2022 Theses Master's

Associations between Social Isolation, Loneliness, Cognition, and Dementia: Implications for Clinical Practice, Social Engagement Interventions, and Public Policy

Reid, Scott

Background: Social isolation and loneliness have been found to be common among older adults. The absolute number of individuals experiencing social isolation and loneliness will rise dramatically as a large proportion of the population reaches old age. Numerous studies have found associations between social isolation, loneliness, cognition, and dementia. However, the findings regarding these associations have been mixed.

Methods: This review aimed to clarify these associations. A search of the literature identified a total of 1,070 related articles. After deduplication by title, removal of articles based on exclusion criteria, and the addition of one article published shortly after the initial search that met inclusion criteria, a total of 27 articles using longitudinal cohort data remained. Each article was reviewed for associations between social isolation, loneliness, and cognitive functioning in older adults.

Results: Four main relationships emerged: 1) social isolation and cognition, 2) social isolation and dementia, 3) loneliness and cognition, and 4) loneliness and dementia. Social isolation and loneliness were found to be significantly associated with declines in cognitive performance, and loneliness was found to be associated with an increased risk of dementia. However, the association between social isolation and risk of dementia was found to be non-significant in all studies reviewed. Further, it was found that key covariates, such as age, gender, and depression, may have moderating effects on cognitive performance.

Discussion: This review has important implications for cognitive aging and public health. Further clarifying these associations through the standardization and harmonization of study design and methods will help identify targets for clinical practice, social engagement interventions, and public policy to help older adults optimize their cognitive health.