Trajectories of leisure-time physical activity across occupational classes and their associations with subjective cognitive decline in relation to statutory retirement

Abstract

Dementia represents a major public health challenge due to its increasing prevalence. Limited research has explored how patterns of leisure-time physical activity (LTPA) vary across occupational classes and how these patterns are associated with cognition. This study aimed to examine (1) trajectories of LTPA in low and high occupational classes before and after statutory retirement and (2) the associations between trajectory membership and subjective cognitive decline (SCD) after retirement. We used repeated survey data from the Helsinki Health Study, a longitudinal cohort at Phase 1 focused on employees of the City of Helsinki, Finland, five Phases (2000–2022, N  = 8960). The final analytic sample included 4059 participants, with a mean age of 51.50 years at Phase 1. LTPA was quantified as weekly metabolic equivalent hours (MET-h). SCD was assessed using questions on memory, learning ability, and concentration, classified as “Poor” or “Good”. Occupational class at Phase 1 was categorized as “Low” (e.g., manual employees) or “High” (e.g., professionals). Trajectories of LTPA were identified using group-based trajectory modeling. Binomial logistic regression was used to assess the association between trajectory membership and SCD. Distinct LTPA trajectories representing patterns of LTPA levels and change over time were identified. These appeared broadly similar across low and high occupational classes. Most trajectories were stable and characterized by relatively high levels of LTPA before and after statutory retirement. A decline in the highest LTPA trajectory was found among participants with low occupational class. Results from the binomial logistic regression analyses showed that participants in lower LTPA trajectories had a higher likelihood of SCD in both classes. Notably, the lowest trajectory groups within both occupational classes were associated with poorer learning, with Average Marginal Effects (AME) of 22 percentage points [95% CI: 14–30] in low class and 18 percentage points [95% CI: 11–25] in high class. Our results highlight that higher levels of LTPA are associated with better cognitive health during the retirement transition in both low and high occupational class groups.