Social relationships and risk of dementia: A systematic review and meta-analysis of longitudinal cohort studies

Ageing Res Rev. 2015 Jul:22:39-57. doi: 10.1016/j.arr.2015.04.006. Epub 2015 May 5.


It is unclear to what extent poor social relationships are related to the development of dementia. A comprehensive systematic literature search identified 19 longitudinal cohort studies investigating the association between various social relationship factors and incident dementia in the general population. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled using random-effects meta-analysis. Low social participation (RR: 1.41 (95% CI: 1.13-1.75)), less frequent social contact (RR: 1.57 (95% CI: 1.32-1.85)), and more loneliness (RR: 1.58 (95% CI: 1.19-2.09)) were statistically significant associated with incident dementia. The results of the association between social network size and dementia were inconsistent. No statistically significant association was found for low satisfaction with social network and the onset of dementia (RR: 1.25 (95% CI: 0.96-1.62). We conclude that social relationship factors that represent a lack of social interaction are associated with incident dementia. The strength of the associations between poor social interaction and incident dementia is comparable with other well-established risk factors for dementia, including low education attainment, physical inactivity, and late-life depression.

Keywords: Dementia; Loneliness; Social contact; Social network; Social participation; Social relationships.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Aging / psychology*
  • Dementia* / epidemiology
  • Dementia* / psychology
  • Humans
  • Interpersonal Relations*
  • Longitudinal Studies
  • Risk Assessment
  • Risk Factors
  • Social Environment*
  • Social Participation / psychology*
  • Social Support