A systematic review and meta-analysis of 90 cohort studies of social isolation, loneliness and mortality.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective cohort studies
PubMed 37337095 · doi:10.1038/s41562-023-01617-6
What was done
This PROSPERO-registered (CRD42022299959) systematic review and meta-analysis evaluated prospective cohort studies examining associations between social isolation, loneliness, and mortality (all-cause, cardiovascular disease [CVD], and cancer) in adults aged 18 years or older, including cohorts with pre-existing CVD or cancer. The review included 90 prospective cohort studies comprising 2,205,199 individuals.
What was found
In the general population, both social isolation and loneliness were significantly associated with increased all-cause mortality (pooled effect size [ES] for social isolation: 1.32, 95% CI 1.26 to 1.39, P < 0.001; pooled ES for loneliness: 1.14, 95% CI 1.08 to 1.20, P < 0.001) and cancer mortality (pooled ES for social isolation: 1.24, 95% CI 1.19 to 1.28, P < 0.001; pooled ES for loneliness: 1.09, 95% CI 1.01 to 1.17, P = 0.030). Social isolation was also associated with increased CVD mortality (pooled ES: 1.34, 95% CI 1.25 to 1.44, P < 0.001). In clinical populations, social isolation was associated with increased all-cause mortality in individuals with CVD (pooled ES: 1.28, 95% CI 1.10 to 1.48, P = 0.001) or breast cancer (pooled ES: 1.51, 95% CI 1.34 to 1.70, P < 0.001), and higher cancer-specific mortality in individuals with breast cancer (pooled ES: 1.33, 95% CI 1.02 to 1.75, P = 0.038).
Why it matters
Synthesizing data from over two million individuals, this meta-analysis confirms that objective social isolation and subjective loneliness are robust prospective risk factors for premature mortality across general and clinical populations.
Limits
All included studies were observational cohorts, leaving open the possibility of residual confounding or reverse causation. The abstract does not report estimates for loneliness in relation to CVD mortality or specific cancer subtypes.
Cited by
- supports Social isolation has a detrimental impact on human well-being and health.