Older women with a nighttime breathing problem called sleep apnea may be at increased risk for memory lapses and other forms of cognitive impairment, especially if they carry a gene linked with Alzheimer’s disease.
Sleep apnea involves repeated pauses in breathing during sleep. Both sleep apnea and cognitive impairment are common among older adults, and a genetic variation called the APOE e4 allele is a known risk factor for both conditions, says Adam Spira, a postdoctoral fellow at the University of California in San Francisco.
Spira and his colleagues studied 448 older women (average age 83) and found that sleep apnea was associated with cognitive impairment as measured by the Mini-Mental State Examination, a questionnaire that tests orientation, memory, language, arithmetic and other mental skills. Depending on how sleep apnea was measured, women with the condition were up to three times more likely to have a low score on the test.
Among women with the APOE e4 allele, sleep apnea was even more strongly associated with cognitive impairment. But the relationship was weak among women who did not have this genetic variation.
Spira says the findings indicate sleep apnea may be a risk factor for cognitive impairment in older women, particularly in those with the APOE e4 allele, but the study does not prove a cause-and-effect relationship.