Longitudinal associations between changes in higher-level competence and sleep status among community-dwelling older adults in Japan.

Introduction: Sleep health is an important component of healthy aging, yet longitudinal evidence on whether changes in higher-level competence are associated with subsequent sleep outcomes remains limited among community-dwelling older adults in Japan. This study examined the longitudinal association between changes in higher-level competence and later sleep status, including short sleep duration and non-restorative sleep, over a 6-year period. Methods: Data were derived from the Community Empowerment and Care for Wellbeing and Healthy Longevity study conducted from 2017 to 2023 in a suburban Japanese community. Among 1,161 individuals surveyed at baseline, 450 adults aged 65 years and older who had no short sleep duration or non-restorative sleep at baseline and completed follow-up in 2023 were included in the final analysis. Higher-level competence was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence, and change scores from 2017 to 2023 were categorized as decline, stable, or improvement. Sleep outcomes at follow-up were defined as incident short sleep duration of less than 6 h per day and non-restorative sleep based on self-report. Multivariable logistic regression analyses were performed, with crude estimates and covariate-adjusted estimates reported separately. Results: Participants with a decline in higher-level competence had higher odds of short sleep duration (odds ratio, 2.51; 95% confidence interval, 1.33-4.75) and non-restorative sleep (odds ratio, 1.78; 95% confidence interval, 1.11-2.86) compared with those with stable competence, whereas improvement in higher-level competence was not significantly associated with either outcome. In subdimension analyses, decline in social role functioning was associated with short sleep duration, while declines in instrumental activities of daily living and social role functioning were associated with non-restorative sleep. Discussion: These findings suggest that deterioration in higher-level competence, particularly social role functioning, is longitudinally associated with poorer sleep status among older adults. The results should be interpreted as associations rather than causal effects, but they indicate that functional independence and social engagement may be relevant components of sleep health promotion in later life.