The results suggest that lack of social contact is a more significant risk factor than loneliness.
“In many ways, social isolation and loneliness are two sides of the same coin,”explained Steptoe. “Social isolation indicates a lack of contact with friends, relatives and organizations, while loneliness is a subjective experience of lack of companionship and social contact.”
But why isolation is such a potent predictor of death isn’t immediately obvious.
According to Julianne Holt-Lunstad, there may be two possible mechanisms by which a thriving social network of friends and family could contribute to good health.
First, the ongoing support of other people may reduce the harmful effects of stress (even if someone is happy in their solitude); it could be that isolation reduces immune function. And second, the influence of others may also encourage behaviour that contributes to good health (such as eating properly, taking medications, and practicing proper hygiene).
Steptoe agrees, saying that, “When you’re socially isolated, you not only lack companionship in many cases, but you may also lack advice and support from people.”