Relations of bronchial responsiveness to allergy skin test reactivity, lung function, respiratory symptoms, and diagnoses in thirteen-year-old New Zealand children

BACKGROUND: Many factors have been found to relate univariately to bronchial responsiveness (BR), but their independent relationships are often unclear because many are interrelated. OBJECTIVE: The purpose of this study was to present a multivariate analysis of the closeness of the association of various factors that are related univariately to BR, including allergy skin tests. METHODS: The results of methacholine challenge were transformed into a continuous variable (BRindex), which has a nearly Gaussian distribution. With stepwise multiple regression, the closeness of the association of the independent variables with BRindex was evaluated. RESULTS: Of the 11 skin tests applied, four showed independent relationships to BRindex (mite, cat, dog, and Aspergillus species). The sizes of these skin test reactions were correlated with BRindex, and their sum appeared to maximize the overall correlation of allergy skin tests with BRindex (r = 0.516). The lowness of the ratio of forced expiratory volume in 1 second to vital capacity and of percent predicted forced expiratory volume in 1 second added significantly to the skin tests in correlating with BRindex, (multiple r = 0.621). Adding diagnoses and symptoms increased the multiple r to 0.685. CONCLUSIONS: The size of the reactions to the four skin tests noted above showed much closer correlations with BR than total serum IgE had shown at age 11, and the relationship was present in asthmatic and nonasthmatic subjects.