NEW YORK CITY, NY — Compared with healthy sleep patterns, long and short sleep durations appear to almost double the likelihood of stroke in middle-aged individuals with hypertension, new research suggests.
A cohort study of 200,000 hypertensive patients, presented here at the American Society of Hypertension (ASH) 2015 Annual Scientific Meeting, showed an adjusted odds ratio (OR) of 1.83 (95% CI 1.56–2.14) for stroke in the participants who slept less than 5 hours a night on average vs those who slept 7 to 8 hours a night. In addition, the OR for stroke was 1.74 (95% CI 1.68–1.80) for those who averaged more than 8 hours of sleep per night.
"This was a bit of a surprise that this was U-shaped, but it was even more surprising to us that the risk for stroke was so big among the insufficient sleepers," lead author Dr Oluwaseun Akinseye (Icahn School of Medicine at Mount Sinai, NY) told heartwire from Medscape.
He added that, based on the findings, clinicians should consider asking about sleep history during routine examinations.
"We need to start engaging with patients about this. Although sometimes lifestyle choices might not be completely controllable, everyone should strive to get the normal, recommended sleep amount," said Akinseye.
The investigators examined data from the 2004–2013 National Health Interview Survey, conducted by the Center for Disease Control and Prevention's National Center for Health Statistics, for 203,794 adults (50% women; mean age, 59.5 years) who self-reported their hypertensive status and estimated length of time sleep status. Of these, 78.6% were white and 15.4% were black.
A total of 55.9% of the participants were in the healthy-sleepers group (7–8 hours per night), 28.7% were considered short sleepers (5–6 hours), 11.5% were long sleepers (>8 hours), and 3.9% were insufficient sleepers (<5 hours).
"Self-reported long sleepers tended to be older and female," reported Akinseye. "Insufficient sleepers tended to be middle-aged, black, or current smokers," he added. Both the long- and insufficient-sleep groups had significantly more cases of CHD (17.2% and 16.7%, respectively) vs the short- and healthy-sleep groups (11.7% and 11.1%, respectively; P<0.01).
"We wanted to at least look at CHD in this study because those with coronary heart disease tend to report abnormal sleep," Akinseye noted.
The adjusted prevalence of stroke was 11.2% in the group of insufficient sleepers vs a prevalence of 5.4% in the healthy sleepers (P<0.05). The short sleepers nearly mirrored the healthy sleepers, with a stroke prevalence of 5.7%. However, there was a much higher 13.6% prevalence in the long sleepers (P<0.05 vs healthy sleepers).
Which Came First?
"Because it was a cross-section analysis, we could not determine the cause and effects. So there is need for more longitudinal studies to actually be able to determine the direction of this association," Akinseye told heartwire .
This topic came up during the postpresentation question-and-answer session, when panel member Dr William C Cushman (Veterans Affairs Medical Center, Memphis, TN) asked which the investigators think came first. "Which is the chicken and which is the egg?"
"There's an ongoing debate about the direction of this association. And unfortunately, we weren't able to answer that at this time," Akinseye answered. "But given the possible mechanism of insufficient sleep duration increasing inflammatory markers and cardiovascular factors, we tend to think sleep is a risk factor and not the other way around. Future epidemiological studies should provide more answers."
Other panel and audience members noted during the session that they would have liked to have seen whether hypertension differed among the sleep-duration categories, how sleep patterns may have affected other CV events, if there was any effect specifically from those reporting shift work, and if the association between stroke and sleep duration holds up in nonhypertensive patients.
"I think it would strengthen a paper like this to show both types of patients," said Cushman.
The study was funded by the National Institutes of Health. Akinseye reports no relevant financial disclosures.
Heartwire from Medscape © 2015 Medscape, LLC
Cite this: Too Much/Too Little Sleep Ups Stroke Risk Nearly Twofold in Hypertensive Patients, Says NIH-Funded Study - Medscape - May 19, 2015.