The scientists analysed data from 6,500 people aged 52 and older enrolled in the English Longitudinal Study of Ageing, which monitors the health, social well-being and longevity of people living in England. The researchers evaluated social isolation on the basis of the amount of contact participants reported having with family, friends and civic organizations, and they assessed loneliness using a questionnaire. They tracked sickness and mortality in study participants from 2004 to 2012.
The researchers found that social isolation was correlated with higher mortality — even after adjusting for pre-existing health conditions and socioeconomic factors — but loneliness was not.
“When we think about loneliness and social isolation, we often think of them as two faces of the same coin,” says Andrew Steptoe, a psychologist and epidemiologist at University College London, who led the study. But the findings suggest that a lack of social interaction harms health whether or not a person feels lonely, he says. “When you’re socially isolated, you not only lack companionship in many cases, but you may also lack advice and support from people.”Other studies, referenced in the Nature article, have suggested that loneliness is not good for your health, and the authors of this study are not discounting the negative psychological effects of loneliness, but their analysis suggests that lives are shortened by social isolation, but not necessarily by loneliness. I guess the lesson is that you can be lonely in a crowd, but the crowd is good for your health.