Social relationships and risk of dementia: A systematic review and meta-analysis of longitudinal cohort studies.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective observational cohort studies.
PubMed 25956016 · doi:10.1016/j.arr.2015.04.006
What was done
A systematic literature search was conducted to identify longitudinal cohort studies investigating social relationship factors and incident dementia in the general population. Relative risks (RRs) with 95% confidence intervals (CIs) across 19 identified studies were pooled using random-effects meta-analysis.
What was found
Statistically significant associations with incident dementia were observed for 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 loneliness (RR: 1.58, 95% CI: 1.19–2.09). Social network size showed inconsistent associations. Low satisfaction with social networks was not significantly associated with dementia onset (RR: 1.25, 95% CI: 0.96–1.62).
Why it matters
This meta-analysis demonstrates that poor social interaction is a significant risk factor for incident dementia, with relative risks comparable to established risk factors such as physical inactivity, late-life depression, and low educational attainment.
Limits
The findings are derived from observational cohort studies, which are subject to residual confounding and reverse causation (pre-clinical cognitive decline causing social withdrawal). The abstract does not provide the total participant count, follow-up durations, or statistical heterogeneity measures across studies.
Cited by
- supports Maintaining or increasing social relationships in older age is associated with a significantly reduced risk of developing dementia.