Summary: New research shows that neighborhood conditions — from pollution and housing to economic opportunity — may directly affect brain health and dementia risk. Analyzing brain scans and biomarkers from 679 adults, scientists found that people living in areas with higher social and environmental disadvantages showed signs of reduced brain thickness, altered blood flow, and white matter changes.
These biological differences were most pronounced among Black participants from highly burdened neighborhoods. The findings highlight that brain health is not only shaped by genetics and lifestyle but also by the broader environment and social systems we live in.
Key Facts:
- Neighborhood Effects: Higher neighborhood disadvantage scores were linked to brain changes tied to dementia risk.
- Biological Evidence: Altered brain structure, reduced blood flow, and vascular changes were observed in people from high-burden areas.
- Equity Implications: Results show social and environmental inequitie
Source: Wake Forest University
The conditions where you live may influence your brain health and risk for dementia, according to a new study from Wake Forest University School of Medicine.
The study, published today in Alzheimer’s & Dementia: Behavior & Socioeconomics of Aging, a journal of the Alzheimer’s Association, found that individuals living in neighborhoods with higher levels of social vulnerability, environmental injustice and socioeconomic disadvantage showed measurable differences in brain structure and function.
“This study is consistent with other research showing that the state of the social environment in which people live can shape their brain health in profound ways,” said Timothy Hughes, Ph.D., associate professor of gerontology and geriatric medicine at Wake Forest University School of Medicine and senior author.
Researchers analyzed data from 679 adults enrolled in the Healthy Brain Study at the Wake Forest Alzheimer’s Disease Research Center. Each participant underwent brain scans and blood tests to detect early signs of Alzheimer’s disease and related dementias.
The team then compared these results with three national-level tools that assess neighborhood conditions at the level of the zip code: the Area Deprivation Index, Social Vulnerability Index and Environmental Justice Index.
Higher scores on these indices, reflecting greater neighborhood burden of the social determinants of health, were linked to changes in dementia-related biomarkers, especially among Black participants whose neighborhoods experienced the most burden of the social determinants.
These dementia-related biomarkers included a thinner outer layer of the brain, white matter changes representing vascular disease, reduced blood flow and more uneven circulation, all of which may contribute to memory and cognitive decline over time.
“This study is one of the first to connect a variety of place-based social factors with advanced biological markers of dementia,” said Sudarshan Krishnamurthy, a sixth-year M.D.-Ph.D. candidate and lead author.
“It shows that the conditions and environment in which people live — such as access to clean air, safe housing, nutritious food and economic opportunity — may leave a lasting imprint on brain health.”
The study contributes to a growing body of evidence that social and environmental factors are not just background influences but central to understanding and addressing Alzheimer’s disease and related dementias.
Krishnamurthy emphasized the policy relevance of the findings.
“If we truly want to improve brain health across all communities, we must look beyond individual choices and hone in on the broader systems and structures that shape health at the neighborhood level.”
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 higher levels of social vulnerability, pollution, and poverty were linked to measurable differences in brain structure and circulation that increase dementia risk.
A: It’s one of the first to directly connect environmental and social disadvantage with biological markers of dementia, showing that inequality is literally imprinted in the brain.
A: Addressing systemic inequities—like housing, environmental justice, and access to nutritious food and healthcare—could help reduce 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
Relationships between place-based social determinants of health (SDoH) and Alzheimer’s disease and related dementias biomarkers are emerging.
METHODS
Linear regressions examined associations of area deprivation index (ADI), social vulnerability index (SVI), and environmental justice index (EJI) with biomarkers among Healthy Brain Study participants (n = 679), 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 in Black compared to White participants. Among Black participants, we found relationships between higher SVI and EJI with higher CBF variability, higher ADI with lower mean CBF, and higher ADI and SVI with lower cortical thickness.
DISCUSSION
Place-based SDoH may partially capture effects of structural racism on brain health and affirm the importance of structural interventions in addressing SDoH.
