Objectives: Both physical functioning and cognitive abilities are important for well-being, not least in old age. Grip strength is often considered an indicator of general vitality and, as such, may predict cognitive functioning. Few longitudinal studies have examined the relationship between grip strength and cognition, especially where specific cognitive abilities have been targeted.
Method: Participants (n = 708, age range: 40-86 years at baseline) came from the population-based longitudinal Swedish Adoption/Twin Study of Aging. We used a longitudinal follow-up of 6 waves during 20 years. For the analyses, we used latent growth modeling, where latent growth trajectories were fitted to the cognitive traits (verbal ability, spatial ability, processing speed, and memory) or to the grip strength values and each, respectively, treated as time-varying covariates of the other trait.
Results: Results supported a longitudinal influence of grip strength on changes in cognitive function. Grip strength performance was associated with change in the 4 cognitive abilities after age 65 years.
Discussion: A rather stable connection was found between grip strength and cognitive abilities starting around 65 years of age. The starting period suggests that the association may be due to lifestyle changes, such as retirement, or to acceleration of the aging processes.
Keywords: Cognition; Grip strength; Longitudinal; Time-varying covariates.
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