Older women who suffer from sleep apnea are more than twice as likely to develop dementia as those who don't, a new study shows.
According to the Journal of the American Medical Association, researchers from the University of California San Francisco studied 298 older women over the age of 65 for five years. All were free of dementia when the study began. About one-third of the women had moderate "sleep-disordered breathing," defined as 15 or more incidents per hour of sleep apnea, where breathing stops temporarily.
About one in 15 adults has at least moderate sleep apnea, according to the American Association of Oral and Maxillofacial Surgeons. Apnea is caused by airway blockages from excess tissue or other factors. When the sleeper stops breathing, oxygen levels in the blood drop. When the levels become too low, the body rouses itself and breathing begins again. Although sleepers don't wake up completely when this happens, their sleep is still interrupted. So many sufferers still feel fatigued in the morning, even if they've had a full night's rest.
The University of California researchers suggested that the amount of time that women experienced lower oxygen levels was responsible for the memory loss, not the number of interruptions or the total hours of sleep.
They also suggested that those with sleep apnea be medically followed or treated for the disorder. "Given the high prevalence of both sleep-disordered breathing and cognitive impairment among older adults, the possibility of an association between the two conditions, even a modest one, has the potential for a large public health impact," the researchers noted in their report.