Univariate analysis of factors associated with PD100 sRaw values at 9 years of age.

Data were analyzed with all children, and after exclusion of non responders to methacholine challenge. Severe exacerbations were defined as the need for oral steroids or an emergency visit. Parental atopy was defined by a diagnosis of asthma or allergic rhinitis in the mother or father. Linear regression was used to compare continuous variables, and analysis of variance to compare groups. * significance in post-hoc analysis.