Risk may stem from cumulative effect over many years, study suggests
THURSDAY, April 8 (HealthDay News) -- The nighttime breathing disorder known as obstructive sleep apnea more than doubles the risk for stroke in men who are middle age and beyond, new research has found.
U.S. researchers looked at more than 5,400 people, age 40 and older and with no history of stroke, who were participating in the Sleep Heart Health Study. The participants underwent a standard at-home sleep test at the start of the study to determine if they had sleep apnea and, if so, the severity of the condition.
During the next nine years, 193 participants had a stroke -- 85 of the 2,462 men and 108 of the 2,960 women. A greater risk for stroke was noted in men with mild sleep apnea, rising with the severity of the apnea. Men with moderate to severe sleep apnea were nearly three times more likely to suffer a stroke than were those without sleep apnea or with mild sleep apnea.
In women, only severe levels of apnea were associated with increased risk for stroke.
The difference found between men and women may be because men are more likely to develop sleep apnea at a younger age, which means they tend to have untreated apnea for a longer time, the researchers explained.
"It's possible that the stroke risk is related to cumulative effects of sleep apnea adversely influencing health over many years," the study's lead author, Dr. Susan Redline, a professor of medicine, pediatrics, epidemiology and biostatistics at Case Western Reserve University in Cleveland, said in a news release from the American Thoracic Society.
The findings were released online April 8 in the American Journal of Respiratory and Critical Care Medicine.
"Our findings provide compelling evidence that obstructive sleep apnea is a risk factor for stroke, especially in men," Redline said. "Overall, the increased risk of stroke in men with sleep apnea is comparable to adding 10 years to a man's age. Importantly, we found that increased stroke risk in men occurs even with relatively mild levels of sleep apnea."
The next step is to determine if treating sleep apnea reduces the risk for stroke and other cardiovascular diseases, she added.
The U.S. National Institute of Neurological Disorders and Stroke has more about stroke risk factors.
-- Robert Preidt
SOURCE: American Thoracic Society, news release, April 8, 2010
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