Teen years may be critical in later stroke risk

More people have strokes and die of strokes in the southeastern area known as the stroke belt than in the rest of the United States. So far, research has shown that only part of the difference can be explained by traditional risk factors such as diabetes and high blood pressure. Previous studies have shown that people who are born in the stroke belt but no longer lived there in adulthood continue to have a higher risk of stroke, along with people who were born outside the stroke belt but lived there in adulthood.

The current study looked at how long people lived in the stroke belt and their ages when they lived there throughout life to see if any age period was most critical in influencing future stroke risk.

Data came from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study, a national random sample of the general population with more people selected from the stroke belt. The study involved 24,544 people with an average age of 65 who had never had a stroke at the start of the study, with 57 percent currently living in the stroke belt and 43 percent from the rest of the country. The study tracked each person's moves from birth to present, with some people moving into or out of the stroke belt. The participants were then followed for an average of 5.8 years. During that time, 615 people had a first stroke.

After adjusting for stroke risk factors, only living in the stroke belt during the teenage years was associated with a higher risk of stroke. People who spent their teenage years in the stroke belt were 17 percent more likely to have a stroke in later years than people who did not spend their teenage years in the stroke belt. Across all age periods, living in the stroke belt increased the risk about two-fold for African-Americans compared to Caucasians.

"This study suggests that strategies to prevent stroke need to start early in life," said study author Virginia J. Howard, PhD, of the School of Public Health, University of Alabama at Birmingham and a member of the American Academy of Neurology. "Many social and behavioral risk factors, such as smoking, are set in place during the teenage years, and teens are more exposed to external influences and gain the knowledge to challenge or reaffirm their childhood habits and lifestyle."

The study was supported by the National Institute of Neurological Disorders and Stroke and the National Institute on Aging.