County-level income inequality and depression among older Americans.

OBJECTIVES: To examine (1) whether county-level income inequality is associated with depression among Americans aged 70 and older, taking into consideration county-level mean household income and individual-level socioeconomic status (SES), demographic characteristics, and physical health, and (2) whether income inequality effects are stronger among people with lower SES and physical health.

DATA SOURCES: The individual-level data from the first wave of the Assets and Health Dynamics among the Oldest Old survey (1993-1994) were linked with the county-level income inequality and mean household income data from the 1990 Census.

STUDY DESIGN: Multilevel analysis was conducted to examine the association between income inequality (the Gini coefficient) and depression.

PRINCIPAL FINDINGS: Income inequality was significantly associated with depression among older Americans. Those living in counties with higher income inequality were more depressed, independent of their demographic characteristics, SES, and physical health. The association was stronger among those with more illnesses.

CONCLUSIONS: While previous empirical research on income inequality and physical health is equivocal, evidence for income inequality effects on mental health seems to be strong.