Validation of questions on asthma and wheeze in farming and anthroposophic children


  • PARSIFAL study group: Göran Pershagen, Tobias Alfvén, Johan Alm, Anna Bergström, Lars Engstrand, Helen Flöistrup, Marianne van Hage-Hamsten, Niclas Håkansson, Gunnar Lilja, Fredrik Nyberg, Annika Scheynius, Helena Svensson, Jackie Swartz, Magnus Wickman (Sweden); Charlotte Braun-Fahrländer, Marco Waser, Felix Sennhauser, Roger Lauener, Johannes Wildhaber, Alex Möller (Switzerland); Bert Brunekreef, Dieneke Schram, Gert Doekes, Mirian Boeve, Jeroen Douwes, Machteld Huber, Mirjam Matze (the Netherlands); Erika von Mutius, Rob van Strien, Marcus R. Benz, Jörg Budde, Markus Ege (Germany); Josef Riedler, Waltraud Eder, Ellen Üblagger, Gertraud Weiss, Mynda Schreuer (Austria), Karin B. Michels (USA).

Ellen Üblagger, Children's Hospital, Department of Paediatric Pulmonology, Müllner Hauptstraße 48, A-5020 Salzburg, Austria.


Background In most epidemiological surveys the estimated prevalence of asthma is based on questionnaire responses, which may depend on the individual's perception as well as medical consulting habits in a given population. Therefore, measurement of bronchial hyper-responsiveness as a key feature of asthma has been suggested as an objective parameter for asthma.

Objective The aim of the present study was to validate questionnaire responses on asthma and wheeze against bronchial response to hypertonic saline (HS) (4.5%) in populations previously shown to have a lower prevalence of asthma and allergies: farmers' children and children from anthroposophic families.

Methods Children whose parents had completed a written questionnaire in the cross-sectional PARSIFAL-study were drawn from the following four subgroups: ‘farm children’ (n=183), ‘farm reference children’ (n=173), ‘Steiner schoolchildren’ (n=243) and ‘Steiner reference children’ (n=179). Overall, 319 children with wheeze in the last 12 months and 459 children without wheeze in the last 12 months performed an HS challenge.

Results Odds ratios, sensitivity, specificity, likelihood ratios and measures of association did not differ significantly between the four subgroups. The correlation between the bronchial response to HS and wheeze and asthma questions was moderate and similar for farm children, farm reference children, Steiner schoolchildren and Steiner reference children (κ for ‘wheeze’: 0.25, 0.33, 0.31, 0.35, respectively, P=0.754, κ for ‘doctor's diagnosis of asthma’: 0.33, 0.19, 0.33, 032, respectively, P=0.499).

Conclusion The findings from this study suggest that the reliabilitiy of questionnaire responses on asthma and wheeze is comparable between farmers' children, children raised in families with anthroposophic lifestyle and their respective peers.