Prevalence of loneliness and social isolation among individuals with mild cognitive impairment or dementia: systematic review and meta-analysis.

Background: A systematic review/meta-analysis synthesising the existing evidence regarding the prevalence of loneliness and social isolation among individuals with mild cognitive impairment (MCI) or dementia is lacking.

Aims: A systematic review and meta-analysis was conducted to investigate the prevalence and factors associated with loneliness and social isolation among individuals with MCI or dementia.

Method: A search was conducted in five established electronic databases. Observational studies reporting prevalence and, where available, factors associated with loneliness/isolation among individuals with MCI and individuals with dementia, were included. Important characteristics of the studies were extracted.

Results: Out of 7427 records, ten studies were included. The estimated prevalence of loneliness was 38.6% (95% CI 3.7-73.5%, = 99.6, < 0.001) among individuals with MCI. Moreover, the estimated prevalence of loneliness was 42.7% (95% CI 33.8-51.5%, ² = 90.4, < 0.001) among individuals with dementia. The estimated prevalence of social isolation was 64.3% (95% CI 39.1-89.6%, ² = 99.6, < 0.001) among individuals with cognitive impairment. Study quality was reasonably high. It has been found that living alone and more depressive symptoms are associated with a higher risk of loneliness among individuals with dementia.

Conclusions: Social isolation, and in particular loneliness, are significant challenges for individuals with MCI and dementia. This knowledge can contribute to supporting successful ageing among such individuals. Future research in regions beyond Asia and Europe are clearly required. In addition, challenges such as chronic loneliness and chronic social isolation should be examined among individuals with MCI or dementia.