Loneliness, social isolation linked to higher risk of early death, study finds
(CNN) -- If you're lonely or socially isolated, you might have a higher risk of early death, according to a large new study.
There have been many studies on the associations between social isolation, loneliness and the risk of dying early, but some results have been controversial or mixed, according to the paper published Monday in the journal Nature Human Behaviour. Those conflicting results could be due to research only focusing on a specific group or region, said Turhan Canli, a professor of integrative neuroscience in the Department of Psychology at New York's Stony Brook University. Canli wasn't involved in the study.
The new paper, however, is a meta-analysis of 90 studies that had examined the links between loneliness, social isolation and early death among more than 2 million adults. Study participants were followed for anywhere from six months to 25 years.
People who experienced social isolation had a 32% higher risk of dying early from any cause compared with those who weren't socially isolated. Participants who reported feeling lonely were 14% more likely to die early than those who did not.
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The research "gives us even greater confidence" about the importance of social isolation and loneliness as independent risk factors for premature death, said Julianne Holt-Lunstad, a professor of psychology and neuroscience at Brigham Young University in Utah, who wasn't involved in the study. Holt-Lunstad was the lead scientist on the US Surgeon General's recent advisory report on social isolation and loneliness.
Social isolation, as defined by the new study, occurs when someone has an objective lack of contact with other people and can involve having a limited network or living alone.
Loneliness, on the other hand, refers to the subjective distress people feel if there's a discrepancy between the quality of social relationships they actually have and what they want, according to the meta-analysis. Someone in this situation may feel their relationships are unsatisfying if they don't fulfill their needs for connection or intimacy, said Anthony Ong, a professor of psychology and director of the Center for Integrative Developmental Science and Human Health Labs at Cornell University in New York state. Ong wasn't involved in the research.
"Americans are spending more and more time in isolation and yet we don't see it as a danger — particularly if it is by choice. People assume that it's okay and may even be good for us to be isolated if we don't feel lonely," Holt-Lunstad said via email. "Yet this data confirms and expands on previous data that documents the risk associated with social isolation regardless of and independent of loneliness."
Loneliness and isolation in the body
Being socially isolated or lonely can be considered a form of stress, Canli said.
"We all may feel lonely from time to time, but when that feeling is permanent, it may act as a form of chronic stress, which is unhealthy," Canli said via email. "One way in which that may occur is through stress hormones that adversely affect the body."
The study authors also looked into the links between loneliness, social isolation and death among people with cardiovascular disease or breast or colorectal cancer — since previous studies have shown that the relationship between social support and health can be a chicken-and-egg matter, "which could lead to a vicious cycle where poor health causes patients to lose social support … over time, but patients tend to need social support more than the general population," according to the study.
Participants who were socially isolated and had cardiovascular disease were more likely to die early than those without the disease. And socially isolated people with breast cancer had a higher risk of dying from the disease than those who weren't socially isolated.
Dying early from any cause or cardiovascular disease might also be related to people's lifestyle behaviors, Canli said: "People who feel socially isolated or lonely tend to have unhealthy habits, such as smoking, alcohol use, poor diet (or) little exercise."
There are several factors that could contribute to social isolation having a stronger effect on early death risk than loneliness, experts say.
"People who are lonely but not socially isolated have mental health stress but might be resilient to it because of their social networks" — even if those networks aren't entirely what someone wants them to be, said the study's first author Fan Wang, a professor of epidemiology at Harbin Medical University in China.
Having a small social network or little to no contact with the outside world can also make someone less likely to receive medical care if they don't have anyone checking on them, Canli said.
"While this meta-analysis is important in providing corroborating evidence of the detrimental effects of social isolation and loneliness, there is a pressing need to move beyond questions concerning the independent effects to a consideration of their joint interplay," said Ong, who was also among the scientists involved in the Surgeon General's report, via email.
This further study would pave "the way for a deeper understanding and effective interventions," he added.
Broadening social connections
People experiencing social isolation and loneliness should actively seek social support, Wang said.
"Think of maintaining a social network like any other health-promoting activity: exercising regularly, eating well, looking after yourself," Canli said. Make cultivating your social connections a priority by not limiting when you say "hey" to someone to just holidays, or by thinking of ways to engage in activities that may expose you to new circles of like-minded people, he added.
Public health strategies to address loneliness and social isolation, including raising awareness, are also needed, Wang said.
Developing interventions with the help of family members and community networks is critical, Wang said. The health care system should also develop methods for identifying social isolation and loneliness in patients so health professionals can provide the appropriate help, he added.