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A New Study Reveals A Link Between Alzheimer’s Disease & Environmental Risks

Coping with violent crime, neighborhood trust, and living costs may increase Alzheimer’s risk in low-income neighborhoods

By Sherri Snelling

Against the backdrop of the nation's highest inflation rate in 40 years, increased costs for gas, food, and household utilities, and rising violent crime rates, one study presented at the Alzheimer's Association International Conference (AAIC) earlier this year shows that among lower-income communities of color, individual reactions to these life stressors may impact cognitive function and white matter disease that can increase Alzheimer's risk.

Homes near a steel plant spouting air pollution. Next Avenue, environmental risks, alzheimer's, dementia, pollution
Industrial air pollution near homes in Clairton, Pennsylvania.  |  Credit: via PBS

The preliminary research findings conducted by neuropsychology researchers at the University of Texas Southwestern Medical Center are one of the first studies to ask how participants felt about their neighborhoods regarding safety, trust, and access to health care and other affordable services.

The Alzheimer's Association reports African Americans have twice the risk, and Latinos have 1.5 times the chance as their white counterparts when developing Alzheimer's.

"Our goal was to understand why there is a disproportionate risk for certain communities of color."

Numerous studies have shown a connection between socioeconomic status (SES is defined by income level, occupation, and years of education) and environmental factors (such as air pollution, lack of quality medical care, transportation needs, and food deserts) and Alzheimer's risk.

For instance, one study found a decreased risk of dementia and Alzheimer's in adults over 60 who lived in biophilic-designed neighborhoods (nature elements, trees).

"What is unique about our study is we decided we get more rich information by asking how participants felt about SES and environmental factors rather than assuming their response just based on their income status, years of education or where they lived," said Anthony Longoria, clinical psychology doctoral candidate at the University of Texas Southwestern.

"This is a more personable way of looking at socioeconomic status to understand individual experiences. Our goal was to understand why there is a disproportionate risk for certain communities of color," he added.

Researchers took a probability-based randomized cross-sectional sample of 3,858 participants from the Dallas Heart Phase Study 2 with 59% female respondents and 51% Black, and 14% Hispanic to represent the broader population and asked a series of questions:

  • Have they witnessed, read, or heard about violence in their community in the last six months? 
  • Do they feel close-knit in their community, are their neighbors willing to help, and do they share the same values? 
  • Do they think there is adequate access to fresh food, affordable heating, and quality medical care? 

Researchers also measured cognition using the Montreal Cognition Assessment (MoCA), and the participants underwent MRI brain scans for additional data analysis.

The results indicate that Black and Hispanic participants scored lower on cognitive testing when they perceived less access to food, heating, medical care, and increased exposure to violence. In contrast, the white study participants had no decline in cognitive measures.


Reviewing the MRI data, among the Black and Hispanic participants in the study, perceived neighborhood disadvantages and economic status showed more changes in white matter volume (WMV) and hyperintensities (WMH) in the brain that affect memory, processing speed, balance, and other mobility issues. 

"We know having more education, and higher income can be protective, but there is only so much that we can do about those things."

While WMV declines over time in normal aging, an individual with lower WMV and higher WMH indicates reduced blood flow to the tissues. This is associated with a higher risk for dementia and vascular health issues.

Reported lower income and education levels were associated with higher WMH in the overall sample; however Black female participants saw an even more significant increase in WMH related to questions about violence. 

For Hispanic male participants, questions about neighborhood trust showed lower WMV, and access to medical care showed lower WMV in white women. All of these are indicators of higher Alzheimer's risk.

"We know having more education, and higher income can be protective, but there is only so much that we can do about those things," said Heidi Rosetti, neuropsychologist, UT Southwestern associate professor, and advisor on the study. 

"If we can understand the relationship between risk of dementia and environmental factors in vulnerable communities, such as neighborhood safety, this could help inform public policy and guide public health interventions."

These preliminary findings are intriguing because they were conducted before George Floyd's death in Minneapolis in 2020 and the ensuing civil unrest in American cities, the coronavirus pandemic, and the recently reported 9.1% consumer price index – showing the highest inflation rates since 1981, according to the U.S. Department of Labor. 

Longoria is currently underway with the next phase of the study, which is to reassess these participants several years after tremendous societal and economic turmoil.

"Some of the data that we saw at the conference look at things like anticipatory stress, but also the personal experiences of racism as additional stressors, and we see changes in the immune system and changes in inflammation measures which may be part of the linkage to Alzheimer's risk," said Heather Snyder, vice president, Medical & Scientific Relations at the Alzheimer's Association.

Educational Tools and Programs Address Dementia Risk 

Two years ago, the Lancet Commission Report on Alzheimer's Risk identified 12 modifiable lifestyle factors representing 40% of worldwide Alzheimer's cases. The theory is that addressing these 12 lifestyle factors may prevent or at least delay the disease: 

  • High blood pressure
  • Unaddressed hearing impairment
  • Obesity
  • Diabetes II
  • Smoking
  • Lack of physical activity
  • Lower levels of education
  • Depression
  • Lack of social engagement
  • Air pollution
  • Excessive alcohol consumption
  • Traumatic brain injury, including injury from falls

The Alzheimer's Association also reports women represent 66% of all Alzheimer's cases.

There is no reason to wait to be diagnosed with Alzheimer's when we know we may have the tools today to delay or prevent it.

In another study, a diet of ultra-processed foods representing more than 20% of daily caloric intake can increase the risk for dementia. High salt, sugar, and trans fatty acid foods increase the risk of heart disease, diabetes, obesity, and cancer. 

Still, this new study found that men and women who ate the most ultra-processed foods had a 28% faster rate of cognitive decline than those who ate the least amount of overly processed food.

"There is no reason to wait to be diagnosed with Alzheimer's when we know we may have the tools today to delay or prevent it," said Dr. Rudy Tanzi, a 2018 Next Avenue Influencers in Aging, vice-chair of Neurology and director of the Genetics and Aging Research Unit at Massachusetts General, in an interview conducted last year. 

"In the same way we treat early signs of higher cholesterol and hypertension for possible heart disease and stroke risk and address lifestyle factors that can lead to diabetes, we need to apply the same proactive rather than reactive approach to Alzheimer's," Tanzi said.

Online Memory Questionnaire

One of the tools Tanzi recommends is an online memory questionnaire and information site. "BrainGuide will empower patients and doctors with a way to break the silence that has lingered over this disease for far too long," said Tanzi.

BrainGuide was launched last year to help address the 60% of dementia cases that go undetected until later stages of the disease. More than 200,000 people, 79% of women over age 65, have taken the free, private memory questionnaire via either voice or web bot that provides personalized results on cognitive and brain health status. 

Although not a diagnostic tool, it is meant to encourage users to talk to their primary care doctor if there are areas of concern. The site launched simultaneously in English and Spanish, focusing on culturally relevant information for diverse populations.

Powered by the UsAgainstAlzheimer's network that includes LatinosAgainstAlzheimer's and AfricanAmericasAgainstAlzheimer's, BrainGuide is also conducting grassroots community programs.

For instance, in the greater Atlanta area, they are partnering with ALTER, a coalition of African American faith-based organizations, Black Health Matters, local university Black sorority and fraternities, and Emory University to increase education around brain health and dementia risk.

Photograph of Sherri Snelling
Sherri Snelling 
Sherri Snelling
 is a corporate gerontologist, speaker, and consultant in aging and caregiving. She is the author of “Me Time Monday – The Weekly Wellness Plan to Find Balance and Joy for a Busy Life” and host of the "Caregiving Club On Air" podcast.
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