Trajectories of leisure-time physical activity and subjective cognitive decline

Abstract Background This study investigates trajectories of leisure-time physical activity (LTPA) among ageing people and their associations with subjective cognitive decline (SCD). The study seeks to explore whether these trajectories vary by occupational class. Methods We used survey data from the Helsinki Health Study, a cohort of the City of Helsinki employees (N = 8960, 80% women; 2000-2022). LTPA was quantified as weekly metabolic equivalent hours (MET-h) and the change (2000-2022) was categorized as: repeated high (63%), increasing (13%), decreasing (14%), or repeated low (10%). The low LTPA cut-off (<14 MET-h/week) followed physical activity guidelines. SCD in 2022 was assessed using three validated items (memory, learning, and concentration), classified as Declined (31%, 48%, 31%) or Good (69%, 52%, 69%). Occupational class (2000-2002) was Low (routine non-manual and manual employees) or High (managers, professionals and semi-professionals). Logistic regression estimated odds ratios (ORs) with 95% confidence intervals (CIs). Results Compared to repeated high LTPA group, especially repeated low (memory: OR = 1.64, 95% CI: 1.35-1.97; learning: OR = 1.79; 95% CI: 1.49-2.16; concentration: OR = 1.93; 95% CI: 1.60-2.32) and decreasing LTPA (memory: OR = 1.72; 95% CI: 1.46-2.03; learning: OR = 1.65; 95% CI: 1.41-1.94; concentration: OR = 2.16; 95% CI: 1.84-2.53) were linked to greater SCD risk. LTPA decrease was more strongly associated with impaired learning in the low (OR = 1.91) vs. high (OR = 1.31) occupational class (interaction p = 0.0199). Conclusions Low or declining LTPA is linked to higher risk of SCD. Findings highlight the importance of maintaining consistently high physical activity to support cognitive health, particularly among socially disadvantaged groups. Key messages • Higher physical activity levels are associated with better subjective cognitive function. • Results highlight the potential value of promoting physical activity among less active individuals.