"This study provides more evidence that severe sleep apnea represents an independent risk factor for stroke in the elderly population," said Roberto Muñoz, 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 Muñoz, 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, Muñoz said.
"Sleep apnea is two to three times more common in the elderly compared to middle-aged people. However, typical symptoms of sleep apnea, such as loud snoring or excessive daytime sleepiness, are less prevalent in the elderly compared to middle-aged people. We should be aware of these symptoms, and specifically look for the presence of repetitive breathing pauses in our patients and relatives," Muñoz said.
Researchers suggest apnea treatment be started if doctors find a high rate of episodes of decreased breathing or breathing interruption, particularly in patients with other cardiovascular risk factors.
"Snoring is the most important warning sign for sleep apnea," Muñoz said. "People who live alone, which is common in the elderly, should be aware that excessive daytime sleepiness is another key risk factor."
Co-authors are Joaquín Duran-Cantolla, M.D., Ph.D.; Eduardo Martínez-Vila, M.D., Ph.D.; Jaime Gallego, M.D., Ph.D.; Ramón Rubio, M.D., Ph.D.; Felipe Aizpuru, M.D., Ph.D.; and Germán De La Torre, M.D., Ph.D.
The Health Research Funds of Spanish Health Ministry, Department of Health of Basque Government, SEPAR (Sociedad Española de Neumologia y Cirugía Toracia) and Spanish Education Ministry provided grants for the study.
Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.
NR06 – 1073 (Stroke/Muñoz)
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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