Does psychological distress contribute to racial and socioeconomic disparities in mortality?

Being black or poor are powerful predictors of mortality. Although psychological distress has been proposed as mediating the effects of race and socioeconomic status on mortality, this hypothesis has not been previously directly tested. We used data from the National Health and Nutrition Examination I (NHANES I), a nationally representative sample from the U.S, and the NHANES I Epidemiological Follow-up Survey (NHEFS) of subsequent mortality to test this hypothesis. Both black race and lower family income were associated with significantly higher psychological distress as measured at the time of the initial survey by reports of hopelessness, depression, and life dissatisfaction. Black race and low income in addition to each of the measures of psychological distress were associated with higher mortality at follow-up. In a series of Cox proportional hazards models that controlled for the effects of age and gender, additional adjustment for hopelessness, depression, or life dissatisfaction had little effect on the relationship between either African American race or family income and subsequent all-cause mortality. We conclude that the effects of both race and income on mortality are largely independent of psychological distress. These findings do not support the hypothesis that psychological distress is a significant mediator of the effects of race or class on health.