Variations in infant mortality rates among municipalities in the state of Ceara, northeast Brazil: an ecological analysis

Background Infant mortality rates vary substantially among municipalities i n the State of Ceara from 14 to 193 per 1000 live births. Identification of the determinants of these differences can be of particular importance to i nfant health policy and programmes in Brazil where local governments play a pivotal role in providing primary health care. Methods Ecological study across 140 municipalities in the State of Ceara, B razil. Results To determine the interrelationships between potential predictors of infant mortality, we classified 11 variables into proximate determinants ( adequate weight gain and exclusively breastfeeding), health services variab les (prenatal care up-to-date, participation in growth monitoring, immuniza tion up-to-date, and decentralization of health services), and socioeconomi c factors (female literacy rate, household income, adequate water supply, a dequate sanitation, and per capita gross municipality product), and include d the variables in each group simultaneously in linear regression models. I n these analyses, only one of the proximate determinants (exclusively breas tfeeding (inversely), R-2 = 9.3) and one of the health services variables ( prenatal care up-to-date (inversely), R-2 = 22.8) remained significantly as sociated with infant mortality. In contrast, female literacy rate (inversel y), household income (directly) and per capita GMP (inversely) were indepen dently associated with the infant mortality rate (for the model including t he three variables R-2 = 25.2). Finally, we considered simultaneously the v ariables from each group, and selected a model that explained 41% of the va riation in infant mortality rates between municipalities. The paradoxical d irect association between household income and infant mortality was present only in models including female illiteracy rate, and suggests that among t hese municipalities, increases in income unaccompanied by improvements in f emale education may not substantially reduce infant mortality. The lack of independent associations between inadequate sanitation and infant mortality rates may be due to the uniformly poor level of this indicator across muni cipalities and provides no evidence against its critical role in child surv ival. Conclusions These results suggest that promotion of exclusive breastfeeding and increased prenatal care utilization, as well as investments in female education would have substantial positive effects in further reducing infan t mortality rates in the State of Ceara.