Income inequality and mortality: The role of race and residential segregation

Objective. To examine the role of race and residential segregation on the relationship between income inequality and mortality.;Study sample. This is a cross-sectional ecological study of metropolitan areas in the United States (N = 107). Metropolitan statistical areas were selected using two criteria: (1) a population of at least 100,000; and (2) at least 10% African-American.;Research methods. Data for this study come from the US Census Bureau for the 1990 and 2000 Censuses and the National Center for Health Statistics Multiple Cause of Death public use data files for the time period 1990--1999. Ordinary least squares regression was used to conduct race-specific analysis to assess both the direct and indirect effects of race on the income inequality/mortality relationship. Structural equation modeling techniques were used to examine residential segregation and concentrated poverty as mediators in the income inequality/mortality relationship.;Results. Study results show that income inequality is protective of mortality rates for both the total sample and for whites. Among African-Americans, income inequality is a positive predictor of mortality rates. These effects are not sustained after adjusting for residential segregation, suggesting that residential segregation confounds the income inequality/mortality relationship.;Racial concentration moderates the effect of income inequality on mortality such that mortality rates increase with increasing income inequality for metropolitan areas with a high percentage of African-Americans compared to metropolitan areas with a lower percentage of African-Americans. Residential segregation also moderates the income inequality/mortality relationship. Mortality rates decrease with increasing income inequality for metropolitan areas with high levels of residential segregation compared to metropolitan areas with lower levels of residential segregation.;Structural equation modeling results indicate that residential segregation mediates the income inequality/mortality relationship; and that the pathway through which income inequality effects health varies by racial group.;Conclusions. The experience of income inequality and residential segregation is not the same across racial groups. Race and racial residential segregation confound the income inequality/mortality relationship. Future studies seeking to explore the effects of income inequality on population health should specifically account for the confounding role of race and residential segregation.