Methods: This is a cross-sectional study using standardized and validated questionnaire (EISL: Estudio Internacional sobre Sibilancias en Lactantes). Parents of infants, aged 12-15 months who attended to Health Centers for routine immunization were interviewed. This international, population-based study, compares data from two surveys (S1 in 2005 and S2 in 2012) conducted in three large cities that participated in both surveys: Curitiba and São Paulo (Brazil) and Santiago (Chile).
Results: There was a significant decrease in the mean prevalence of RW during the first year of life between S1 (23.3%, 95% CI 22.3-24.3) and S2 (20.4%, 95%CI 19.0-21.8), p=0.004. In infants with RW the mean prevalence of severity markers between S1 and S2 remained high (severe episode: 56.9% to 54.2%, p=0.32); Emergency Department (ED) visits (68.1% to 70.9 %, p=0.21), with significant increase in admissions for wheezing (21.1% to 26.7%, p=0.004). Significant increase in the use of inhaled corticosteroids (1.7 and 2.9-fold) and leukotriene modifiers (5.1 and 5.3-fold) in Curitiba and São Paulo, respectively. This was concomitant to a significant increase in the prevalence of physician-diagnosed asthma between S1 and S2.
Conclusions: RW infants have higher prevalence of severity markers such as visits to ED and admissions for wheezing. There has been increased use of asthma medications in Brazilian children, relating to higher prevalence of physician-diagnosed asthma.