The study found that African-American men who slept less than six hours a night were less likely to have a stroke when compared to African-American men who were average sleepers. The results were different for the white male population. Researchers found that white men who slept for nine or more hours a night were more likely to have a stroke when compared to white men who were average sleepers. The researchers considered average sleepers as sleeping 7 to 8.9 hours per night.
“These results suggest that short and long sleep duration may have different consequences for people depending on race and sex,” said senior study author Virginia J. Howard, Ph.D., a professor in the School of Public Health at the University of Alabama at Birmingham. “More research is needed to determine the mechanisms behind these relationships. In the meantime, this emphasizes how important it is to better monitor and control cardiovascular risk factors in middle-aged to older people who have long sleep periods.”
The study also looked at black and white women, but found that sleep duration did not play a role in stroke risk for either race.
“Previous studies had not examined relationships between sleep duration and race-sex groups,” Howard said.
The researchers analyzed nearly 17,000 black and white men and women from across the nation with an average age of 64. The participants had no history of stroke or problems with their breathing during sleep. All of the participants are part of the REGARDS (Reasons for Geographic and Racial Differences Stroke) study, a federally funded study based at UAB. They were asked how many hours of sleep they usually got on workdays and non-workdays, then they were followed for an average of six years to see who had a stroke.
In their analysis, researchers adjusted for other factors that could affect stroke risk, such as smoking status, diabetes and heart disease.
The study was funded by the National Institute of Neurological Disorders and Stroke, which is part of the National Institutes of Health. The lead author was Megan E. Petrov, Ph.D., Arizona State University. Other authors include George Howard, DrPH, University of Alabama at Birmingham; Michael A. Grandner, Ph.D., University of Arizona, Tucson; and Dawn Kleindorfer, M.D., and Jennifer R. Molano, M.D., University of Cincinnati.