Individual participant data meta-analysis of studies of the association between psychosocial factors and the risk of cancer

An individual patient data meta-analysis by the Psychosocial Factors and Cancer Incidence consortium evaluated the association between psychosocial factors (perceived social support [PSS], loss, relationship status, neuroticism, and general distress) and the risk of cancer. The analysis used data from 22 cohorts with a baseline measure of at least one psychosocial variable of interest (n=421,799; cancer incidence n=35,319; follow-up 4,378,582 person-years). No psychosocial factors were associated with increased risk of overall cancer and with breast, prostate, and colorectal cancer, as well as with cancers with alcohol as a common potential causal factor. PSS, currently not in a relationship, and a loss event were associated with an increased risk of lung cancer (HR 1.09-1.55). Estimates decreased for PSS and relationship status after adjustment for several known risk factors such as family history of cancer (HR 1.05-1.08). Similar findings were observed for relationship status and cancers with tobacco smoking as a common potential causal factor. The authors conclude that for most types of cancer, psychosocial factors measured at a single timepoint were not associated with increased risk. PSS, currently not being in a relationship, and loss were associated with an increased risk of lung cancer, although most effects attenuated when adjusting for several known risk factors.