Both actual isolation and the feeling of being isolated have been linked to dying earlier, and they are not the same thing. One is a count of contacts and the other is a subjective state, so they might carry very different weights. A meta-analytic review gathered studies from 1980 to 2014 with quantitative mortality data on , or living alone. How large, and which one is worse?
All three came out similar, and all three were substantial. With several confounds statistically controlled, the weighted average effects were an of 1.29 for social isolation, 1.26 for loneliness and 1.32 for living alone. Those correspond to roughly 29, 26 and 32 percent increased likelihood of mortality. There was no difference between objective and subjective isolation. The authors call the influence comparable to well-established mortality risk factors.
Actual and perceived social isolation are both associated with increased risk of early mortality, and they are conceptually distinct. One is an objective matter of how many people are around you. The other is how you feel about it. Establishing the overall and relative magnitude of each was the point of this review.
The literature search covered January 1980 to February 2014 across MEDLINE, CINAHL, PsycINFO, Social Work Abstracts and Google Scholar. It included studies providing quantitative data on mortality as affected by loneliness, social isolation or living alone.
Across studies in which several possible confounds were statistically controlled, the weighted average effects were an odds ratio of 1.29 for social isolation, 1.26 for loneliness and 1.32 for living alone. Those correspond to roughly 29, 26 and 32 percent increased likelihood of mortality. The authors found no differences between measures of objective and subjective social isolation.
The is where the caution lives. Results stayed consistent across gender, length of follow-up and world region, while initial health status influenced the findings and age did too, with social deficits more predictive of death in samples averaging under 65 years. Health status mattering is the fingerprint of reverse causation, since being ill both isolates people and kills them. The authors conclude the influence of isolation is comparable with well-established mortality risk factors, which is a claim about magnitude rather than about mechanism.
wat. Loneliness, isolation and living alone each raised the odds of dying by a quarter to a third, and feeling alone counted as much as being alone.
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Feeling isolated turned out to carry about the same weight as being isolated. That matters clinically, because a well-connected person who feels alone would not register on any count of contacts.
How do we know?
Holt-Lunstad and colleagues searched five databases for studies published between January 1980 and February 2014 providing quantitative mortality data on loneliness, social isolation or living alone, then pooled them and tested moderators.
What is still unknown
Observational studies pooled, so reverse causation is live: illness isolates people as well as the other way round. Initial health status influenced the findings, which is exactly the signature of that problem.
Learn something?
Where to next
How large is the health effect of having people around you?mortality
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