From Marginal Revolution:

A new Brigham Young University study adds our social relationships to the “short list” of factors that predict a person’s odds of living or dying. In the journal PLoS Medicine, BYU professors Julianne Holt-Lunstad and Timothy Smith report that social connections – friends, family, neighbors or colleagues – improve our odds of survival by 50 percent.  

This study joins a growing body of evidence that the strength of social networks is important for longevity and quality of life. We are, after all, social animals.