Loneliness predicts mortality risk via the erosion of purpose in life.

Loneliness is associated with premature mortality risk. Less is known about the mechanisms that may explain this association. Given its consequential health associations and relation to loneliness, purpose in life may be one such mechanism. In a prospective rotating split-sample design from 2008-2010 to 2012-2014 with 11 years of mortality status follow-up, we tested purpose in life as an indirect pathway between loneliness and future risk of death. Participants were from the Health and Retirement Study in the United States (N = 8351; M[SD] = 67.9 [9.19] years; range: 50-101; 60 % female; n = 1191 deceased). Purpose in life explained an estimated 88 % of the association between loneliness and mortality risk, with the majority of the mediated association appearing to reflect changes in purpose in life over time. These effects were independent of loneliness change during follow-up and initial levels of purpose in life. This indirect path was robust to sensitivity analyses, and further adjustment for conceptually similar constructs, such as depression, social isolation, and neuroticism. A supplemental model that tested purpose in life as the antecedent and loneliness as the indirect pathway indicated substantially smaller effects. Much of loneliness-mortality relation operated through purpose in life. Purpose in life appears to be a critical factor in the context of loneliness. It may prove fruitful to pay particular attention to the individual, community, and broader societal sources of purpose in life when looking to ameliorate the effect of loneliness on health.