Sleep apnea tied to later dementia
Elderly women with nighttime gaps in breathing prone to cognitive problems
By Nathan Seppa
Breathing irregularities that rob the brain of oxygen during sleep may imperil a person’s ability to think straight. A study of women 65 and older finds that those with seriously disordered breathing have an increased risk of developing mild cognitive impairment or dementia in subsequent years, researchers report in the Aug. 10 Journal of the American Medical Association.
Individuals with disordered breathing slow down or stop taking breaths during sleep and often must gasp to catch up. The condition includes sleep apnea, an abnormal pattern that deprives the brain of oxygen and intermittently interrupts the deep sleep needed for satisfying rest.
Earlier, short-term studies linked disordered breathing to cognitive impairment, citing hypoxia, a lack of oxygen, as a culprit. But long-term data have been lacking.
In the new study, physician Kristine Yaffe of the University of California, San Francisco, and her colleagues tested 298 women, average age 82, from 2002 to 2004 for sleep problems, monitoring each individual overnight and noting any stoppages of air flow in their breathing as well as arousals from sleep. About one-third of the patients had disordered breathing. None of these women was cognitively impaired at the time of the sleep test. After the test, patients were given their scores and told if they showed signs of severe sleep problems, says study coauthor Katie Stone, an epidemiologist at the California Pacific Medical Center in San Francisco. Whether they sought treatment is unknown, she says.
When researchers repeated standard cognition tests on the women roughly five years later, 45 percent of those who had disordered breathing had developed dementia or milder cognitive impairments, compared with 31 percent of those with no breathing irregularities.