Abstract
BACKGROUND: Conflicting evidence exists regarding the association of socioeconomic status (SES) with mortality among older people and little is known about the mechanisms underlying this association. We investigated the association of SES with mortality among older Australian men. We also investigated potential mediating effects of health-related behaviours in SES-mortality associations. METHODS: We used data from a prospective population-based cohort (the Concord Health and Aging in Men Project), in Sydney, Australia. The main outcomes were all-cause and cause-specific mortality. Educational attainment, occupational position, source of income, housing tenure, and a cumulative SES score were assessed at baseline. Longitudinally assessed alcohol consumption, smoking, physical activity, and body mass index were investigated as potential mediators. Associations were quantified using Cox regression. RESULTS: We evaluated 1527 men (mean age: 77.4 ± 5.5 years). During a mean follow-up time of 9.0 years, 783 deaths occurred. For deaths from all causes, the adjusted hazard ratio (HR) for the lowest tertile of cumulative SES score versus the highest tertile was 1.44 (95% CI 1.21 to 1.70); the corresponding sub-HRs were 1.35 (0.96 to 1.89) for cardiovascular disease (CVD) mortality; 1.58 (1.15 to 2.18) for cancer mortality, and 1.86 (1.36 to 2.56) for non-CVD, non-cancer mortality. SES-mortality associations were attenuated by 11-25% after adjustment for mediating health-related behaviours. CONCLUSION: Low SES is associated with increased mortality in older Australian men and health-related behaviours accounted for less than one-fourth of these associations. Further research is needed to fully understand the mechanisms underlying SES inequalities in mortality among older people.