Home is where the brain is

"Stroke Belt" hometowns affect brain health for life — study

New data reveals a troubling trend across the Southeast.

Your hometown does more than shape the way you speak or your access to opportunities — it influences your brain health, even if you move away. According to a new nine-year analysis of over 20,000 Americans, growing up in a specific region of the United States increases people’s risk of experiencing health conditions linked to cognitive impairment when they are older.

Older people who spent their entire young adulthood (from birth to age 30) within the "Stroke Belt" were 51 percent more likely to develop cognitive impairment compared to people who never lived there, according to preliminary research. At the same time, people who grew up elsewhere but move to the region later in life don’t experience these negative health outcomes to the same extent.

The most concerning states — Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Tennessee — make up what scientists call the “Stroke Belt,” a term coined in 1965. The region is linked to a number of population-wide health problems, including diabetes, heart disease, and brain disease. This new unpublished study, along with a growing body of research, suggests that these health issues are a result of a complicated range of factors that begin to affect individuals in the Stroke Belt early in life.

"These findings suggest that early residence in the Stroke Belt during childhood or early adulthood may increase the risk of cognitive impairment, no matter where you live in later adulthood,” Virginia Howard, lead author of the study and epidemiologist at the University of Alabama at Birmingham School of Public Health, tells Inverse.

Howard explains that this is likely because the risk factors underlying stroke and cognitive decline — like smoking and high blood pressure — may be more common in the Stroke Belt than elsewhere in the country, even among children and young adults.

Howard and her team will present their preliminary research at the American Stroke Association's International Stroke Conference on February 19.

The geography of health

To parse out how health outcomes play out across the Southeast and other parts of the country, Howard and her team tracked and compared the cognition changes of 11,488 people living in the Stroke Belt to 8,949 people living outside of it.

All these people were initially recruited between 2003-2007 and enrolled in an ongoing population-level study called Reasons for Geographic And Racial Differences in Stroke (REGARDS). The group was over 45-years-old when they joined the study and were an average of 65-years-old at the time of this new study. When the initial study kicked off, no one had a history of stroke and all were deemed “cognitively intact” based on memory and thought-processing tests.

For the next nine years, Howards’ team called these participants annually and conducted neurological tests designed to capture cognitive function. Essentially, the researchers examined how sharp they were and if they’d experienced any adverse cognitive events like a stroke or Alzheimer’s as the years passed. The team also documented where the participants had lived throughout their life (inside or outside the Stroke Belt).

After this nine-year analysis, the research team rounded up the data and analyzed it, observing where people lived at different points in their life. The geographic differences and resulting health outcomes they saw were stunning — and concerning.

Those who spent all of their childhood (from birth to age 18) outside the Stroke Belt but now live inside it were 24 percent less likely to develop cognitive impairment, compared to the lifelong residents of the region. Meanwhile, the people who spent all of their early adulthood (ages 19-30) outside the Stroke Belt (and now live there) were 30 percent less likely to develop cognitive impairment than lifelong Stroke Belt residents.

Meanwhile, people currently living outside the Stroke Belt who spent their entire young adulthood within the region were twice as likely to develop cognitive impairment than people who never lived in the Stroke Belt.

That means that even if people move away from the region as adults, those early years continue to threaten their brain health.

People who spent part of childhood or young adulthood living in the Stroke Belt showed the same heightened risk as people who lived there for their entire early life.

These numbers don’t equate to an early death sentence for people growing up in the Southeast. But they do emphasize the importance of teaching young people that their choices can manifest in long-term health outcomes, Howard says. To check out your hometown's rates of stroke, use the CDC's interactive map.

Starting early

Even though they’ve observed this phenomenon for over 50 years, scientists still aren’t positive about the driving factors behind this trend. Howard speculates that diet, physical activity, smoking habits, and blood pressure, are involved in protecting — as well as damaging — brain health, starting from childhood and adolescence. During these periods, children are exposed to and learn habits and lifestyle factors that linger into adulthood, Howard explains.

“Change of what is learned comes later in life, and the damage or benefit of an unhealthy or healthy lifestyle may have already set the course,” Howard says.

Map shows the total stroke mortality rates across the United States for people over age 35. Higher rates are seen across the Stroke Belt.CDC

Past Stroke Belt research focuses on where people die from strokes, not where they live out their first few decades. Howard’s new research spotlights these pivotal years, suggesting early intervention could lead to big health wins later on. She advises that preventative strategies to protect people’s brains should be started as early in life as possible.

“The general public, community members, and policymakers can use these findings to support the need to invest in childhood and young adult resources and education related to maintaining a healthy lifestyle," says Howard.

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