Cognitive Trajectories and Subsequent Accelerometer-Measured Movement Behavior in Older Adults

Importance Previous evidence suggests a bidirectional association between physical activity and cognitive function. It remains unclear whether long-term cognitive trajectories are associated with later differences in how older adults allocate time during the day between physical activity, sedentary behavior, and sleep. Objective To assess whether long-term cognitive trajectories are associated with the subsequent amount of daily time in physical activity, sedentary behavior, and sleep. Design, Setting, and Participants This cohort study included community-dwelling adults aged 50 years or older at baseline and residing in England, using cognitive data from waves 1 (2002 to 2003) to 9 (2018 to 2019) and accelerometer data from wave 10 (2021 to 2023) of the English Longitudinal Study of Ageing. Exposures Participant-specific annual rate of change in episodic memory (assessed via immediate and delayed recall) and verbal fluency (assessed via animal naming), estimated using linear mixed-effects models. Main Outcomes and Measures The movement behavior composition, comprising mean daily minutes of moderate to vigorous physical activity, light physical activity, sedentary behavior, and sleep time. Differences were estimated in time spent in each behavior between a less favorable memory or fluency trajectory (corresponding to the 25th percentile for participant-specific memory or fluency change), median trajectory (50th percentile), and a more favorable trajectory (75th percentile). Results The study included 2529 participants (1394 [55.1%] female, 1135 [44.9%] male) with a mean (SD) baseline age of 56.1 (5.4) years. Compared with the less favorable memory trajectory, the more favorable trajectory was associated with 14 (95% CI, 8 to 21) more minutes of light physical activity and 12 (95% CI, –20 to –5) fewer minutes of sedentary behavior per day, with larger differences among participants older than 70 years (eg, 20 [95% CI, 11 to 30] more minutes light physical activity). Memory-related differences in moderate to vigorous physical activity and sleep were comparatively minor. Fluency showed similar patterns to memory, but time-use differences between trajectories were smaller. Conclusions and Relevance In this cohort study of older adults, participants with less favorable long-term memory trajectories were subsequently less active and more sedentary, suggesting that later-life activity patterns may partly reflect cognitive change.