Association Between Depression and All-Cause Mortality : A Cohort Study Based on NHANES Data

BackgroundDepression is a common mental disorder that significantly influences mental health outcomes and increases the risk of all-cause mortality. However, the dose-response relationship between depression and all-cause mortality remains unclear. MethodsA total of 36,193 participants from the National Health and Nutrition Examination Survey (NHANES) 2005-2018 were included in this study. Depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9) scale, and all-cause mortality data were obtained from the National Death Index. Weighted Cox regression models were applied to evaluate the association between depression and all-cause mortality, with special attention to non-linear relationships. ResultsAmong the study population, 8.74% were identified as having depression. The mean follow-up duration was 90.53 months, during which 9.87% of participants died from all causes. A significant non-linear association was observed between PHQ-9 scores and all-cause mortality. All-cause mortality increased markedly with depression scores [&le;] 7 (HR: 1.068, 95% CI: 1.042-1.095, P < 0.0001) and plateaued when scores approached 7. ConclusionsElevated depressive symptoms, even at mild levels, are associated with a substantial increase in all-cause mortality. These findings underline the necessity for early identification and intervention for depressive symptoms to reduce long-term adverse health outcomes. This research provides critical evidence to inform public health strategies targeting the reduction of depression-related mortality.