[Correlation between homicide rates and economic indicators in São Paulo, Brazil, 1996]

Around 30% of the deaths due to violent causes in Brazil result from homicides. Violence has traditionally been related to larger social problems, such as poverty. Recently, however, a positive correlation has been observed between higher incomes and an increase in the homicide rate, so that some researchers have begun to consider inequality, rather than poverty, as an explanation for the epidemic of violence. The objective of this study was to investigate the correlation between urbanization, poverty, and economic inequality and homicide rates in the state of São Paulo, Brazil, in 1996. Information regarding population size, average monthly income of household heads, income distribution, and Gini index was obtained for each municipality, based on the demographic census. Homicide rates were calculated based on official data. Data were analyzed in terms of correlation and relative risk with 95% confidence intervals. Homicide rates rose in direct proportion to city population and ranged from 6.96 (per 100,000 inhabitants) in municipalities with a population smaller than 10,000 inhabitants, to 55.54 in municipalities with more than 1 million inhabitants. Relative risk ranged from 1.35 to 7.98. A significant correlation with population size was found only for incomes above 3.11 times the minimum wage and a Gini index greater than 0.50. There was a strong, direct, and significant correlation between homicide rates and the income ratio between the ninetieth and the twentieth percentiles of the population. It is necessary to probe more deeply into the macrosocial determinants of homicide rates in order to identify indicators of inequality that can generate meaningful data for developing public health strategies.