Late‐life social activity moderates the association between temporal lobe atrophy and episodic memory decline

Abstract

AbstractBackgroundRetirement and loss of important social relationships, including spouse and friends, make older adults more vulnerable to social isolation. Therefore, social activity could be important for older adults in maintaining life satisfaction and everyday functioning. Although several studies found protective roles of social activity against cognitive decline in late life, only a few studies examined the protective effects of social activity using longitudinal data. In this study, the effects of social activity on the relationship between brain aging and cognitive decline in older adults were examined during a four‐year period.MethodThirty‐two older adults with normal cognition (mean age = 70.69, SD: 6.27, mean education = 7.75, SD: 3.94 at baseline) were recruited from the Korean Social Life, Health, and Aging Project (KSHAP). Neuropsychological and brain imaging data, and social survey, were acquired in 2015 and 2019. Elderly Verbal Learning Test (EVLT) performance and cortical volumes from Magnetic Resonance Imaging (MRI) were the main measures of interest. The participants were asked to respond either “yes” or “no” to social survey items, including participation in community senior center events, volunteering for charities, religious activities, socializing events, leisure activities, and community activities. Social activity was explored in terms of level, consistency, and types of social activities. The Computational Anatomy Toolbox (CAT) was used to calculate temporal lobe gray matter volume selected as regions of interest (ROI) for its role in episodic memory. Hierarchical regressions were conducted to examine the effects of social activity on the relationship between temporal lobe atrophy and episodic memory decline.ResultWe found that the temporal lobe atrophy was associated with the delayed recall decline (r = 0.49, p = 0.003). More involvement in social activity at baseline decreased the effects of temporal lobe atrophy on delayed recall decline, controlling for age, sex, education, and self‐rated health as covariates. Further, consistent involvement in social activity, especially volunteering, attenuated the association between temporal lobe atrophy and delayed recall decline.ConclusionThese findings suggest that social activities in late life function as cognitive reserve to buffer against the effects of temporal lobe atrophy on episodic memory decline in older adults.