A positive family history with prevalence of atopy, eczema, wheezing are well-known factors predicting asthma. Caudri et al. found more important predictors like perinatal transmission, parental use of inhalative medications and wheezing/dyspnea out of viral infections(5). Measurement of BHR in children was in most studies a second outcome parameter.
Four visits will be performed, baseline and after 1, 3, and 5 years. At visit 1 the investigators will characterize all patients by a ISAAC survey. At each visit in children a methacholine challenge, a skin Prick test, eNO, RAST and total IgE will be performed. At visit 3 and 4 sputum will be induced. In parents only at the first visit a methacholine challenge will be performed. A genetic identification of ADAM33 gene from EDTA blood shall be provided. ADAMs are multidomain proteins with a metalloprotease domain, associated with airway remodelling. Visits should be kept in a time interval without asthma therapy and respiratory infection.
To examine the feasibility of methacholine challenges in preschool children data measured in 2006 will be analysed.
