Featured Research

from universities, journals, and other organizations

Too Much, Too Little Sleep Increases Ischemic Risk In Postmenopausal Women

Date:
July 21, 2008
Source:
American Heart Association
Summary:
Sleeping nine hours or more a night significantly increases the risk for ischemic stroke among post menopausal women. Sleeping less than 6 hours showed a modest increase risk of stroke, but was reported by twice as many women. The findings cannot be applied to other groups.

Postmenopausal women who regularly sleep more than nine hours a night may have an increased risk of ischemic stroke, researchers reported in Stroke: Journal of the American Heart Association.

Compared to women sleeping seven hours, the risk of ischemic stroke was 60-70 percent higher for those sleeping nine hours or more, said lead author Jiu-Chiuan Chen, M.D., Sc.D., assistant professor of epidemiology at the University of North Carolina’s School of Public Health in Chapel Hill.

“After accounting for all common clinical conditions predictive of stroke, we found this increase was statistically significant: sleeping nine hours or more is strongly associated with increased risk of ischemic stroke,” he said.

Researchers also found that women who slept six hours or less were at 14 percent greater stroke risk than those who slept seven hours a night. Nearly twice as many women reported sleeping less than six hours (8.3 percent) than those who reported sleeping nine hours or more (4.6 percent).

“The prevalence in women of having long sleep duration is much lower than having sleep duration less than six hours. So the overall public health impact of short sleep is probably larger than long sleep,” Chen said. “This study provides additional evidence that habitual sleep patterns in postmenopausal women could be important for determining the risk of ischemic stroke.”

The findings apply only to postmenopausal women and cannot be applied to other groups, including men and younger women. Postmenopausal women 50- to 79-years-old may be more susceptible to the detrimental effects of sleep deprivation than others.

“Our study population is a very specific group, and the duration of sleep needed for optimal health probably differs for various population groups,” he said. “People who feel that their sleep problems are a burden to their daytime activities are encouraged to discuss their concerns with physicians who can better interpret their significance and offer advice in the context of their overall health.”

Three large previous studies have addressed the role of sleep duration in coronary artery disease and/or stroke. They yielded mixed results and didn’t account for the many factors that may increase the risk of cardiovascular disease and stroke, including: age, race, socioeconomic factors such as family income and employment, smoking, depression, exercise, hormone therapy in postmenopausal women, high-blood pressure, high cholesterol, diabetes, and obstructive sleep apnea.

Chen and his colleagues included known risk factors that might confound any apparent association of sleep duration and ischemic stroke in this analysis of data from the multi-ethnic Women’s Health Initiative Observational Study. The study’s 93,676 women were 50 to 79 years old at the time of their enrollment at 40 U.S. clinical centers. Researchers conducted the study from 1994 to 2005.

Researchers asked the women how long they typically slept each night. The results were: five hours or less, 8.3 percent; six hours, 26.9 percent; seven hours, 37.5 percent; eight hours, 22.7 percent; nine hours, 4.0 percent and 10 hours or more, 0.6 percent.

After accounting for the common risk factors for ischemic stroke, the increased relative stroke risks compared to the seven-hour-sleep group were: 14 percent for six hours or less sleep; 24 percent for eight hours of sleep; and 70 percent for nine or more hours of sleep.

Among the team’s other results:

  • Long sleep durations were associated with being retired or unemployed; smoking, being physically inactive or having cardiovascular disease, diabetes, hypertension, high cholesterol or depression.
  • Overweight women and minority women were more likely to sleep six hours or less.
  • Women with current hormone therapy were less likely to sleep six hours or less.
  • Income, physical activity, depressive symptoms and other cardiovascular risk factors correlated with sleep duration, but didn’t fully account for the link between stroke and sleep patterns.

Medical, psychosocial and lifestyle variables included in their analysis could not completely explain the increased ischemic stroke risk associated with short and long sleep among postmenopausal women. But Chen said many studies have documented physiological consequences of sleep deprivation.

“Our data do not imply that if women with long sleep cut their sleep hours they would be at a lower risk,” Chen emphasized. “At this point, we still cannot determine that long sleep causes ischemic stroke. The observed increase in stroke risk in long sleepers may be due to some unmeasured factors, such as undiagnosed sleep disorders, although we did attempt to account for that in our analysis.”

“Further studies are needed to help us understand the possible mechanisms involved in the associations found in this study,” he said, “because there are very limited neurobiological data relating long sleep to an increased risk of coronary heart disease or ischemic stroke that also is found in other large epidemiologic studies.”

Co-authors are Robert L. Brunner, Ph.D.; Hong Ren, M.S.; Sylvia Wassertheil-Smoller, Ph.D.; Joseph C. Larson, M.S.; Douglas W. Levine, Ph.D.; Matthew Allison, M.D.; Michelle J. Naughton, Ph.D. and Marcia L. Stefanick, Ph.D. Individual author disclosures can be found on the manuscript.


Story Source:

The above story is based on materials provided by American Heart Association. Note: Materials may be edited for content and length.


Cite This Page:

American Heart Association. "Too Much, Too Little Sleep Increases Ischemic Risk In Postmenopausal Women." ScienceDaily. ScienceDaily, 21 July 2008. <www.sciencedaily.com/releases/2008/07/080717160815.htm>.
American Heart Association. (2008, July 21). Too Much, Too Little Sleep Increases Ischemic Risk In Postmenopausal Women. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2008/07/080717160815.htm
American Heart Association. "Too Much, Too Little Sleep Increases Ischemic Risk In Postmenopausal Women." ScienceDaily. www.sciencedaily.com/releases/2008/07/080717160815.htm (accessed April 24, 2014).

Share This



More Health & Medicine News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Big Pharma Braces for M&A Wave

Big Pharma Braces for M&A Wave

Reuters - Business Video Online (Apr. 22, 2014) Big pharma on the move as Novartis boss, Joe Jimenez, tells Reuters about plans to transform his company via an asset exchange with GSK, and Astra Zeneca shares surge on speculation that Pfizer is looking for a takeover. Joanna Partridge reports. Video provided by Reuters
Powered by NewsLook.com
Study Says Most Crime Not Linked To Mental Illness

Study Says Most Crime Not Linked To Mental Illness

Newsy (Apr. 22, 2014) A new study finds most crimes committed by people with mental illness are not caused by symptoms of their illness or disorder. Video provided by Newsy
Powered by NewsLook.com
Hagel Gets Preview of New High-Tech Projects

Hagel Gets Preview of New High-Tech Projects

AP (Apr. 22, 2014) Defense Secretary Chuck Hagel is given hands-on demonstrations Tuesday of some of the newest research from DARPA _ the military's Defense Advanced Research Projects Agency program. (April 22) Video provided by AP
Powered by NewsLook.com
How Smaller Plates And Cutlery Could Make You Feel Fuller

How Smaller Plates And Cutlery Could Make You Feel Fuller

Newsy (Apr. 22, 2014) NBC's "Today" conducted an experiment to see if changing the size of plates and utensils affects the amount individuals eat. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins