1. Objectifs

Intentions :
«This study elucidates the importance of exposure timing, especially early prenatal and postnatal factors, on developing asthma in early years. […] we investigated the association between early environmental exposures occurring in the prenatal and postnatal period and the development of preschool (2 to 5 years of age) asthma. The objectives of the present study are (1) to assess the effect of early wheezing on subsequent development of asthma, after controlling for potential confounders, and (2) to examine the hygiene hypothesis by considering the factors that increase the likelihood of infections on development of asthma in early life.» (p. 7-8)

2. Méthode

Échantillon/Matériau :
Les auteurs utilisent les données récoltées auprès de 8940 enfants recensées par l’enquête suivante : «Canadian Early Childhood Development (ECD) cohort, conducted as part of the Canadian National Longitudinal Study of Children and Youth (NLSCY)». (p. 7)

Instruments:
Questionnaire

Type de traitement des données :
Analyse statistique

3. Résumé

«In our final multivariate analysis, early wheezing was identified as an independent risk factor for incidence of preschool asthma. It was associated with more than two times increased risk for developing asthma at preschool age. However, since not all wheezing infant and toddlers progress to develop asthma at a later age, the benefit of early interventions including drug therapy for wheeze among younger children, especially those who are under 3 years of age, is still unclear. […] The protective factors observed in this longitudinal study for the development of asthma are in line with a review of previous findings related to the hygiene hypothesis from cross-sectional studies. In particular, it was found that environmental factors that increase the likelihood for early infection in childhood such as daycare attendance, having more than one older sibling at birth, and not dwelling in urban centers have reduced the risk for developing asthma. […] In the current study, breastfeeding was a protective factor for the incidence of asthma. […] In conclusion, early wheezing during the first 2 years of life increased the risk for diagnosis of asthma in preschool years, independent of other risk factors. Although early environmental exposures are associated with incidence of asthma, hereditary factors cannot be ignored. To develop effective prevention strategies for the development of asthma in early childhood, mechanisms by which genetic and environmental factors may interact and result in protective or risk factors for the development of asthma need to be determined from future studies with lengthy follow-ups.» (p. 11-12)