Associations between social determinants of health and cardiovascular and cancer mortality in cancer survivors: a prospective cohort study

Aims
The cause-specific mortality implications of social determinants of health (SDOH) in cancer survivors were unclear. This study aimed to explore associations between SDOH and cardiovascular and cancer mortality in cancer survivors.

Methods and results
Data from 2013 to 2017 National Health Interview Survey were used for this prospective cohort study. Social determinants of health were quantified using a 38 point, 6 domain score, with higher points indicating worse deprivation. Associations between SDOH and outcomes (primary: cardiovascular mortality; secondary: cancer and all-cause mortality) were assessed using cause-specific multivariable Cox regression, with cancer survivors and individuals without cancer modelled separately. Post hoc analyses were performed among cancer survivors to explore associations between each domain of SDOH and the risks of outcomes. Altogether, 37 882 individuals were analysed (4179 cancer survivors and 33 703 individuals without cancer). Among cancer survivors, worse SDOH was associated with higher cardiovascular [adjusted hazard ratio (aHR) 1.31 (1.02–1.68)], cancer [aHR 1.20 (1.01–1.42)], and all-cause mortality [aHR 1.16 (1.02–1.31)] when adjusted for demographics, comorbidities, and risk factors. Among individuals without cancer, SDOH was associated with cardiovascular mortality and all-cause when only adjusted for demographics, but not when further adjusted for comorbidities and risk factors; no associations between SDOH and cancer mortality were found. Among cancer survivors, psychological distress, economic stability, neighbourhood, physical environment and social cohesion, and food insecurity were varyingly associated with the outcomes.

Conclusion
Social determinants of health were independently associated with all-cause, cardiovascular, and cancer mortality among cancer survivors but not among individuals without cancer. Different domains of SDOH may have different prognostic importance.