Asthma occurrence in children and early life systemic antibiotic use: an incidence density study.

Background: Results of studies evaluating the relationship between asthma occurrence and early life antibiotic use have been conflicting. The aim of this study was to investigate the relationship between occurrence of asthma in children and systemic antibiotic use in the first year of life based on an incidence density study with careful consideration of the temporal aspects of the determinant-outcome relationship.

Methods: We conducted an incidence density study nested in a data collection project with information on 1128 mother-child pairs.