Methods: Cross-sectional study using a standardized and validated questionnaire (EISL: Estudio Internacional sobre Sibilancias en Lactantes) with questions: Has your baby had wheezing or whistling in the chest area or bronchitis in the first 12 months of life? Has your baby had 3 or more wheezing episodes in the first year of life? Parents of infants, ages 12-15 months that attended to Health Centers for routine immunization were interviewed between August/2005 to December/2006 (EISL Phase I) and September/2009 to September/2010 (EISL Phase III). Categorical variables are shown as proportion and differences verified by chi-square test, and continuous variables were expressed as mean±SD and analyzed by Student t test.
Results: Three thousand and three parents of infants answered questionnaire in the EISL Phase I, and 45.4% had had at least one wheezing episode; 50.7% were male, and 22.6% had recurrent wheezing episode starting at 5.5±3.1 months. Five years later, in the EISL Phase III, one thousand and three parents participated in the survey: 40.6% had at least one wheezing episode (p=0.46), 51.1% were male, and 19.8% had recurrent wheezing (p=0.1) starting at 6.1±3 months (p=0.06).
Conclusions: Recurrent wheezing in infancy is highly prevalent and starts early in life. In our population, recurrent wheezing rates did not modify in the time period of study.