Moderate to Severe Sleep Apnea Triples Stroke Risk in Men, Study Finds
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The finding comes from a major study of 5,422 people aged 40 and older who had no history of stroke. Researchers say increased risk of stroke appeared in men with mild sleep apnea and rose with severity.
Men with moderate to severe sleep apnea were about three times more likely to have a stroke than men with mild or no sleep apnea, researchers say.
The increased risk of stroke in women with obstructive sleep apnea was significant only in cases of severe apnea, according to the study, published in the American Journal of Respiratory and Critical Care Medicine.
Obstructive Sleep Apnea and Stroke
Data were taken from the Sleep Heart Health Study, which is ongoing at a number of locations. The participants in the beginning performed a standard at-home sleep test to determine whether they had sleep apnea, and if so, its severity.
They were followed for about nine years, and during that time, 193 suffered strokes -- 85 men out of 2,462 enrolled and 108 women out of 2,960.
"Although more women had strokes, relatively more men with sleep apnea than without sleep apnea had strokes, and less so in women," study author Susan Redline, MD, MPH, of Case Western Reserve University in Cleveland, tells WebMD in an email. "I think that the relatively greater impact of sleep apnea on risk of stroke in men relates to the likely longer duration of sleep apnea in men than women."
Researchers say more than 15 million strokes occur worldwide every year, and that about a third are fatal. Increased risk of stroke in people with sleep apnea exists even without other risk factors, such as weight, high blood pressure, race, diabetes, and smoking.
Men may be more at risk because they develop sleep apnea at younger ages, the researchers say, and thus go untreated for longer periods.
Sleep Apnea Linked to Heart Disease, Diabetes Too
Michael J. Twery, PhD, director of the National Heart, Lung and Blood Institute at the National Institutes of Health, says in the news release that research on effects of sleep apnea is important to gain increased understanding of how sleep affects health.
Such research, he says, can also provide insight into how cardiovascular problems like strokes and high blood pressure develop.
Untreated sleep apnea has also been linked to obesity and diabetes, unusual daytime sleepiness, and increased risk of injuries and death due to drowsy driving or other mishaps.
Redline describes the findings as "compelling" and says the risk of stroke in men with sleep apnea is significant and that discovery of the disorder could add years to their lives.
She says the next logical step for researchers is to study whether treating sleep apnea can reduce a person's risks that could hurt health or result in death.
The importance of diagnosing and treating sleep apnea ought to be stressed more in medical circles because it is still under-recognized by physicians, says John Heffner, MD, past president of the American Thoracic Society.
SOURCES: News release, American Journal of Respiratory and Critical Care
Redline, S. American Journal of Respiratory and Critical Care Medicine, April 2010.
Susan Redline, MD, MPH, professor of medicine, pediatrics and epidemiology and biostatistics, Case Western Reserve University, Cleveland.
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