Sleep apnea linked to increased risk of dementia in elderly women
Elderly women who suffer from sleep apnea -- characterized by disrupted breathing and sleep and a reduction in the intake of oxygen -- are about twice as likely to develop dementia in the next five years as those without the condition, according to a multi-center study led by researchers from the University of California, San Francisco.
The findings , published in the August 10, 2011 issue of the Journal of the American Medical Association , showed for the first time what sleep specialists have long suspected but hadn't proved: that sleep apnea, also known as sleep-disordered breathing, can deprive the brain and other organs of the oxygen they need and, may, over time, trigger declines in cognitive ability.
"This is the first study to show that sleep apnea MAY lead to cognitive impairment," said study leader Kristine Yaffe, MD, professor of psychiatry, neurology and epidemiology at UCSF and chief of geriatric psychiatry at SFVAMC. "It suggests that there is a biological connection between sleep and cognition and also suggests that treatment of sleep apnea might help prevent or delay the onset of dementia in older adults."
"While we cannot conclude from these results that SDB causes cognitive impairment, our study suggests that it may at least be a contributing factor," said Yaffe.
The senior author of the study is Katie Stone, PhD, of the California Pacific Medical Center Research Institute.
In people with sleep apnea, the airways leading from the lungs to the nose and mouth collapse as the individuals sleep, interfering with the ability to inhale. People with sleep apnea usually snore, sometimes loudly, and are wakened many times a night for tiny fragments of time as they gasp for air.
While previous research had found an association between sleep apnea and dementia, those studies weren't structured to follow the impact of sleep apnea on people who had normal cognitive abilities at the onset. The strength of the new findings comes from the fact that the 298 subjects began the study without dementia or measurable cognitive impairments, allowing researchers to measure the relationship between sleep apnea and mental acuity.