Bronchial hyperresponsiveness in two populations of South Australian rural schoolchildren

This report describes the cross-sectional analyses of the results obtained from the first year of a longitudinal study designed to investigate the natural history of bronchial hyperresponsiveness in association with reported respiratory symptoms in children attending the Burra and Kingston Community Schools. Bronchial hyperresponsiveness to methacholine was measured using a modified Yan technique. Prevalence rates of respiratory symptoms were obtained using the Tasmanian Asthma Foundation Questionnaire. Considerable overlap of reported symptoms of asthma and/or wheezy breathing and bronchitis and/or loose and productive cough was observed suggesting that a clear distinction between such symptoms in childhood may not be possible. Analyses of data showed the prevalence of reactive airways in children to be 21.3% in Burra and 22.0% in Kingston. These values were the same as results obtained from an earlier pilot study in Burra and similar to results from Wagga Wagga (19.6%) and Auckland (20.1%) but higher than from Belmont (15.5%) and Villawood (15.3%). Increased bronchial hyperresponsiveness was associated with the reporting of symptoms of asthma and/or wheezy breathing (odds ratio, 5.04; 95% confidence interval, 2.18-11.74) and bronchitis and/or loose and productive cough (odds ratio, 2.28; 95% confidence interval, 1.02-5.13), at any time in the child's life. Of children with no reported symptoms 10% also had demonstrable bronchial hyperresponsiveness.