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.

These women, drawn from a larger, ongoing study examining osteoporosis in more than 10,000 women over 65, were first examined at clinics in Pittsburgh and Minneapolis and given tests that assessed their mental and cognitive abilities. Those who were found to be suffering from dementia or mild cognitive impairment at the initial assessment weren't included in the study.

About four years later, sleep specialists came to the study subjects' homes and monitored the women as they slept using specialized equipment that measured brain activity, heart rhythm, leg movements, airflow, breathing activity in their chest and abdomen and the oxygen content of blood as it passed through their fingers.

These instruments allowed researchers to track how often the women experienced apneas (the complete blockage or airflow) or hypopneas (a reduction of airflow of 30 percent or more) and how much time they spent in an oxygen-deprived state.

About five years after their first visit, the women returned to the clinics and were given a larger battery of tests that measured their cognitive abilities, memory and verbal fluency. The tests included the Mini-Mental State Examination, the California Learning Verbal Test and a test of executive function called Trails B.

Women whose test results suggested they had dementia or mild cognitive impairment had their records reviewed by a panel of clinical experts who decided whether to confirm the diagnosis.

When Yaffe and her colleagues tabulated the results of the study, they found that about one third (35.2 percent) of all the women developed dementia or mild cognitive impairment. They also found that those with sleep apnea were almost twice as likely to become cognitively impaired.

Among the women found to suffer from sleep-disordered breathing, 44.8 percent of them developed dementia or mild cognitive impairment, compared with 31.1 percent of those who didn't have impaired breathing and sleep.

The findings suggest that the key factor leading to diminished cognition was oxygen deprivation, also called hypoxia. Women who had frequent episodes of low oxygen or spent a large portion of their sleep time in a state of hypoxia were more likely to develop cognitive impairment. By contrast, no independent connection was seen between dementia and the number of times patients were awakened in their struggle to breathe.

Some previous studies have suggested that providing oxygen therapy to patients with Alzheimer's disease and sleep apnea slows their cognitive decline. The new findings suggest that providing oxygen therapy to elderly people with sleep apnea may reduce the chances of them becoming cognitively impaired or delay the onset of mental decline.

Co-authors of the article are Alison M Laffan, Stephanie Litwack Harrison, Susan Redline, Adam P Spira, Kristine E Ensrud, Sonia Ancoli-Israel, and Katie L Stone and appears in the Journal of the American Medical Association.

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.

I am a rookie hose head going on 6 months now. Anyone who has been diagnosed with Sleep apnea and has seen improvement after treatment KNOWs that cognition is directly effected.

You wake yourself up 100-300 times a night and suffocate yourself for half the night and tell me that it doesnt effect the way you think.

Does anybody know if CPAPs have a real, clinically documented positive impact on health? Do they delay Alzheimers-related dementia? Do they reduce deaths from heart attacks? Do they produce measurable improvements in -— anything?

I’ve been on a CPAP machine for a bit more than a year and have to say that it has helped me greatly, at least sleep-wise. For the first time in probably 15-20 years, I can sleep on my back and through the night. I do feel more rested, too.

It took me a few tries to find the appropriate headgear for me, and I had to train myself to sleep with my tongue on the roof of my mouth, but it’s worth it. As silly as I probably look in the apparatus, it is worth doing.

There is a new dental device now that is replacing the use of CPAPs in many cases. It is like a retainer that fits over your bottom teeth and it has a tongue depresser attached/molded into it. In many cases, just keeping the tongue down and from falling back into the throat during sleep, will take care of most of the snoring and apnea issues. I recently got one of these from my dentist. They are very expensive and a real challenge to get accustomed to, but they really work well.

My BIL and his ENTIRE family, including the spouses of his children, have CPAP machines. I’m talking 11 people here. Reckon what the odds are that every one of them suffered from sleep apnea?

Welcome in rookie. I’m over 15 years (30,000 hours) on CPAP. My original diagnosis showed 254 waking events in my 8 hour test. There is no doubt that being diagnosed and treated saved my life and probably the lives of other people. There were just too many times when I found myself sitting beside the road, car running and in gear, two hours after I left work with no idea how I got there or when to think otherwise.

I had no idea what was wrong with me. I had been being treated for the migraines for five years and just lucked out to have a nurse that recognized the symptoms during an acupuncture treatment and recommended a sleep study.

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