The Moderating Role of Family Poverty-to-Income Ratio in the Depression-Mortality Association: A 2005-2018 NHANES Cohort Study

BackgroundTo investigate the mediating role of family poverty income ratio (PIR) in the association between depression and mortality risk, including all-cause and cardiovascular disease mortality, using data from the National Health and Nutrition Examination Survey (NHANES). MethodsThe study included a cohort of participants from seven NHANES cycles (2005-2018) with available depressive assessments and family PIR data. The primary endpoint was all-cause mortality, and the secondary endpoint was cardiovascular mortality, ascertained from National Center for Health Statistics (NCHS) mortality follow-up data. To evaluate the relationship between depression and mortality, we employed restricted cubic splines (RCS), Cox proportional hazards regression models. After adjusting for covariates such as age, sex, education, and marital status, mediation analysis was conducted to assess the mediating effects of the family PIR on these associations. ResultsThe prevalence of depressive symptoms among the 33,132 participants was 8.64%, with a mean age of 47.62 {+/-} 18.69 years. After adjusting for multiple confounders, higher Patient Health Questionnaire-9(PHQ-9) scores were significantly associated with an increased risk of all-cause mortality (HR = 1.050, 95% CI: 1.042-1.058, P < 0.0001) and cardiovascular mortality (HR = 1.035, 95% CI: 1.019-1.050, P < 0.00001). Mediation analysis revealed that 14.51% and 5.82% of the effects of depression on all-cause and cardiovascular mortality, respectively, were mediated through family PIR. ConclusionThe family PIR plays a partial mediating role in the relationship between depressive and mortality risk, highlighting the importance of socioeconomic factors in understanding and reducing depression-related mortality. Interventions targeting both mental health and socioeconomic support are essential to improve overall survival among individuals with depression.