Relationship between development trajectories of leisure activity and sleep time on incident cognitive impairment: A study based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS)

Background Leisure activity and sleep time are key factors in cognitive impairment, but the impact of their long-term trajectories on incident cognitive impairment remains unclear. Objective To examine the association of leisure activity trajectories, sleep time trajectories and their combined effects with incident cognitive impairment in older adults. Methods Data from the Chinese Longitudinal Healthy Longevity Survey (2008-2018) were analyzed, including adults aged >= 65 who participated in at least three surveys. Group-based trajectory modeling explored leisure activity and sleep time patterns. Cox proportional-hazards regression model assessed the association of leisure activity trajectories and sleep time trajectories and their combined effects with incident cognitive impairment. Results We included 3094 participants with a median follow-up of 6.07 years. The optimal trajectory groups for leisure activity and sleep time were four and three, respectively. The low-level leisure activity group were associated with an increased risk of cognitive impairment (HR, 95%CI: 2.07, 1.37-3.13), whereas the high-level leisure activity group were associated with a reduced risk of cognitive impairment (HR, 95%CI: 0.60, 0.36-0.99). Short sleep time group was associated with a reduced risk of cognitive impairment (HR, 95%CI: 0.62, 0.41-0.92). In the combined effect, leisure activity belonging to the low-level group and sleep time belonging to the moderate sleep time group or the long sleep time group were associated with an increased risk of cognitive impairment. Conclusions Long-term high-level leisure activity and short sleep time are associated with a reduced risk of cognitive impairment in older adults.