Social Isolation, Physical Activity, and Subsequent Changes in Cognition Among Middle- and Older-Aged Adults: Results From the Canadian Longitudinal Study on Aging

Abstract

Objective The objectives of this study are to: 1) evaluate associations between social isolation and change in cognition over a three-year period, and 2) evaluate whether physical activity mediates the association between social isolation and cognition change. Methods Using baseline and follow-up one data from the Canadian Longitudinal Study on Aging (CLSA), latent change score models, incorporating direct and indirect pathways, were constructed to estimate the indirect effect of social isolation on cognitive change through physical activity. Multi-group models were constructed based on age-group (45-65 years versus 65+ years) and sex to allow for varying estimates across age and sex. The final analytic sample included 51,338 participants. Results Indirect effects of social isolation on cognition through physical activity were evident in males and females 65+ years for memory change (b ̂ = -0.005 [99.9% CI: -0.007 to -0.002], p < .001 in both groups) and in males adults 65+ years for EF change (b ̂ = -0.01 [99.9% CI: -0.02 to -0.006], p < .001). Statistically significant indirect effects were not observed for adults between 45-65 years. Conclusions Social isolation is associated with diminished physical activity, and in turn, diminished physical activity is associated with decline in memory in older women and men, with larger declines in executive function in older males. Public health initiatives to promote physical activity—perhaps incorporating social interaction—among older adults experiencing social isolation could be one way to mitigate the negative impact of social isolation on cognitive health.