Social contact frequency and all-cause mortality: a meta-analysis and meta-regression.

Social contact frequency is a well-defined and relatively objective measure of social relationships, which according to many studies is closely associated with health and longevity. However, no previous meta-analysis has isolated this measure; existing reviews instead aggregate social contact with other diverse measures of social support, leaving unexplored the unique contribution of social contact to mortality. Furthermore, no study has sufficiently explored the factors that may moderate the relationship between contact frequency and mortality. We conducted meta-analyses and meta-regressions to examine 187 all-cause mortality risk estimates from 91 publications, providing data on about 400,000 persons. The mean hazard ratio (HR) for mortality among those with lower levels of social contact frequency was 1.13 (p < 0.05) among multivariate-adjusted HRs. However, sub-group meta-analyses show that there is no significant relationship between contact and mortality for male individuals and that contact with family members does not have a significant effect. The moderate effect sizes and the lack of association for some subgroups suggest that mere social contact frequency may not be as beneficial to one's health as previously thought.