Neighborhood change shapes Alzheimer’s risk over time
Over Time, Living in a Neighborhood with Increasing Segregation Can Affect Risk for Alzheimer's Disease
Alexandra L. Clark, Abbey M. Hamlin
Background and Purpose
Conditions within neighborhoods may affect residents’ biological processes that lead to Alzheimer’s disease. In racially segregated neighborhoods, residents often face fewer resources and more economic hardship. These conditions can increase long-term stress, which in turn can raise the risk of other problems tied to brain health. Segregated environments can also have rich social connections, which can help to maintain cognitive strength and resilience over time.
This research brief is based on a study that examined how living in a racially segregated neighborhood in mid and late life and how changing levels of segregation over time relate to risk for Alzheimer’s disease. Unlike previous studies, many of which looked only at where people lived in late life, this study, done in Austin, Texas, used a life course approach and accounted for changes in residential segregation over a 20-year period.
Key Findings
Patterns of residential segregation across the 20-year study align with national trends. Racial segregation generally declined in the Austin area, but declines were not uniform across racial and ethnic groups. Concentrations of Non-Hispanic White residents increased in centrally located neighborhoods, while concentrations of non-Hispanic Black and Hispanic residents declined in many of these areas and increased in peripheral neighborhoods. These shifts often coincide with rapid population growth, economic restructuring, and rising housing costs in expanding metropolitan areas. The reorganization of segregation may redistribute some populations from inner-city neighborhoods to more affordable surrounding areas.
Where people lived later in life may be less important than earlier mid-life exposure to segregated neighborhoods. Segregation levels in 2020 were not linked to any of the three biomarkers for Alzheimer’s disease.
When controlling for socioeconomic context and historic segregation levels, living in neighborhoods with increasing segregation over time was associated with worsening brain health. Increases in segregation over a 10-year period were associated with higher levels of GFAP (noting inflammation). Increases in segregation over a 20-year period were associated with higher levels of NfL (noting breakdown of brain cells).
There were no associations between segregation levels, change in these levels over time, and the biomarker, which notes buildup of harmful protein deposits on the brain. Segregation levels may influence some biological pathways of Alzheimer’s disease, such as the breakdown of brain cells and inflammation, but not others like protein deposits (AB42/40).
Implications for Population Health and Aging
Declining brain health may reflect the cumulative biological toll of increasing racial segregation, the concentration of at-risk individuals into under-resourced areas, or continued patterns of disinvestment. Neighborhoods may be a critical target for preventing dementia. Policies that reduce segregation or prevent worsening conditions may help lower risk for dementia over time. Investments in housing, economic opportunity, and community stability may protect brain health, especially in communities experiencing rapid change.
Data and Methods
Participants were recruited from 2022 to 2025. The study included 119 adults aged 50 and older living in the Austin, Texas area who completed cognitive testing in English. Researchers linked participants’ residential addresses to U.S. Census data from 2000, 2010, and 2020.
The researchers measured segregation using the dissimilarity index, which represents the proportion of one group that would need to relocate to achieve an even population distribution across areas. They calculated changes in segregation over time (2000, 2010, 2020) and used two indicators to assess a neighborhood’s economic disadvantage and one indicator to measure racial and ethnic composition.
Using the participants’ blood samples and other tests, the researchers measured genetic risk, health status, and Alzheimer’s-related biomarkers (NfL, GFAP, AB42/40). These three biomarkers note different parts of the disease process (brain cell loss, inflammation, and buildup of harmful proteins on the brain). The researchers also assessed participants’ cognition and levels of anxiety and depression.
The authors used statistical models that adjusted for age, sex, race, education, genetic risk, and health conditions. These models explored whether living in a neighborhood with specific economic, racial, and ethnic characteristics during midlife and late life and changes in segregation levels were linked to biological markers tied to Alzheimer’s disease.
Worsening racial segregation over time was linked to warning signs in the blood for Alzheimer’s Disease. These signs included the breakdown of brain cells and inflammation in the brain.
About the Authors
Alexandra L. Clark, alexandra.clark@austin.utexas.edu, is assistant professor of psychology and faculty affiliate in the Center for Aging and Population Studies (CAPS) at The University of Texas at Austin. Abbey M. Hamlin is a PhD Student in Clinical Psychology at UT Austin.
Funding for Research and Disclaimer
This research was supported by the National Institute on Aging (R03 AG085241), CAPS at UT Austin (P30AG066614), and a National Science Foundation Graduate Research Fellowship Program award (DGE-2137420). The content is solely the authors’ responsibility and does not necessarily represent the official views of the funding agencies.
Read the Original Paper
Clark, A. L., & Hamlin, A. M. (2026). Life course neighborhood conditions and change: A 20-year examination of neighborhood context and associations with Alzheimer’s disease biomarkers in late life. Alzheimer's & Dementia 22(4). DOI: 10.1002/alz.71382