RELATIONS OF BRONCHIAL RESPONSIVENESS TO ALLERGY SKIN-TEST REACTIVITY, LUNG-FUNCTION, RESPIRATORY SYMPTOMS, AND DIAGNOSES IN 13-YEAR-OLD NEW-ZEALAND CHILDREN

Background: Many factors have been found to relate univariately to bro nchial responsiveness (BR), but their independent relationships are of ten unclear because many are interrelated Objective: The purpose of th is study was to present a multivariate analysis of the closeness of th e association of various factors that are related univariately to BR, including allergy skin tests. Methods: The results of methacholine cha llenge were transformed into a continuous variable (BRindex), which ha s a nearly Gaussian distribution. With stepwise multiple regression, t he closeness of the association of the independent variables with BRin dex 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 I second to vital capacity and of perc ent 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. Concl usions: The size of the reactions to the four skin tests noted above s howed much closet correlations with BR than total serum IgE had shown at age 11, and the relationship was present in asthmatic and nonasthma tic subjects.