Risk of cognitive impairment affected by hypoxia, sleep apnea, but not sleep fragmentation, duration
TUESDAY, Aug. 9 (HealthDay News) -- Older women with sleep-disordered breathing have an increased risk of cognitive impairment and dementia, according to a study published in the Aug. 10 issue of the Journal of the American Medical Association.
Kristine Yaffe, M.D., from the University of California in San Francisco, and colleagues, prospectively investigated the association between sleep-disordered breathing and cognitive impairment in 298 women (mean age, 82.3 years) without dementia. Data were collected from overnight polysomnography, carried out from November 2006 to September 2008. The independent association of dementia or mild cognitive impairment with sleep-disordered breathing was assessed after adjusting for age, race, body mass index, education, smoking, presence of diabetes or hypertension, medication use (antidepressants, benzodiazepines, or nonbenzodiazepine anxiolytics), and baseline cognitive scores. Hypoxia, sleep fragmentation, and sleep duration were investigated as potential mechanisms underlying this association.
The investigators found that the 105 women (35.2 percent) with sleep-disordered breathing were more likely to develop mild cognitive impairment or dementia compared to the 193 women without sleep-disordered breathing (44.8 versus 31.1 percent; adjusted odds ratio [aOR], 1.85). The risk of mild cognitive impairment or dementia was associated with measures of disordered breathing including elevated oxygen desaturation index (aOR, 1.71) and high percentage of sleep time in apnea or hypopnea (aOR, 2.04), but the risk of cognitive impairment was independent of measures of sleep fragmentation (arousal index and wake after sleep onset) or sleep duration.
"Among older women, those with sleep-disordered breathing compared with those without sleep-disordered breathing had an increased risk of developing cognitive impairment," the authors write.
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