Good news, perhaps, for sleepless black men
Sleep duration was tied to stroke risk differently depending on race in middle-age and older men, a prospective cohort study found.
Black men who slept less than 6 hours a night (short sleepers) were about 80% less likely to have a stroke than average sleepers, according to Megan Petrov, PhD, of Arizona State University and Phoenix and colleagues writing in Neurology.
And white men who slept slept 9 or more hours a night (long sleepers) had about a 70% higher risk of stroke than average sleepers, the researchers reported. There were no differences in stroke risk by sleep duration among black or white women.
"More research needs to be done related to understanding of the mechanisms by which shorter sleep duration conveys benefit in reducing stroke risk in black men but not other race or sex groups," study author Virginia Howard, PhD, of the University of Alabama at Birmingham, told MedPage Today. "And for persons with long sleep patterns, especially white men, more attention needs to be paid to monitoring and management of stroke risk factors."
Overall, people who sleep less tend to have increased risk for cardiovascular problems like high blood pressure, stroke, and metabolic disease, noted Virend Somers, MD, PhD, of the Mayo Clinic in Rochester, Minnesota, who was not involved with the study.
Consequently the current study's result were unexpected. "It's very surprising that they found that African-American men who slept 6 hours or less seemed to have a lower risk of stroke. This is not what one would have predicted based on the literature," Somers said in an interview with MedPage Today. "The study is very well done, yet the data don't fit with our expectations -- which is always intriguing and exciting because that means there's more to the story than we thought."
In this analysis, Petrov and co-authors evaluated 16,733 people from the REGARDS cohort age 45 and older who had no history of stroke or sleep apnea. Mean participant age was 64 and approximately 37% were black.
At baseline (from 2008 to 2010), participants were asked how many hours they usually slept on work days and non-work days. About 10% (n=1,747) were classified as short sleepers and 6.8% (n=1,134) as long sleepers. Black adults represented 60% of short sleepers and 29.7% of long sleepers.
Participants also completed the Berlin Questionnaire to capture information about snoring, daytime sleepiness, and history of high blood pressure or body mass index (BMI) of ≥30.
Over an average follow-up of 6.1 years, 460 stroke events occurred. After adjusting for stroke risk factors, short sleep duration was significantly associated with decreased risk for stroke among black participants (HR 0.49, 95% CI 0.28-0.85), especially black men (HR 0.21, 95% CI 0.07-0.69). For white men, there was a strong trend toward increased stroke risk with short sleep (HR 1.68, 95% CI 0.96-2.93).
Long sleep duration was significantly associated with increased risk for stroke among white men (HR 1.71, 95% CI 1.06-2.76) but not black men (HR 0.55, 95% CI 0.13-2.32).
"Minorities, particularly black individuals, are at risk for both short and long sleep duration, poorer sleep quality, and more irregular sleep/wake patterns," said Jessica Lunsford-Avery, PhD, of Duke University Medical Center, who was not involved in the study.
"As these same sleep problems are also related to risk for cardiometabolic events, including stroke, it is important to understand whether the mechanisms underlying sleep-cardiometabolic relationships differ among racial and ethnic groups," she told MedPage Today. "For example, if processes linking sleep and cardiometabolic health differ between racial and ethnic groups, this would argue against a 'one size fits all' prevention or treatment strategy for addressing sleep problems and associated cardiometabolic risk in different populations."
This study has several limitations: it is based on self-reports and participants reported sleep habits only once, at baseline. While the researchers adjusted for risk for snoring with Berlin Questionnaire data, they could not rule out undiagnosed sleep apnea. Also, the broad confidence intervals suggest the study was underpowered for these subgroup analyses -- there were only 172 stroke events among the cohort's black participants.
Future investigations should include repeated overnight polysomnography and wrist actigraphy sleep studies, which could help rule out other potential confounding variables like insomnia, Petrov and colleagues noted.
The study was funded by the National Institute of Neurological Disorders and Stroke. Researchers reported relationships with Fitbit, Curaegis Technologies, Natrol, Nexalin Technologies, and Kemin Industries.
Source Reference: Petrov M, et al "Sleep duration and risk of incident stroke by age, sex, and race: The REGARDS study" Neurology 2018; DOI: 10.1212/WNL.0000000000006424.
Read the original article on Medpage Today: Racial Difference Seen in Men's Sleep-Stroke Relationship