Objectives: To determine the prevalence of self-reported napping and its association with subjective nighttime sleep duration and quality, as measured according to sleep-onset latency and sleep efficiency.
Design: Cross-sectional study.
Setting: Lifestyle Interventions and Independence for Elders Pilot Study.
Participants: Community-dwelling older adults (N=414) aged 70 to 89.
Measurements: Self-report questionnaire on napping and sleep derived from the Pittsburgh Sleep Quality Index (PSQI) scale.
Results: Fifty-four percent of participants reported napping, with mean nap duration of 55.0+/-41.2 minutes. Nappers were more likely to be male (37.3% vs 23.8%, P=.003) and African American (20.4% vs 14.4%, P=.06) and to have diabetes mellitus (28% vs 14.3%, P=.007) than non-nappers. Nappers and non-nappers had similar nighttime sleep duration and quality, but nappers spent approximately 10% of their 24-hour sleep occupied in napping. In a multivariate model, the odds of napping were higher for subjects with diabetes mellitus (odds ratio (OR)=1.9, 95% confidence interval (CI)=1.2-3.0) and men (OR=1.9, 95% CI=1.2-3.0). In nappers, diabetes mellitus (beta=12.3 minutes, P=.005), male sex (beta=9.0 minutes, P=.04), higher body mass index (beta=0.8 minutes, P=.02), and lower Mini-Mental State Examination score (beta=2.2 minutes, P=.03) were independently associated with longer nap duration.
Conclusion: Napping was a common practice in community-dwelling older adults and did not detract from nighttime sleep duration or quality. Given its high prevalence and association with diabetes mellitus, napping behavior should be assessed as part of sleep behavior in future research and in clinical practice.