Americans who grew up in the swath of the South known as the Stroke Belt are more likely to develop thinking declines later in life, even if they moved away as adults, a new study suggests.
But people who grew up elsewhere and moved to the Stroke Belt are less likely to succumb to so-called cognitive decline than if they'd lived there all their lives, researchers found.
"As other studies are also finding, this study suggests that attention should be paid to starting earlier in life to manage, or better yet prevent, risk factors for cognitive decline, and not wait until you are in your 'golden years,'" said lead researcher Virginia Howard. She's a professor of epidemiology at the University of Alabama at Birmingham School of Public Health.
The Stroke Belt includes eight states with high stroke rates, namely Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee.
In these states, the rates of obesity, smoking and high blood pressure tend to be higher than in other areas of the country, which might account for the greater risk for stroke and later thinking declines, Howard said.
Many of the factors that drain brain health are similar to those that raise the risk for stroke and heart disease, she explained.
For the study, Howard's team collected data on nearly 11,500 people, average age 64, living in the Stroke Belt, and almost 9,000 similar people not living in the Stroke Belt.
None of the participants had a stroke or mental impairment when they entered the study. Screening tests were repeated annually over nine years.
The researchers found that people who spent their childhood outside the Stroke Belt were 24% less likely to develop thinking declines.
Also, people who spent some of their childhood elsewhere were 18% less likely to develop mental impairments.
Those who lived outside the Stroke Belt as young adults were 30% less likely to develop thinking impairments.
And people who spent some of their early adulthood elsewhere were 14% less likely to show declines in thinking.
Among people who grew up in the Stroke Belt but moved away, the researchers found that those who lived all their young adulthood in the region were 51% more likely to develop mental impairment, compared to people who never lived in the Stroke Belt.
No difference in risk was seen among people who spent all or part of their childhood or some of their young adulthood in the Stroke Belt, the researchers found.
"These findings suggest that childhood or early adult residence in the Stroke Belt may increase the risk of cognitive impairment in later life," Howard said. "More research is needed to examine the characteristics of early life in the Stroke Belt that contribute to later-life cognitive impairment."
Dr. Larry Goldstein, chairman of the department of neurology at the University of Kentucky in Lexington, said that socioeconomic deprivation in the Stroke Belt might explain these findings.
"Although the study cannot determine whether the association is causal, such a relationship is plausible," he said.
There is a disproportionately higher frequency of stroke and cardiovascular risk factors, socioeconomic disparities and other stressors in the Stroke Belt region, Goldstein said.
"One could speculate that exposure to these stressors during vulnerable periods could explain the findings," Goldstein said.
The findings were to be presented next Wednesday at the American Stroke Association's International Stroke Conference, in Los Angeles. Such research is considered preliminary until published in a peer-reviewed journal.
For more on thinking declines, head to the U.S. National Institute on Aging.