The spatial segregation of poverty is associated with higher mortality in Porto Alegre , Brazil

Background: The link between poverty and poor health outcomes is well known; more recently there is some evidence that suggests an independent effect of income inequality on health. However this association of income inequality with health appears to be weaker at smaller spatial levels. The paper examines the question whether socioeconomic segregation at the neighbourhood level, which is the spatial manifestation of income inequality, is associated with higher mortality rates. Methods: Data on mortality rates, income, income inequality (gini coefficient) and income segregation were analysed for all 73 districts within the city of Porto Alegre, Brazil. The outcomes in this study are district level standardized mortality rates for total mortality, premature cardiovascular mortality and infectious disease causes mortality. Census data were used to calculate the proportion of income groups at census tract level (n = 2,157) and to calculate global segregation scores for the city and local segregation scores for localities within the city. Results: The results demonstrate the existence of income inequality and income segregation within the city and a relationship, at district level, between these measures and health outcomes. There is some evidence to suggest that income segregation is associated with population health over and above the effects of income and income inequality. If poor people are completely isolated in the neighbourhoods where they live, those districts have around 14 deaths per 1000 population more than districts where poor people are not isolated in their neighbourhoods. Conclusion: The residential segregation of poor people within cities may need to be addressed, along with income inequality, if health inequalities are to be reduced. Urban and economic development that results in increasing the spatial segregation of poor people may result in widening health inequalities.