An analysis of 148 studies found that people with strong social ties had 50% better odds of survival, an effect on par with quitting smoking
Doctors routinely ask patients about smoking, drinking, exercise and weight. Few ask about friends. In 2010, a team led by psychologist Julianne Holt-Lunstad at Brigham Young University set out to measure how much social relationships matter for survival.
In a meta-analysis published in PLOS Medicine, the researchers combined data from 148 studies that together followed 308,849 people for an average of about seven and a half years. The studies measured social relationships in different ways, from marital status and living alone to the size of a person’s social network and how supported they felt.
Across all of them, people with stronger social relationships had about 50% greater odds of being alive at the end of follow-up than people with weaker ones. The link held after accounting for age, sex, initial health and cause of death.
To put that in perspective, the researchers compared it with other well-known risk factors. The size of the effect was comparable to quitting smoking and larger than the effects linked to physical inactivity and obesity in similar analyses.
The strongest associations came from measures of how well people were integrated into a social world, such as how involved they were in relationships and community life, rather than simple yes-or-no measures like whether someone lived alone.
There are several possible explanations. People with close relationships may be encouraged to look after their health, get help when they are ill and stick to treatment. Social support may also buffer the effects of stress on the body, including on blood pressure and immune function. Loneliness itself has been linked to poorer sleep and higher levels of inflammation.
Since then, loneliness has moved up the public health agenda. In 2023, the US Surgeon General issued an advisory describing an epidemic of loneliness, and several countries have appointed ministers or launched strategies to address it.
The findings do not mean that every lonely person will die early, or that more friends automatically means longer life. The studies were observational, so they show strong associations, not proof of cause and effect, and people who are already ill may withdraw from social life. But the consistency across so many studies makes a strong case that social connection belongs in conversations about health alongside diet and exercise.
For individuals, that can be as simple as treating time with friends and family, joining a group, or reaching out to someone who might be isolated as an investment in health, not just a pleasant extra.
Source
Holt-Lunstad J, Smith TB, Layton JB. “Social relationships and mortality risk: A meta-analytic review.” PLOS Medicine, 2010.
DOI: 10.1371/journal.pmed.1000316
