Increased risk of school age asthma following multiple trigger wheeze, independent of atopy

Background: Multiple trigger wheeze (MTW) i.e. wheezing also apart from colds has been associated with an increased risk of later asthma compared to episodic viral wheeze (EVW) i.e . wheezing with colds only. However, the predictive value of these phenotypes has been questioned. The aim of this study was to analyse the risk of school age asthma in preschool children with MTW vs EVW. Methods: Data were obtained from a prospective, longitudinal study of a cohort of children born in western Sweden. The parents answered questionnaires at 6 months and 1, 4.5 and 8 years of age. The response rate at 8 years was 80% of the questionnaires distributed (4,051/5,044), i.e. 71% of the families entering the study (4,051/5,654). Results: The prevalence of doctor-diagnosed asthma at 8 years was 67% in children with MTW and 33 % in children with EVW. The risk of asthma was increased both in children with MTW (OR 48.9, CI 95% 29.3-81.6) and EVW (OR 16.2, 10.3-25.6) compared to no wheeze at age 4.5 and in MTW vs EVW (OR 3.4, 1.8-6.5), independent of atopic heredity and other allergic manifestations at preschool age. The increased risk of asthma in MTW vs EVW, was evident also when analysing only subjects without allergy at preschool age (OR 3.6, 1.8-7.1). In children with MTW, atopic asthma was more common and both the risk of atopic asthma (OR 6.2, 3.1-12.7) and non-atopic asthma (OR 2.3, 1.03-4.9) was higher vs EVW. Conclusion: The risk of doctor-diagnosed asthma at 8 years was increased among preschool children with MTW vs EVW, independent of heredity and preschool allergy, and also in children without preschool allergy. In addition, atopic asthma at 8 years was more common among children with MTW.