title: Induced sputum inflammatory measures correlate with disease severity in children with obstructive sleep apnoea.
abstract: OBJECTIVE
  To establish the association between airway inflammation and severity of obstructive sleep apnoea (OSA) in children.
  
  
  METHODS
  Consecutive children presenting with symptoms suggestive of OSA were recruited. They completed a sleep apnoea symptom questionnaire, underwent physical examination, spirometry, sputum induction and an overnight polysomnography. Adequate sputum contained <50% squamous epithelial cells, and OSA was diagnosed if the obstructive apnoea index was >1.
  
  
  RESULTS
  73 children with a median (interquartile range (IQR)) age of 11.3 (10.0-13.2) years were recruited. There were 21 girls and the median body mass index of the group was 24.0 (18.0-27.0) kg/m2. The most common presenting symptoms were habitual snoring, mouth breathing and prone sleeping position. Sputum induction was successful in 43 (59%) children, of whom 14 were found to have OSA. Children with OSA had significantly greater percentage sputum neutrophil than those without OSA (18.5 (IQR 8.0-42.0) v 4 (IQR 3.0-11.3), p = 0.006). On multiple regression analysis, percentage sputum neutrophil was significantly associated with OSA (odds ratio = 1.1, p = 0.013).
  
  
  CONCLUSIONS
  Children with OSA had airway inflammation characterised by a marked increase in neutrophils. Further studies are needed to confirm these findings and to better define the downstream cellular interactions and molecular pathogenesis in childhood OSA.
authors.affiliation: Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong SAR. albertmli@cuhk.edu.hk
authors.forename: A M
authors.initials: AM
authors.lastname: Li
authors.forename: E
authors.initials: E
authors.lastname: Hung
authors.forename: T
authors.initials: T
authors.lastname: Tsang
authors.forename: J
authors.initials: J
authors.lastname: Yin
authors.forename: H K
authors.initials: HK
authors.lastname: So
authors.forename: E
authors.initials: E
authors.lastname: Wong
authors.forename: T F
authors.initials: TF
authors.lastname: Fok
authors.forename: P C
authors.initials: PC
authors.lastname: Ng
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D012044:Regression Analysis; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012913:Snoring / Q000209:etiology; D013183:Sputum / Q000737:chemistry*