Social Integration, Social Support and Mortality in the US National Health Interview Survey

Background: Social relationship quantity and quality are associated with mortality, but it is unclear whether each relationship dimension is equally important for longevity and whether these associations are sensitive to baseline health status. Methods: This study examined the individual and joint associations of relationship quantity (measured using a social integration score) and quality (measured by perceived social support) with mortality in a representative US sample (n = 30,574). The study also evaluated whether these associations were consistent across individuals with and without diagnosed chronic illness and whether they were independent of socioeconomic status (SES; education, income, employment, and wealth). Baseline data were collected in 2001 and were linked to vital status records 5 years later (1836 deaths). Results: Both social integration and social support were individually related to mortality (hazard ratios [HRs] = 0.83 [95% confidence interval {CI} = 0.80-0.85] and HR = 0.94 [95% CI = 0.89-0.98], respectively). However, in multivariate models including demographic and SES variables, social integration (HR = 0.86, 95% CI = 0.83-0.89) but not social support (HR = 1.03, 95% CI = 0.98-1.08) was associated with mortality. The social integration association was linear and consistent across baseline health status and men and women. Conclusions: Social integration but not social support was independently associated with mortality in the US sample. This association was consistent across baseline health status and not accounted for by SES.