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• Posted March 15, 2024

Living in Poor Neighborhoods Ups Risks for Dementia, Early Aging

Doctors looking to help their patients head off dementia may want to ask for their address.

An international team of researchers has linked accelerated brain aging and a higher risk of thinking declines to living in a poorer neighborhood. 

"If you want to prevent dementia, and you're not asking someone about their neighborhood, you're missing information that's important to know," said study leader Aaron Reuben, a clinical psychologist at Duke University, in Durham, N.C.

His team's findings -- published March 14 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association -- suggests the risk of dementia could be reduced if prevention programs were targeted to disadvantaged neighborhoods, and doctors routinely considered where a patient lives. 

Worldwide, about 58 million people have dementia, a number projected to triple by 2050. Alzheimer's is a common form that robs people of their memories and thinking skills.

There is no cure, and efforts to prevent dementia through lifestyle changes like diet and exercise are gaining traction. 

But Reuben's team took a different tack.

"I wanted to understand if there was a geographic patterning to dementia the way there is to longevity, like blue zones," areas where people live longer than average, he said. "A lot of individual choices, like what you eat, what you do for fun or who you spend time with, are constrained by where you live."

Working with collaborators at universities in Michigan and New Zealand, Reuben's team at Duke scoured the medical records and addresses of 1.4 million New Zealanders in search of trends. 

Using government data on average income, employment and education levels as well as transportation accessibility and related factors, researchers ranked each address on 10-point scale from well-off to disadvantaged. 

The upshot: Those in the worst-off areas had a 43% higher risk of developing dementia over 20 years.

Data from a separate study that has documented the psychological, social and physiological health of nearly 1,000 New Zealanders since birth offered more insight into risk. 

By age 45, participants in that study who lived in disadvantaged areas throughout adulthood had measures of poorer brain health, no matter how educated they were or how much money they made.

"It's not just what personal resources you have, it's also where you live that matters," said study co-author Avshalom Caspi, a professor of neuroscience at Duke.

Researchers saw numerous measures of poorer brain health, including smaller nerve cells in information-processing regions, more atrophy and, potentially, microbleeds.

In addition, MRI brain scans showed those from the poorest neighborhoods had brains that appeared three years older than expected for their chronological age, researchers found. 

They also fared worse on tests of memory and reported problems with everyday tasks like remembering how to get to and from familiar places or following a conversation.

Researchers said it's not clear how living in a disadvantaged neighborhood increases a person's dementia risk. Possibilities include poorer air quality, less walkability, fewer social interactions and more stress.

But low-cost interventions like targeted dementia prevention programs or turning vacant lots into parks might help, researchers said.

"If you want to truly prevent dementia, you've got to start early, because 20 years before anyone will get a diagnosis, we're seeing dementia's emergence," Reuben said. "And it could be even earlier."

More information

The U.S. Centers for Disease Control and Prevention has more about links between dementia and lifestyle.

SOURCE: Duke University, news release, March 14, 2024