Sleep-wake disturbances in sedentary community-dwelling elderly adults with functional limitations.

OBJECTIVES To evaluate sleep-wake disturbances in sedentary community-dwelling elderly adults with functional limitations. DESIGN Cross-sectional. SETTING Lifestyle Interventions and Independence in Elder (LIFE) Study. PARTICIPANTS Community-dwelling persons (mean age 78.9) who spent fewer than 20 min/wk in the previous month engaged in regular physical activity and fewer than 125 min/wk of moderate physical activity, and had a Short Physical Performance Battery (SPPB) score of <10 (N = 1,635). MEASUREMENTS Mobility was evaluated according to 400-m walk time (slow gait speed defined as <0.8 m/s) and SPPB score (≤ 7 defined moderate to severe mobility impairment). Physical inactivity was defined according to sedentary time, as a percentage of accelerometry wear time with activity of <100 counts/min; participants in the top quartile of sedentary time were classified as having a high sedentary time. Sleep-wake disturbances were evaluated using the Insomnia Severity Index (ISI) (range 0-28; ≥ 8 defined insomnia), Epworth Sleepiness Scale (ESS) (range 0-24; ≥ 10 defined daytime drowsiness), Pittsburgh Sleep Quality Index (PSQI) (range 0-21; >5 defined poor sleep quality), and Berlin Questionnaire (high risk of sleep apnea). RESULTS Prevalence rates were 43.5% for slow gait speed and 44.7% for moderate to severe mobility impairment, with 77.0% of accelerometry wear time spent as sedentary time. Prevalence rates were 33.0% for insomnia, 18.1% for daytime drowsiness, 47.8% for poor sleep quality, and 32.9% for high risk of sleep apnea. Participants with insomnia had a mean ISI score of 12.1, those with daytime drowsiness had a mean ESS score of 12.5, and those with poor sleep quality had a mean PSQI score of 9.2. In adjusted models, measures of mobility and physical inactivity were generally not associated with sleep-wake disturbances, using continuous or categorical variables. CONCLUSION In a large sample of sedentary community-dwelling elderly adults with functional limitations, sleep-wake disturbances were prevalent but only mildly severe and were generally not associated with mobility impairment or physical inactivity.