(dailyRx News) Untreated sleep apnea has been linked to a long list of health risks. Now silent strokes - where the person doesn't know they had a stroke - can be added to that list.
Silent strokes are small strokes with no outward symptoms but which still cause lesions on the brain and can increase a person's risk of a major stroke in the future.
The small study was led by Dr. Jessica Kepplinger, a stroke fellow in the Dresden University Stroke Center's Department of Neurology at the University of Technology in Dresden, Germany.
Kepplinger's team investigated 56 patients, who stayed overnight in the hospital for testing of sleep apnea. Their average age was 67 and about half were women.
The researchers used MRI and computer imaging to determine whether the patients suffered from a silent stroke and whether they had the white matter lesions on the brain caused by silent strokes.
They found that 51 of the 56 patients who had a stroke also had some sleep apnea. These patients were more likely to have silent strokes and the brain lesions.
"Sleep apnea is widely unrecognized and still neglected," Kepplinger said.
"Patients who had severe sleep apnea were more likely to have silent strokes and the severity of sleep apnea increased the risk of being disabled at hospital discharge," she said.
Over a third of the patients with lesions had severe sleep apnea, and the Kepplinger's team found that having more than five sleep apnea episodes each night was associated with silent strokes.
Men were more likely to have silent strokes than women, but the link between apnea and silent strokes remained present after accounting for the gender differences in the study.
"Sleep apnea has many, many potential adverse medical consequences," said Dr. William Kohler, Director of the Florida Sleep Institute in Spring Hill, Florida.
"This study is just another important step in informing physicians and the public about the importance of properly diagnosing and treating sleep apnea," Kohler said.
Kepplinger said one limitation of the study is their "findings may not be entirely generalizable to other populations with diverse ethnicities" because all patients in this study were white.
The researchers recommended that sleep apnea should be considered as much a vascular risk factor as other known factors, such as high blood pressure.
The study was presented at the American Stroke Association's International Stroke Conference 2012. Funding information for the study was not available, but the authors stated no conflicts of interest.