Associations of Depressive Symptoms With All-Cause and Cause-Specific Mortality by Race in a Population of Low Socioeconomic Status: A Report From the Southern Community Cohort Study

Depression is a leading cause of disability in the United States, but its impact on mortality rates among racially diverse populations of low socioeconomic status is largely unknown. Using data from the Southern Community Cohort Study, 2002-2015, we prospectively evaluated the associations of depressive symptoms with all-cause and cause-specific mortality in 67,781 Black (72.3%) and White (27.7%) adults, a population predominantly with a low socioeconomic status. Baseline depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depression Scale. The median follow-up time was 10.0 years. Multivariate Cox regression was used to estimate hazard ratios and 95% confidence intervals for death in association with depressive symptoms. Mild, moderate, and severe depressive symptoms were associated with increased all-cause (hazard ratio (HR) = 1.12, 95% confidence interval (CI): 1.03, 1.22; HR = 1.17, 95% CI: 1.06, 1.29; HR = 1.15, 95% CI: 1.03, 1.28, respectively) and cardiovascular disease-associated death (HR = 1.23, 95% CI: 1.05, 1.44; HR = 1.18, 95% CI: 0.98, 1.42; HR = 1.43, 95% CI: 1.17, 1.75, respectively) in Whites but not in Blacks (P for interaction < 0.001, for both). Mild, moderate, or severe depressive symptoms were associated with increased rates of external-cause mortality in both races (HR = 1.24, 95% CI: 1.05, 1.46; HR = 1.31, 95% CI: 1.06, 1.61; HR = 1.42, 95% CI: 1.11, 1.81, respectively; for all study subjects, P for interaction = 0.48). No association was observed for cancer-associated deaths. Our study showed that the association between depression and death differed by race and cause of death in individuals with a low socioeconomic status.