Association between social integration and risk of dementia: A systematic review and meta-analysis of longitudinal studies.

Our findings reveal that high social engagement and frequent social contact are significantly associated with a lower risk of dementia, whereas loneliness is associated with a higher risk. The promising impact of large social network size is also identified. Substantial heterogeneity appeared in most of the analysis, making the inference tentative. Nevertheless, the sensitivity analysis provided valuable implications that enhancing social engagement and reducing loneliness may prevent or delay the onset of dementia among middle-aged and older adults.