Accelerometer-measured weekend catch-up sleep and incident dementia: a prospective cohort study

Objective: To investigate whether accelerometer-measured weekend catch-up sleep, defined as extending sleep on weekends to compensate for weekday sleep inadequacy, is associated with incident dementia. Design: Prospective cohort study. Setting: UK Biobank. Participants: 83,776 dementia-free adults aged 50 years or older (mean age: 63.3 years, standard deviation: 6.7 years; 56.5% female) were included at the time of seven-day wrist-worn accelerometer assessment (2013-2015), followed until December 2022 for all-cause dementia incidence. Main outcome measures: Daily sleep duration was derived from the seven-day accelerometer data using a machine learning approach. Weekend catch-up sleep was defined as the weekend-weekday difference in average sleep duration. Incident all-cause dementia was identified from linked healthcare data. Cox proportional hazard regression models was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Results: During a total of 667,928 person-years (median follow-up: 8.0 years), 713 participants developed all-cause dementia. A significant lower risk of dementia was observed among individuals with a moderate level of weekend catch-up sleep (1-1.5 hours/day). Specifically, compared with none or ≤0.5 hour, the multi-variable adjusted HRs and 95% CIs across increasing categories of weekend catch-up sleep (>0.5-1, >1-1.5, >1.5-2, and >2 hours) were 0.91 (0.74-1.11), 0.64 (0.49-0.86), 0.84 (0.60-1.16), and 0.83 (0.60-1.16), respectively. The association was stronger among participants with a weekday sleep duration <8 hours (HR: 0.49, 0.29-0.81 for >1-1.5 hours), but non-significant in those with weekday sleep durations ≥8 hours (HR: 0.72, 0.51-1.01 for >1-1.5 hours, P-interaction = 0.039). Conclusions: Moderate accelerometer-tracked weekend catch-up sleep was significantly associated with lower risk of all-cause dementia, particularly among individuals with less weekday sleep. Future studies are needed to confirm these findings and identify the optimal sleep compensation strategies for dementia prevention.