Elderly people with severe sleep apnea have more than two times the risk of ischemic stroke than elderly people with no or mild apnea, according to research reported in Stroke: Journal of the American Heart Association.
"This study provides more evidence that severe sleep apnea represents an independent risk factor for stroke in the elderly population," said Roberto Muqoz, M.D., lead author of the study.
Sleep apnea is characterized by episodes of breathing stoppages during sleep. Earlier studies of stroke and sleep apnea focused on middle-aged people, but the greatest incidence of stroke is in older people, said Muqoz, a neurologist at the Hospital de Navarra in Pamplona, Spain.
Severe sleep apnea is emerging as an important risk marker for ischemic stroke, which is caused by a blood clot that blocks blood flow to a part of the brain.
Researchers used data from 394 people, 70 to 100 years old (average age 77, 57 percent male), who participated in the Vitoria Sleep Project in Vitoria, Spain, a small town in northern Spain. The project involved interviewing participants to gather basic information such as height, weight, body mass index, neck circumference and medications for hypertension, diabetes and cholesterol. Researchers then monitored patients' breathing patterns overnight in a sleep study.
Researchers tracked medical events in the patients for six years, registering 20 ischemic strokes.
People who suffered a stroke were more likely to be male and have more severe sleep apnea, researchers found. Patients with severe sleep apnea had a two-and-a-half times greater risk of suffering a stroke during the study than patients with no apnea, mild apnea or moderate apnea, Muqoz said.