Holt-Lunstad · Perspectives on psychological science : a journal of the Association for Psychological Science 2015 · systematic review and meta-analysis · n=?

Loneliness and social isolation as risk factors for mortality: a meta-analytic review.

Level 2 - randomized trial

Systematic review and meta-analysis of observational cohort studies

PubMed 25910392 · doi:10.1177/1745691614568352 · record verified 2026-08-26

What was done

Method and design, enough to judge the result. From the abstract only. A systematic literature search (January 1980 to February 2014) was conducted across MEDLINE, CINAHL, PsycINFO, Social Work Abstracts, and Google Scholar. Studies providing quantitative data on early mortality as affected by objective social isolation, loneliness (perceived isolation), or living alone were meta-analyzed. Weighted average effect sizes were calculated across studies statistically controlling for confounds, and potential moderators (e.g., age, gender, follow-up length, world region, initial health status) were evaluated.

What was found

The actual numbers and directions reported. Not a paraphrase of the conclusion; if the abstract gives no numbers, say so. Across studies controlling for potential confounds, the weighted average effect sizes were: social isolation odds ratio (OR) = 1.29 (29% increased likelihood of mortality), loneliness OR = 1.26 (26% increased likelihood), and living alone OR = 1.32 (32% increased likelihood). No differences were found between objective and subjective measures. Effects remained consistent across gender, follow-up length, and world region, but differed by age (more predictive of death in samples with mean age <65 years) and were influenced by initial health status.

Why it matters

What this paper adds. One or two sentences, no hype. This meta-analysis demonstrates that both actual and perceived social isolation confer a substantial independent risk for early mortality comparable to established medical risk factors.

Limits

Sample size, population, design weaknesses, what was not measured. This section is mandatory and must be substantive. The abstract does not report the total number of included studies, total participant sample size (n), or confidence intervals for the odds ratios. Because the underlying primary studies are observational, residual confounding and reverse causation cannot be fully eliminated, as reflected by the moderating influence of initial health status.

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