Objective: To describe inequalities in the infant mortality rate (IMR) according to socioeconomic indicators among geographic areas and municipalities in Brazil.
Methods: This was an exploratory ecological study of space aggregates that described IMR in 2006-2008 according to municipalities, states, and the Family Development Index (FDI), a socioeconomic indicator that ranges from 0 to 1. All the municipalities in Brazil were categorized according to four strata as defined by FDI quartiles, where stratum 4 included those with better FDI conditions, and stratum 1, worse conditions. The selected inequality measures were: Concentration Index, Attributable Risk Percent, Population Attributable Risk Percent, Rate Ratio, and number of avoidable events (number of infant deaths).
Results: The average IMR (per 1 000 live births) according to the FDI strata were: stratum 1 (FDI = 0.41-0.52) = 18.8; stratum 2 (FDI = 0.53-0.55) = 17.9; stratum 3 (FDI = 0.56-0.58) = 15.0; and stratum 4 (FDI = 0.59-0.73) = 13.4. Overall, the Concentration Index was 0.02. Moreover, stratum 1, with a proportion of 17% of all live births in the population, had a concentration of 20% of infant deaths. Additionally, the profile of causes and ages of infant mortality also differed qualitatively when stratum 1 was compared to stratum 4.
Conclusions: The results suggest an association between the socioeconomic indicators, specifically the FDI, and the risk of infant death. These results call attention to the specific population groups in Brazil that are most vulnerable to infant mortality and demonstrate that the FDI can be used to identify these populations.