Loneliness and Cognitive Function in Older Adults Without Dementia: A Systematic Review and Meta-Analysis

Abstract

Background: Loneliness has been highlighted as a risk factor for dementia. However, the nature of the relationship between loneliness and cognitive function prior to onset of dementia is unclear. Objective: The aim of this systematic review and meta-analysis was to examine the relationship between loneliness and cognitive function in samples screened for dementia at study commencement. Methods: Five electronic databases (PubMed, PsycNET, Web of Science, EBSCOhost, Scopus) were searched from inception to August 31, 2021. A narrative review and random-effects meta-analysis were conducted on studies meeting search criteria. PROSPERO registration number: CRD42020155539. Results: The sixteen studies that met inclusion criteria involved 30,267 individuals, with mean age ranging from 63.0 to 84.9 years. Studies varied in dementia screening criteria, measurement of loneliness and cognitive function, and statistical modeling approach. The narrative review indicated that loneliness was associated with poorer global cognition, episodic memory, working memory, visuospatial function, processing speed, and semantic verbal fluency. Results of the meta-analysis indicated that loneliness was negatively associated with global cognitive function (overall r = –0.08; 95% CI = –0.14, –0.02; n = 6). Due to lack of sufficient data and heterogeneity between studies, we were unable to explore associations with other cognitive domains or longitudinal associations. Conclusion: Loneliness is associated with subtle impairment across multiple cognitive domains in older adults who were screened for dementia. Better characterization of this relationship will provide important information about how loneliness contributes to the clinical and pathological sequalae of AD and be informative for risk reduction and early detection strategies.

Self-Care Practices and Health-Seeking Behaviors Among Older Adults in Urban Indian Slums: A Mixed Methods Study

“…In contrast to total self-reliance, family assistance improves diet and medication compliance. Lower self-efficacy among widowed older adults predicts self-neglect risks [ 25 ], necessitating targeted interventions promoting independence.…”

Social Disconnectedness, Perceived Loneliness, and Cognitive Functioning: The Role of Neighborhood Environment

“…A number of studies assessed the associations of the objective and subjective aspects of social relationships, including social disconnectedness and perceived loneliness, with cognitive functioning ( Evans, Martyr et al, 2019 ; Lara et al, 2019 ). The existing literature mostly documented the adverse effects of perceived loneliness, limited social support, small social networks, and low levels of social engagement on the increased risk of cognitive decline and impairment ( Boss et al, 2015 ; Evans, Martyr et al, 2019 ; Harrington et al, 2023 ; Lara et al, 2019 ; Okamoto & Kobayashi, 2021 ). However, a few studies reported nonsignificant associations between various aspects of social relationships and cognitive measures ( Boss et al, 2015 ; Harrington et al, 2023 ; Kuiper et al, 2016 ).…”

“…According to a cognitive reserve perspective, maintaining a diverse range of social networks and actively engaging in social activities can offer mental stimulation, thereby fostering cognitive reserve, or the capacity to withstand cognitive decline caused by age-related brain pathology ( Evans, Llewellyn et al, 2019 ; Stern, 2002 , 2012 ). Evidence suggests that social disconnectedness poses a risk for cognitive impairment; yet the association between social disconnectedness and cognition remains inconclusive, with conflicting findings reported in the literature ( Boss et al, 2015 ; Evans, Martyr et al, 2019 ; Harrington et al, 2023 ; Kuiper et al, 2016 ). Feelings of loneliness, on the other hand, are common among older adults and have profound consequences, including impaired cognitive performance, cognitive decline, and an increased risk of Alzheimer’s disease and related dementias ( Hawkley & Cacioppo, 2010 ).…”

A preliminary study on the neurocognitive deficits associated with loneliness in young adults

“…Some inconsistencies in the results, nonetheless, are present such that some studies [e.g., (8)] have reported a bidirectional relationship between loneliness and cognition, while a prospective study by McHugh Power et al (9) found that attention may affect loneliness but not vice versa. A recent metaanalysis of older adults without dementia (10) found that loneliness was associated with poorer global cognition, episodic memory, working memory, visuospatial function, processing speed, and semantic verbal fluency.…”