Introduction: More studies are needed to examine whether race moderates the effect of baseline depressive symptoms on cause-specific mortality including deaths due to renal diseases in the United States.
Objectives: The present longitudinal study compared Blacks and Whites for the effect of baseline depressive symptoms on deaths due to renal diseases over a 25-year period in a nationally representative community sample.
Patients and methods: Data came from the Americans' Changing Lives (ACL) study, a nationally representative cohort that followed 3361 Black (n = 1156) or White (n = 2205) adults 25 and older for up to 25 years from 1986 to 2011. Month, year and cause of death were extracted from death certificates or national death index reports and coded based on ICD-9 or ICD-10 codes, depending on the year of death. We used Cox proportional hazards models for data analysis. Time to death due to renal diseases over a 25-year period was the outcome, baseline depressive symptoms (11-item Center for Epidemiological Studies-Depression [CES-D]) was the predictor, demographic characteristics, socio-economic status and chronic medical conditions (CMC) (hypertension, diabetes, chronic lung disease, heart disease, stroke, cancer, and arthritis) at baseline were controls, and race was the focal moderator.
Results: In the pooled sample, race and baseline depressive symptoms showed a significant interaction, suggesting a stronger effect of baseline depressive symptoms on deaths due to renal diseases for Whites compared to Blacks. In race-specific models, high depressive symptoms at baseline increased risk of death due to renal diseases among Whites but not Blacks.
Conclusion: The Black-White difference in the predictive role of baseline depressive symptoms on deaths due to renal diseases over a 25-year period found here provides support for the Black-White health paradox.
Keywords: African Americans; Death; Depression; Ethnic groups; Kidney diseases; Mortality; Population groups.