title: Phenotypic analysis of asthma in Japanese athletes.
abstract: BACKGROUND
  Asthma in athlete populations such as Olympic athletes has various pathogeneses. However, few reports are available on the features of asthma in the athlete population in clinical practice. In this study, we focused on classifying asthma in Japanese athlete population.
  
  
  METHODS
  We performed a cluster analysis of data from pulmonary function tests and clinical biomarkers before administering inhaled corticosteroids (ICS) therapy in athlete population of individuals diagnosed with asthma (n = 104; male, 76.9%; median age, 16.0 years), based on respiratory symptoms and positive data on methacholine provocation tests. We also compared backgrounds, sports types, and treatments between clusters.
  
  
  RESULTS
  Three clusters were identified. Cluster 1 (32%) comprised athletes with a less atopic phenotype and normal pulmonary function. Cluster 2 (44%) comprised athletes with a less atopic phenotype and lower percent predicted forced expiratory volume in 1 s (%FEV1) values, despite less symptomatic state. Cluster 3 (24%) comprised athletes with a strong atopic phenotype such as high eosinophil count in the blood and total serum immunoglobulin E level. After treatment with ICS or ICS plus long-acting β-adrenergic receptor agonist for 6-12 months, %FEV1values were significantly improved in Cluster 2 athletes, whereas Cluster 3 athletes had a significant decrease in the fraction of exhaled nitric oxide compared to pretreatment values.
  
  
  CONCLUSIONS
  These data suggest three clusters exist in Japanese athlete population with asthma. Between the clusters, the characteristics differed with regard to symptoms, atopic features, and lower %FEV1values. The pathogeneses between clusters may vary depending on the inflammation type and airway hyperresponsiveness.
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tsukioka
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. Electronic address: tkoya@med.niigata-u.ac.jp.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Koya
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueno
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Masachika
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Sakagami
authors.affiliation: Department of General Medicine, Niigata University Medical and Dental Hospital, Niigata, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Niigata Institute for Health and Sports Medicine, Niigata, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Arakawa
authors.affiliation: Department of General Medicine, Niigata University Medical and Dental Hospital, Niigata, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Suzuki
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kikuchi
mesh_terms: D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D056352:Athletes; D015415:Biomarkers; D001985:Bronchial Provocation Tests; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007564:Japan / Q000453:epidemiology; D007958:Leukocyte Count; D008297:Male; D009569:Nitric Oxide / Q000032:analysis; D010641:Phenotype; D013177:Sports; D063189:Symptom Assessment; D016896:Treatment Outcome
chemical_list: D018927:Anti-Asthmatic Agents; D015415:Biomarkers; D009569:Nitric Oxide; D007073:Immunoglobulin E
keywords: Asthma; Athlete; Cluster analysis; Fraction of exhaled nitric oxide; Methacholine provocation test