Obstructive sleep apnea (OSA) is associated with an increased risk of stroke in middle-aged and older adults, especially men, according to new results from new research supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. Overall, sleep apnea more than doubles the risk of stroke in men.
The research was reported online ahead of the print edition of the American Journal of Respiratory and Critical Care Medicine.
Obstructive sleep apnea is a common disorder in which the upper airway is intermittently narrowed or blocked, disrupting sleep and breathing during sleep. Stroke is the second-leading cause of death worldwide.
The Sleep Heart Health Study (SHHS) is a prospective, multi-center study. Researchers studied stroke risk in 5,422 participants aged 40 years and older without a history of stroke. At the start of the study, participants performed a standard at-home sleep test, which determined whether they had sleep apnea and, if so, the severity of the sleep apnea. Participants were followed for an average of nine years. During that period, a total of 193 participants had a stroke—85 men (of 2,462 men enrolled) and 108 women (out of 2,960 enrolled).
The researchers found that the increased risk of stroke appeared in men with mild sleep apnea and rose with the severity. Men with moderate to severe sleep apnea were nearly three times more likely to have a stroke than men without sleep apnea or with mild sleep apnea. However, in women, the increased risk of stroke was significant only with severe levels of sleep apnea. The increased risk of stroke from sleep apnea is independent of other risk factors such as weight, high blood pressure, race, smoking, and diabetes.
The researchers suggest that the differences between men and women might be because men are more likely to develop sleep apnea at younger ages. Therefore, they tend to have untreated sleep apnea for longer periods of time than women. “It’s possible that the stroke risk is related to cumulative effects of sleep apnea adversely influencing health over many years,” noted Susan Redline, MD, MPH, professor of medicine, pediatrics, and epidemiology and biostatistics, at Case Western Reserve University in Cleveland and lead author of the paper.
