Data-driven leisure-time physical activity trajectories of over 46 years and their associations with cognition in nonagenarians: a cohort study

OBJECTIVES: In short follow-up studies, greater leisure-time physical activity (LTPA) has been associated with better cognition in old age, but more longitudinal studies are needed. Our aim was to identify long-term LTPA trajectories from midlife to late old age and examine whether these trajectories are associated with nonagenarians' cognition. METHODS: In total, 125 participants from the NONAGINTA-Memory and Health in Nonagenarians study were included. The participants responded to health surveys of the older Finnish Twin Cohort study, including LTPA at the mean ages of 45, 52, 59, and 91 years. Cognition was assessed at the mean age of 91 years (standard deviation 1.54) via telephone interview (global cognitive function, episodic memory, and semantic fluency). We identified LTPA trajectories with K-means clustering for longitudinal data, and we used generalized estimating equations models to investigate differences in cognition among the LTPA trajectories. Covariates included age, sex, and education. RESULTS: We found 3 LTPA trajectories from midlife to nonagenarian age. The largest proportion of participants belonged to the Constant low trajectory (52%), characterized by a stable low level of physical activity throughout the follow-up. Two other trajectories were Starting low and increasing (25%) and Starting high and decreasing (23%). Nonagenarians' cognitive measures did not differ among the LTPA trajectories. DISCUSSION: Longitudinal physical activity behavior may not preserve cognitive function in those who survive to nonagenarian age but larger studies are warranted.