title: Endothelial function in children with OSA and the effects of adenotonsillectomy.
abstract: BACKGROUND
  The association between childhood OSA and endothelial function as measured by flow-mediated dilation (FMD) and its response to OSA treatment are uncertain. The objective of this study was to compare FMD in children with OSA with nonsnoring control subjects and to examine its response to treatment.
  
  
  METHODS
  Index cases were children aged 6 to 18 years with habitual snoring and polysomnography (PSG)-confirmed OSA (obstructive apnea hypopnea index [OAHI] > 1 events/h). Each case was paired with an age-, sex-, and BMI-matched nonsnoring control subject recruited from our previous community growth survey. All subjects underwent FMD measurement in the morning after overnight PSG. Adenotonsillectomy (AT) was offered to subjects who satisfied predefined AT operation criteria. All cases underwent repeat PSG and FMD assessment 6 months later.
  
  
  RESULTS
  A total of 63 case-control pairs were recruited. The OSA group had a significantly higher OAHI (median, 5.3 events/h [interquartile range (IQR), 2.6-11.7] vs 0.2 events/h [IQR, 0-0.5], P < .001) and lower FMD (mean ± SD, 7.9% ± 1.3% vs 8.3% ± 0.8%; P = .04) than the control group. Thirty-two case subjects underwent AT. A significant reduction in OAHI was documented in the AT group (-8.8 events/h [IQR, -13.7 to -4.7]; P < .001) accompanied by a significant increase in FMD (+0.6% [IQR, 0.4-1.4]; P < .001), which was not observed in subjects who did not undergo AT.
  
  
  CONCLUSIONS
  Children with OSA had reduced FMD, which was reversible with treatment.
authors.affiliation: Department of Pediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Kate C C
authors.initials: KCC
authors.lastname: Chan
authors.affiliation: Department of Pediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Chun T
authors.initials: CT
authors.lastname: Au
authors.affiliation: Department of Pediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Ping
authors.initials: P
authors.lastname: Chook
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Dennis L Y
authors.initials: DLY
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Hugh S
authors.initials: HS
authors.lastname: Lam
authors.affiliation: Department of Psychiatry, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Yun K
authors.initials: YK
authors.lastname: Wing
authors.affiliation: Department of Pediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong. Electronic address: albertmli@cuhk.edu.hk.
authors.forename: Albert Martin
authors.initials: AM
authors.lastname: Li
mesh_terms: D000233:Adenoidectomy; D000293:Adolescent; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D002648:Child; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000601:surgery; D014068:Tonsillectomy; D014463:Ultrasonography; D014664:Vasodilation / Q000502:physiology*