August 10, 2011

Sleep-Disordered Breathing In Women Could Lead To Dementia

According to a new study, older women with sleep-disordered breathing are more likely to develop cognitive impairment or dementia.

"Sleep-disordered breathing, a disorder characterized by recurrent arousals from sleep and intermittent hypoxemia, is common among older adults and affects up to 60 percent of elderly populations," the study authors wrote in the August 10 issue of JAMA.

"A number of adverse health outcomes including hypertension, cardiovascular disease, and diabetes have been associated with sleep-disordered breathing," according to background information in the article.

Cognitive impairment has also been linked to sleep-disordered breathing in some studies, but the design of most of the studies has limited the ability to draw conclusions about the relationship between the two.

"This is the first study to show that sleep apnea MAY lead to cognitive impairment," study leader Kristine Yaffe, MD, professor of psychiatry, neurology and epidemiology at University of California - San Francisco (UCSF) and chief of geriatric psychiatry at SFVAMC, said in a press release. "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 researchers studied over 10,000 women who were over the age of 65.  Those who were found to be suffering from dementia or mild cognitive impairment at the initial assessment were not included in the study.

Sleep specialists came to the study subjects' homes about four years in to the study to monitor the women as the slept.  They used special 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.

The instruments allowed researchers to track how often the women experienced apneas or hypopneas and how much time they spent in an oxygen-deprived state.

The team found about one-third of all the women developed dementia or mild cognitive impairment.  They also found that those with breathing and sleep apnea were almost twice as likely to become cognitively impaired.

About 44 percent of the women found to suffer from sleep-disordered breathing developed dementia or mild cognitive impairment, compared with 31.1 percent of those who did not have impaired breathing and sleep.

The findings were published in the August 10, 2011 issue of the Journal of the American Medical Association.


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