People with stronger social relationships had a 50% increased likelihood of survival over the follow-up period. The effect held across age, sex, initial health status and cause of death. It was strongest for complex measures of social integration and weakest for crude indicators like living alone.
How it was done
A meta-analysis of 148 studies covering 308,849 participants, with an average follow-up of 7.5 years.
What it means
The moderator is more interesting than the headline. The association is strongest for multidimensional measures of social integration and weakest for "how many people do you live with" — structure and quality matter more than headcount.
The authors note the magnitude is comparable to quitting smoking and exceeds obesity and physical inactivity, which is why this meta-analysis is cited so widely outside its field.
The WHO reached a similar conclusion in 2025, estimating that loneliness affects around one in six people worldwide and is linked to some 871,000 deaths a year.
A 2023 meta-analysis in Nature Human Behaviour (Wang et al., 90 cohort studies, 2.2 million people) updated the picture and split it: being socially isolated went with a 32% higher risk of death from any cause, feeling lonely with 14%. What people have counts for more in this literature than how they feel about it.
