title: Asthma phenotypes identified by latent class analysis in the ISAAC phase II Spain study.
abstract: BACKGROUND
  Classification of respiratory symptoms may help to identify different underlying asthma phenotypes reflecting differences in aetiology and prognosis of wheezing disease among children.
  
  
  OBJECTIVE
  To determine childhood asthma phenotypes based on respiratory symptoms from a widely used questionnaire to further classify phenotypes in international settings.
  
  
  METHODS
  Between 2000 and 2002 cross-sectional studies were performed in four centres in Spain. Parental questionnaires were used to collect information on allergic diseases in more than 4000 children aged 8-12 years. In addition, objective markers for allergic sensitization and bronchial hyperresponsiveness (BHR) were measured. Latent class analyses (LCA) were applied to identify subgroups of children according to respiratory symptoms, and then the association of these groups with relevant clinical features such as concomitant allergic disease symptoms, atopy and BHR was studied.
  
  
  RESULTS
  We found seven classes, one corresponding to healthy children, three classes related to wheeze and three other classes mainly related to congestion and coughed-up phlegm. These tentative phenotypes differed in severity of symptoms and also in clinical correlates such as BHR and allergic sensitization. Atopy was more predominant in the 'wheeze phenotypes' whereas concomitant 'allergic' symptoms were most frequent in two of the 'wheeze phenotypes' and one of the 'cough phenotypes'.
  
  
  CONCLUSIONS
  LCA on reported symptoms in a cross-sectional survey allowed different subgroups with meaningful clinical correlates to be defined. It remains to be investigated to what extent these groups also have different aetiologies, prognoses and therapeutic needs.
authors: Institute of Epidemiology and Medical Biometry, Ulm University, 89081 Ulm, Germany. gudrun.weinmayr@uni-ulm.de
authors: G
authors: G
authors: Weinmayr
authors: F
authors: F
authors: Keller
authors: A
authors: A
authors: Kleiner
authors: J B
authors: JB
authors: du Prel
authors: L
authors: L
authors: Garcia-Marcos
authors: J
authors: J
authors: Batllés-Garrido
authors: G
authors: G
authors: Garcia-Hernandez
authors: M M
authors: MM
authors: Suarez-Varela
authors: D P
authors: DP
authors: Strachan
authors: G
authors: G
authors: Nagel
mesh_terms: D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010641:Phenotype; D012135:Respiratory Sounds / Q000175:diagnosis* / Q000187:drug effects / Q000209:etiology; D012307:Risk Factors; D013030:Spain; D011795:Surveys and Questionnaires
chemical_list: D018927:Anti-Asthmatic Agents