Key points are not available for this paper at this time.
Abstract Introduction Poor sleep health is a proposed risk factor for Alzheimer’s disease (AD). Despite known sex differences in AD prevalence (higher in women), whether sex impacts associations between objective sleep parameters and specific cognitive functions remains underexplored. Such investigations are warranted and will provide information regarding potential sex-specific targets for early intervention and/or markers of AD risk. This study tested whether sex moderates associations between polysomnographic assessed sleep and cognition in older adults. Methods Older adults (Mage=68.2±5.5; 44 women/29 men) completed overnight polysomnography (Sleep Profiler) and cognitive tasks NIH Toolbox: Pattern Comparison (processing speed), Oral Symbol Digit Test (attention and processing speed), List Sorting (working memory), Auditory Verbal Memory Task (episodic memory), Flanker (inhibition), Dimensional Change Card Sort (cognitive flexibility). Multiple regressions examined whether sleep metrics (sleep onset latency, wake time after sleep onset, sleep efficiency, total sleep time), macro-architecture (%N1-N3, %REM) or micro-architecture (sleep spindle duration and index) interacted with biological sex in associations with cognition, controlling for age, education and apnea-hypopnea index. Results Sleep onset latency (R-squared=.06, p=.03) and sleep spindle duration (R-squared=.05, p=.05) interacted with sex in their associations with cognitive flexibility. Specifically, in women (not men), longer sleep onset latency (B=-.01, SE=.002, p=.03) and longer spindle duration (B=-.08, SE=.03, p = .005) were associated with worse cognitive flexibility. Conclusion The link between polysomnographic sleep and cognitive flexibility in older adults may be sex dependent. Sleep onset latency cognitive (rumination/worry) and neural (physiological arousal/pre-frontal activation) mechanisms may interact with female sex-steroid alterations (post-menopausal drops in circulating estrogen and progesterone) and exacerbate its negative impact on cognitive flexibility. We also speculate that longer sleep spindle duration in the presence of dysfunctional cognitive flexibility may reflect compensatory thalamo-prefrontal cortical regulation (greater need for nighttime cognitive/cortical arousal reduction) that is further influenced by prefrontal sex-steroid mechanisms. Longitudinal studies in larger samples of cognitively healthy and impaired older adults are needed to further understand whether polysomnographic sleep metrics represent sex-specific markers of future cognitive decline. Support (if any) This research was made possible by awards (PI:Curtis) from the American Academy of Sleep Medicine Foundation, a foundation of the American Academy of Sleep Medicine.
Curtis et al. (Sat,) studied this question.