Distinguishing the race-specific effects of income inequality and mortality in U.S. metropolitan areas.

In the United States, the association between income inequality and mortality has been fairly consistent. However, few studies have explicitly examined the impact of race. Studies that have either stratified outcomes by race or conducted analyses within race-specific groups suggest that the income inequality/mortality relation may differ for blacks and whites. The factors explaining the association may also differ for the two groups. Multivariate ordinary least squares regression analysis was used to examine associations between study variables. We used three measures of income inequality to examine the association between income inequality and age-adjusted all-cause mortality among blacks and whites separately. We also examined the role of racial residential segregation and concentrated poverty in explaining associations among groups. Metropolitan areas were included if they had a population of at least 100,000 and were at least 10 percent black. There was a positive income inequality/mortality association among blacks and an inverse association among whites. Racial residential segregation completely attenuated the income inequality/mortality relationship for blacks, but was not significant among whites. Concentrated poverty was a significant predictor of mortality rates in both groups but did not confound associations. The implications of these findings and directions for future research are discussed.