Fig. 2. Exploratory factor analysis based on principal component analysis and multiple correspondence analysis. The first and second principal components accounted for 21.9% and 15.6% of the total variance, respectively. (A) Cluster variables including age, type 2 inflammatory markers, parameters for bronchial hyper-responsiveness, and sensitization to allergens against the first 2 principal components. Arrows are displayed for cluster variables against the first 2 principal components. (B) Individual patients were categorized by the cluster against first 2 principal components. The dots are displayed for individual patients, and they are divided into 4 colors based on the cluster.

FAMD, factor analysis of mixed data; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; PC20, provocative concentration < 16 mg/mL that caused a 20% decrease in forced expiratory volume in one second; IgE, immunoglobulin E; HDM, house dust mite.