain health and underscore the importance of structural, community-level interventions to address social determinants of health and reduce dementia risk.