Association of depressive symptoms with all-cause, cardiovascular, and cancer mortality: A population-based study in Spain

INTRODUCTION Depression affects 4.4% of the global population and is associated with an increased risk of disability and premature mortality. Below we evaluate the association between depression and mortality in the adult population of Spain. MATERIAL AND METHODS We conducted aongitudinal study using data from the 2014 European Health Interview Survey for Spain, including participants aged ≥ 15 years (n=22,652), associated with the national mortality registry up to December 2023. Depression was self-reported using the 8-item Patient Health Questionnaire (PHQ-8) and measured once at baseline, with a score ≥ 10 being indicative of moderate-to-severe depressive symptoms. We explored the effect of a prior physician-diagnosis of depression and antidepressant treatment received within the previous two weeks. Age-standardized rate ratios (SRR) and differences (SRD) for all-cause, cardiovascular, and cancer mortality were estimated using Poisson regression. RESULTS Compared with individuals with no or mild depressive symptoms, those with a PHQ-8 score ≥ 10 had an SRR of 1.33 (95%CI, 1.16, 1.54), with an estimated SRD of 3.94 per 1,000 person-years (95%CI, 1.78, 6.11). For cardiovascular and cancer mortality, the SRR was 1.30 (95%CI, 1.00, 1.67) and 1.09 (95%CI, 0.79, 1.50), respectively. Among individuals with PHQ-8 ≥ 10, those with a prior diagnosis had an SRR for all-cause mortality of 1.18 (95%CI, 0.92, 1.50) vs 1.60 (95%CI, 1.31, 1.95) in those with no prior diagnosis (P = .006). Similarly, participants with PHQ-8 ≥ 10 who had received pharmacotherapy showed lower mortality risk than untreated individuals (P = .044). CONCLUSIONS Individuals with moderate-to-severe depressive symptoms, particularly those undiagnosed and/or not receiving treatment, have an increased risk of all-cause and cardiovascular mortality.