Leprosy in Brazil and its association with characteristics of municipalities: ecological study, 2009-2011

Objective To analyse the ecological association between the demographic and socio-economic characteristics of the Brazilian municipalities and average leprosy incidence rate in the period 2009–2011. Methods An ecological study taking the Brazilian municipalities as its units of analysis. The local empirical Bayes estimation method was used to obtain smoothed incidence rates (SIR) for leprosy. The mean, median, first quartile (Q1) and third quartile (Q3) of the SIR were calculated per 100 000 inhabitants. Hierarchical log-linear negative binomial regression models were used to estimate the incidence rate ratios (IRR). Results In the period 2009–2011, the average SIR of leprosy in Brazil was 20.2 per 100 000 inhabitants, and the median incidence rate among municipalities was 9.1 per 100 000 inhabitants. Significantly higher adjusted IRR were identified for large municipalities (IRR = 1.67) compared to small municipalities, as well as in municipalities with higher illiteracy rates (IRR = 2.15), more urbanised municipalities (IRR = 1.53), those with greater social inequality as per the Gini index (IRR = 1.26), high percentage of households with inadequate sanitation (IRR = 1.63), higher average number of people per room (IRR = 1.41), high proportions of Family Health Programme coverage (IRR = 1.29), high percentage of household contacts investigated (IRR = 2.30) and those with percentage of cases with grade 2 disability considered to be the medium (IRR = 1.26). Conclusions In this study, SIR was significantly associated with municipalities with low socio-economic status. Disease control activities need to be focused on these municipalities, and investments need to be made in improving the population's living conditions.