Trajectories of cognitive function in community-dwelling older adults: A longitudinal study of population heterogeneity.

Introduction This study aimed to investigate cognitive aging trajectories, the associated sociodemographic characteristics, and the association of these trajectories with dementia. Methods Generally healthy older adults (n = 19,114) were followed for up to 7 years, with regular cognitive assessments. Group-based trajectory modeling identified distinct cognitive trajectories. Results Four to seven trajectories were identified per cognitive domain. Stable trajectories were observed across domains. Improvement in verbal fluency and minor psychomotor slowing were common. Substantial decline in global cognition and episodic memory were observed in a small proportion of individuals. Older, less educated participants and men were more common in lower-functioning trajectories (p < .001). The highest proportions of dementia cases were in trajectories with major decline in global cognition (56.9%) and memory (33.2%). Discussion Inter-individual variability in cognitive trajectories was observed across all domains. Some individuals appear resilient to cognitive decline even with advancing age. Further research into factors promoting cognitive resilience is needed.