The COVID-19 pandemic's effects on cognition and 24-hour movement behaviours: Findings from the CLSA

Background

The COVID-19 pandemic may have negatively impacted cognition due to pandemic-associated changes in 24-h movement behaviours (i.e., physical activity, sedentary behaviour, and sleep). Whether the pandemic's effects vary by age and sex is unclear.

Methods

We examined those participants (aged 45–85 years) of the Canadian Longitudinal Study on Aging (CLSA) with complete neuropsychological measures at baseline (2011–2015), no dementia/memory disorder, and partial or complete assessments at baseline, 3-year (FU1; 2015–2018), and 6-year follow-up (FU2; 2018–2021). Participants were categorized into pre-pandemic (N = 6174) or intra-pandemic (N = 5181) cohorts by FU2 assessment timing (before/after March 11th, 2020) and stratified by baseline age/sex. Cognition was measured with reliable change indices using: the Rey Auditory-Verbal Learning Test, Mental Alternation Test (MAT), and animal fluency. We indexed physical activity and sedentary behaviour using the Physical Activity Scale for the Elderly (PASE), and self-reported restless sleep.

Findings

Compared with their pre-pandemic peers, intra-pandemic men aged 65–85 years had lower animal fluency (−0.40 points, 99 % CI: [−0.72, −0.07]), lower PASE (−16.48 points, 99 % CI: [−24.60, −8.36]) and 14 % higher probability of ≥4 h/day sedentary behaviour (99 % CI: [0.03, 0.26]) at FU2. Intra-pandemic women aged 65–85 years had lower MAT (−0.43 points, 99 % CI: [−0.86, −0.01]) and 12 % higher probability of ≥4 h/day sedentary behaviour (99 % CI: [0.01, 0.23]). There were no between-cohort differences for those aged 45–64 years. Pandemic-related changes in 24-h movement behaviours (FU1 to FU2) were not associated with cognitive changes, regardless of age or sex.

Interpretation

The pandemic's effects on cognition and 24-h movement behaviours varied by age and sex; these effects are unrelated.