Background: Despite independent associations of rurality and sleep with cognitive function in aging adults, studies examining their interactive association are limited. We aimed to determine whether rurality impacts the sleep-cognition relationship in aging adults.
Methods: Participants (N=61) aged 50+ years completed measures of self-report sleep [Pittsburgh Sleep Quality Index (PSQI): total sleep time (TST), sleep efficiency, and total subscores] and objective cognition [Sternberg working memory task, Wisconsin Card Sorting Task, Stroop Color-Word Test (Controlled Trials and Interference scores) and Posner attention cueing task (exogenous and endogenous scores)]. Self-reported zip codes dichotomized rural/non-rural areas. Moderated regressions examined associations between rurality and self-reported sleep with cognition, controlling for age, sex, and education.
Results: In rural residents, shorter PSQI-TST (b=-144.40, p=.004) and worse PSQI-total (b=41.79, p=.01) scores were associated with worse Stroop Interference scores, while worse PSQI-total scores was associated with better exogenous attention (b=-3.27, p=.01). In non-rural residents, lower PSQI-sleep efficiency scores was associated with worse working memory (b=0.01, p=.02) and exogenous attention (b=-1.10, p=.03).
Conclusions: Findings suggest rurality-specific associations between self-reported sleep and objective cognition in mid-to-late life. Overall, patterns of results suggests that shorter sleep duration and poorer global sleep quality may be associated with worse higher-order cognitive functioning (e.g., inhibitory control) in rural aging adults, whereas poorer sleep quality may be linked to better performance on lower-order attention functioning (e.g., exogenous spatial attention). In non-rural aging adults, greater overall sleep fragmentation may broadly impact cognition. Future studies should examine urban-specific (e.g., traffic noise) and rural-specific characteristics (e.g., limited healthcare access and social support) that may play a role in the sleep/cognition relationship.
Keywords: objective cognition, older adults, rurality, self-report, sleep.