Sleep, Cognitive Dysfunction, and Daily Living in Chinese Older Adults

Cognitive dysfunction and impaired activities of daily living (ADL) in middle-aged and older adults are critical public health issues, but the links with sleep remain unclear. Using data from CHARLS, which involved 39,852 participants aged 45 years or older, this study explored these associations using restricted cubic spline and multivariate logistic regression models. A U-shaped relationship was found between sleep duration and cognitive performance (including information processing speed, memory, and attention) as well as the risk of ADL limitation, with 7 hours as the optimal duration. Both short (<6 h) and long (≥9 h) sleep were linked to higher cognitive decline risk (OR=1.51 and 1.72, P<0.05). Stratified analyses revealed that older males with long sleep (≥9 h) and older females with short sleep (6 to 7 h) had elevated risks of ADL limitation (OR=1.72 and 1.51, respectively). This study provides epidemiological evidence for targeted interventions.