title: Fraction of exhaled nitric oxide in healthy Chilean schoolchildren aged 8-15 years.
abstract: BACKGROUND
  The fraction of exhaled nitric oxide (FENO) measured using portable devices is increasingly used in the clinical setting to assess asthmatic children. However, there is little and variable information on the reference values obtained using these devices in healthy children from different populations.
  
  
  METHODS
  190 healthy non-smoker children (8-15 years old) were randomly selected from public schools participating in this study. The objective was to determine FENO reference values for healthy Chilean schoolchildren. Healthy individuals were identified by medical interview and parent questionnaire on the use of asthma medications, and current and past symptoms of asthma, rhinoconjunctivitis and eczema. FENO was measured at schools using a portable device with electrochemical sensor (NIO MINOX). Reference values of FENO were expressed as geometric mean and upper limit of the 95% reference interval (right-sided). The relationship of FENO with gender, age, height, body mass, and other factors was assessed by multiple regression, and the difference between groups was contrasted by ANOVA.
  
  
  RESULTS
  The FENO geometric mean was 15.4ppb with a 95% reference interval upper limit (right-sided), of 27.4ppb (90%CI 25.6-29.2). The 5th and 95th percentiles were 9.0ppb and 28.0ppb, respectively. Height was the only factor significantly associated to FENO (p=0.022). There was no significant difference in mean FENO regarding age, gender, weight, parent reported rhinoconjunctivitis and eczema.
  
  
  CONCLUSIONS
  This study suggests that FENO values higher than 27ppb are likely to be abnormal and would reflect airway inflammation in children as those in the present study.
authors.affiliation: Department of Paediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Chile. Electronic address: jmallol@vtr.net.
authors.forename: J
authors.initials: J
authors.lastname: Mallol
authors.affiliation: Department of Paediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Chile.
authors.forename: V
authors.initials: V
authors.lastname: Aguirre
authors.affiliation: Department of Paediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Chile.
authors.forename: P
authors.initials: P
authors.lastname: Córdova
authors.affiliation: Department of Paediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Chile.
authors.forename: E
authors.initials: E
authors.lastname: Cortez
authors.affiliation: Department of Paediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Chile.
authors.forename: A
authors.initials: A
authors.lastname: Gallardo
authors.affiliation: Department of Paediatric Respiratory Medicine, Hospital El Pino, University of Santiago de Chile (USACH), Chile.
authors.forename: C
authors.initials: C
authors.lastname: Riquelme
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000175:diagnosis*; D001827:Body Height; D001944:Breath Tests / Q000379:methods*; D002648:Child; D002677:Chile; D004864:Equipment and Supplies; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011153:Population; D012016:Reference Values
chemical_list: D009569:Nitric Oxide
keywords: Asthma; Children; FENO; Reference values