According to the World Health Organisation, community-acquired pneumonia is the main cause of paediatric death, accounting for 20 % of deaths in children younger than 5 years old, and 90 % of these deaths occur in non-industrialised countries. This study has as objective to evaluate the influence of socio-economic, environmental and breastfeeding factors on the occurrence of pneumonia. An unmatched case-control study was conducted in children aged 6 months to 13 years old at a children's hospital in Brazil. Multivariate analysis by logistic regression was performed to determine the variables used to predict pneumonia. A total of 252 children were selected. In the adjusted (by age) multivariate analysis, the following variables were associated with community-acquired pneumonia: (a) protective factors: breastfeeding >3 months, absence of other unrelated comorbidities, non-smoking mother, being the only child, child's age >5 years and mother's age >19 years old; (b) risk factors: maternal education <8 years and child's birth order [≥second]. In the multivariate analysis, considering only children from 6 months to 5 years old, the following variables were associated with community-acquired pneumonia: (a) protective factors: breastfeeding >3 months, non-smoking mother and no smokers in the child's bedroom; (b) risk factors: maternal education <8 years and prenatal complications.
Conclusion: These findings contribute favourably to effectively minimising the risk factors related to the disease process and natural history of community-acquired pneumonia.