Association of age with AHR
In this study we found a negative association between age at time of diagnosis and presence of AHR. Also, in multivariate analysis, age remained a strong predictor of AHR. Our results were in accordance with several studies that report a relationship between age and AHR in children(14, 34, 37). But the relationship with age seems to be multifaceted. Obviously pathophysiologic processes determining AHR alter with age(33) as well as with the duration of disease(38), and the predictive value of some variables changes depending on age(14). An additional influence of age might be due to the considerable growth rate of children leading to the application of a larger dose in young children related to body size(34).