Association of sleep characteristics and cognition in older community-dwelling men: The MrOS sleep study

Abstract

Study Objectives: To examine the association of objectively and subjectively measured sleep characteristics with cognition in older men. Design: A population-based cross-sectional study. Setting: 6 centers in the United States. Participants: 3,132 community-dwelling older men (mean age 76.4 ± 5.6 years). Interventions: None. Measurements and Results: Objectively measured sleep predictors from wrist actigraphy were total sleep time (TST), sleep efficiency (SE), and wake after sleep onset (WASO). Subjective sleep predictors were self-reported poor sleep (Pittsburgh Sleep Quality Index [PSQI] > 5), excessive daytime sleepiness (ED S, Epworth Sleepiness Scale Score > 10), and TST. Cognitive outcomes were measured with the Modified Mini-Mental State examination (3MS), the Trails B test, and the Digit Vigilance Test (DVT). After adjustment for multiple potential confounders, WASO was modestly related to poorer cognition. Compared to those with WASO < 90 min, men with WASO ≥ 90 min took 6.1 sec longer to complete the Trails B test and had a 0.9-point worse 3MS score, on average (P < 0.05). Actigraphically measured long sleepers had a slightly worse 3MS score compared to those with 7-8 h of sleep, but had similar Trails B and DVT completion times. Compared to those who self-reported sleeping 7-8 h, long sleepers (> 8 h) on average took 8.6 sec more to complete the Trails B test, had a 0.6-point worse 3MS score, and took 46 sec longer to complete the DVT (P < 0.05). PSQI and ED S were not independently related to cognitive outcomes. Conclusions: There were modest cross-sectional associations of WASO and self-reported long sleep with cognition among older community-dwelling men. EDS and PSQI were not related to cognition.