ABSTRACT
OBJECTIVE: The hygiene hypothesis postulates that infections early in life might influence the development of asthma later in childhood. However, this hypothesis is controversial. The objective of this study was to determine whether there is a relationship between infection-related risk factors during infancy and development of asthma later in childhood. METHODS: Data were obtained by a nationwide, population-based, cross-sectional study of 26,400 children, 7 to 12 years of age. Parents completed a questionnaire on symptoms of and risk factors for asthma, including the number of fever episodes, acute gastroenteritis, use of antibiotics, and immunization during infancy. The presence of asthma was defined by parental report of "wheeze in the last 12 months" or "asthma ever." Data were analyzed by logistic regression analysis. RESULTS: The occurrence of fever during infancy was weakly associated with the development of asthma (P < 0.05). A higher frequency of episodes of fever was associated with a higher risk of development of asthma. The relationship between antibiotic use during infancy and development of asthma was also significant (P < 0.0001). The adjusted odds ratios of childhood asthma increased in proportion to the number of antibiotic courses during infancy. A history of acute gastroenteritis during infancy increased the risk of developing asthma in later life (P < 0.001). In contrast, immunization in infancy was not related to development of asthma in childhood (P > 0.05). CONCLUSIONS: These data suggest that the development of childhood asthma is associated with episodes of fever, antibiotic use, and acute gastroenteritis during infancy.
