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

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 (EDS, 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 EDS 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.