Living in disadvantaged neighborhoods linked to higher dementia risk, study finds

Americans who live in neighborhoods with less socioeconomic advantage may have a higher risk of dementia, according to a new study published Wednesday in JAMA Neurology.

This can be true regardless of an individual’s background, according to the study, which found that people living in areas of the U.S. with the lowest levels of income, education, employment, and housing quality had a 1.17 times higher risk of developing dementia compared to residents of the least disadvantaged areas.  

The study is the first to connect neighborhood deprivation with a higher risk for dementia in a large, diverse population, building on previous research that found similar links in smaller, more homogenous groups in Minnesota and northern California.

The fact that people living in more disadvantaged neighborhoods tend to face more stressors and have fewer resources — factors that are associated with adverse health outcomes — may explain part of the link with dementia, according to researchers. People in less-advantaged areas may also have limited access to activities that the study’s researchers say can be good for brain health, such as crafting or using computers.

“It’s a strong reminder of how entrenched structural inequities are within our neighborhoods, and how neighborhood conditions and contexts are so fundamental to impacting an individual’s health,” said Ryan Powell, assistant professor of medicine at the University of Wisconsin School of Medicine and Public Health, who was not involved in the study. “With this we can now add dementia incidence to the long and growing list of related outcomes that are impacted by neighborhood-level factors.”

In this retrospective cohort study, presented at the Alzheimer’s Association International Conference in Amsterdam this week, researchers looked at data from more than 1.6 million U.S. veterans aged 55 and older who had received health care between October 1999 and September 2021. The researchers followed up with veterans for an average of 11 years, until they developed dementia, died, or had their last medical visit. 

They then analyzed the levels of deprivation in the neighborhoods where veterans lived, drawing on 2015 data from the University of Wisconsin’s Neighborhood Atlas. Researchers adjusted for age, sex, race, and ethnicity, as well as comorbidities ranging from diabetes and traumatic brain injury to depression and post-traumatic stress disorder.

Neither race nor health issues explained the higher risk of dementia for people in disadvantaged neighborhoods, said Christina Dintica, a postdoctoral scholar in dementia epidemiology at the University of California, San Francisco and one of the authors of the study.

Researchers lacked access to certain data, the authors noted, such as how the neighborhoods in which veterans lived might have changed over time. They also couldn’t account for how factors like gentrification, crime rates, or the number of health facilities in a given neighborhood might affect its level of disadvantage. And since the study looked only at only veterans, the findings aren’t necessarily generalizable to the U.S. population. 

Future studies should examine neighborhoods as a social determinant of health over people’s entire lifespans, according to the researchers. After all, living in a certain neighborhood in middle or older age might not reflect the resident’s earlier life experiences in neighborhoods that had different income levels. 

STAT has previously reported on how stressful experiences during childhood — particularly those based on income — act as toxic stressors, disproportionately affecting the brain development of Black children. Studying how social and environmental vulnerability at different life stages impacts brain health and risk of dementia would further advance the scope of their research, the authors wrote.

Also noteworthy is that, even within a veteran population in which all people theoretically have access to health care, the study found disparities based on the neighborhoods in which people lived. This suggests more resources should be allocated to health-care facilities in deprived neighborhoods, according to Dintica.

These particular findings are “huge,” Powell said, adding that they “should serve as a call to action in terms of … groundbreaking health equity policy” to provide resources to the neighborhoods that most need them.