Risk factors for acute respiratory disease hospitalization in children under one year of age

OBJECTIVE: To evaluate risk factors for acute respiratory disease hospitalizations in children under one year of age. METHODS: A case-control study was conducted in the city of Pelotas, Southern Brazil. Cases were children under one year of age who were hospitalized due to acute respiratory diseases from August 1997 to July 1998. Controls were same-age community children randomly selected without previous respiratory disease hospitalization. A questionnaire about risk factors exposure was applied to the mothers of cases and controls. Univariate, bivariate and multivariate analyses through logistic regression were carried out to evaluate risk factors for the outcome of interest. RESULTS: There were studied 777 children; 625 cases and 152 controls. In the crude analysis, the risk factors associated with the outcome were: being male, children under six months of age, household crowding, maternal education, family income, inadequate housing conditions, lack of breastfeeding, maternal smoking, use of pacifiers, and a previous history of hospitalization and respiratory symptoms. Maternal working was a protection factor associated with acute respiratory disease hospitalizations. In the multivariate analysis the following risk factors remained associated: maternal education (OR=12.5), previous history of wheezing (OR=7.7), lack of breastfeeding (OR=2.3), use of pacifiers (OR=1.9), maternal smoking (OR=1.7), children under six months of age (OR=1.7), and being male (OR=1.5). CONCLUSIONS: The study results show the importance of the family's social and behavioural aspects as well as previous respiratory disease as risk factors for acute respiratory disease hospitalizations in children under one year of age.