Cumulative social disadvantage and all-cause mortality in the United States: findings from a national study

The extent to which cumulative social disadvantage-defined as aggregate social risk resulting from multiple co-occurring adverse social determinants of health (SDOH)-affects the risk of all-cause mortality, independent of demographic and clinical risk factors, is not well understood. The objective of this study was to examine the association between cumulative social disadvantage, measured using a comprehensive 47-factor SDOH framework, and mortality in a nationally representative sample of adults in the United States. The authors conducted secondary analysis of pooled data for 63,540 adult participants of the 2013-2015 National Death Index-linked National Health Interview Survey. Age-adjusted mortality rates (AAMRs) were reported by quintiles of aggregate SDOH burden, with higher quintiles denoting greater social disadvantage. Cox proportional hazards models were used to examine the association between cumulative social disadvantage and risk of all-cause mortality. AAMR increased significantly with greater SDOH burden, ranging from 631 per 100,000 person-years (PYs) for participants in SDOH-Q1 to 1490 per 100,000 PYs for those in SDOH-Q5. In regression models adjusted for demographics, being in SDOH-Q5 was associated with 2.5-fold higher risk of mortality, relative to Q1 (adjusted hazard ratio [aHR] = 2.57 [95% confidence interval, CI = 1.94-3.41]); the observed association persisted after adjusting for comorbidities, with over 2-fold increased risk of mortality for SDOH-Q5 versus Q1 (aHR = 2.02 [95% CI = 1.52-2.67]). These findings indicate that cumulative social disadvantage is associated with increased risk of all-cause mortality, independent of demographic and clinical factors. Population level interventions focused on improving individuals' social, economic, and environmental conditions may help reduce the burden of mortality and mitigate persistent disparities