Page 13 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

Figure 1. Incidence of asthma stratified per age category. Adapted from De Marco et al.11
ADULT-ONSET ASTHMA, A HETEROGENEOUS DISEASE
Asthma phenotypes
Adult-onset asthma is a heterogeneous disease with a variable clinical picture and a complex pathophysiology.10, 28 Therefore the term adult-onset asthma can be regarded as an umbrella term for several distinct airway diseases, so called asthma phenotypes.29 Early day phenotyping of asthma was based on clinical recognition of subtypes6, 23, 30 and more recently an integrative statistical approach using cluster analysis has shown a wide variety of asthma-phenotypes.8, 31 These phenotypes can be based on several aspects of the disease, most used are either clinical and physiological features, asthma triggers or airway inflammation type.28, 32 Well known clinical phenotypes are for instance obesity associated asthma,31 asthma with chronic sinusitis and nasal polyps,33 cough-variant asthma,34 asthma with persistent airflow limitation35 and asthma with frequent exacerbations36; trigger associated phenotypes like occupational asthma,17 smoking related asthma,37 atopic or non-atopic asthma38, 39 and finally inflammatory phenotypes such as eosinophilic
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GENERAL INTRODUCTION AND AIMS
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