title: Ethnic differences in fraction of exhaled nitric oxide and lung function in healthy young children.
abstract: BACKGROUND
  Ethnic differences in lung function in school-aged children and adults are well recognized, but little is known about such differences in preschool children. We investigated whether differences exist in fraction of exhaled nitric oxide (Feno), multiple-breath washout (MBW) indices, specific airways resistance (sRaw), and spirometry indices between healthy preschool children of South Asian and white European origin.
  
  
  METHODS
  Feno, MBW indices (lung clearance index, functional residual capacity, conductive airways inhomogeneity, and acinar airways inhomogeneity), sRaw, and spirometry were measured in healthy South Asian and white children aged 4 to 6 years, and comparisons were made between the two groups. Statistical analyses were by multiple linear regression and t tests.
  
  
  RESULTS
  Thirty-seven white (mean age 5.8 ± 0.7 years, 49% boys) and 31 South Asian children (mean age 5.4 ± 0.8 years, 52% boys) were recruited. Feno was, on average, 36% higher (P < .05) in South Asian children compared with white children. FVC and FEV(1) and fractions thereof (FEV(0.75) and FEV(0.5)) z-scores were significantly lower in South Asian compared with white children by 0.69 (P = .01), 0.76 (P = .004), 0.76 (P = .009), and 0.85 (P = .002) z-scores, respectively, but there were no significant differences in FEV(1)/FVC, FEF(25-75), sRaw, or MBW indices.
  
  
  CONCLUSIONS
  Differences in Feno and forced expiratory lung volumes between South Asian and white children exist from a very young age. Ethnic differences should be taken into account when interpreting lung function results in preschool children for effective management of respiratory conditions.
authors.affiliation: Portex Unit: Respiratory Medicine and Physiology, University College London Institute of Child Health; Department of Paediatric Respiratory Medicine, Great Ormond Street Hospital for Children NHS Trust. Electronic address: s.sonnappa@ich.ucl.ac.uk.
authors.forename: Samatha
authors.initials: S
authors.lastname: Sonnappa
authors.affiliation: Portex Unit: Respiratory Medicine and Physiology, University College London Institute of Child Health.
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Bastardo
authors.affiliation: Department of Paediatric Respiratory Medicine, Great Ormond Street Hospital for Children NHS Trust.
authors.forename: Patrick
authors.initials: P
authors.lastname: Stafler
authors.affiliation: Department of Paediatric Respiratory Medicine, Royal Brompton Hospital and Imperial College, Sydney Street, London, England.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bush
authors.affiliation: Portex Unit: Respiratory Medicine and Physiology, University College London Institute of Child Health; Department of Paediatric Respiratory Medicine, Great Ormond Street Hospital for Children NHS Trust.
authors.forename: Paul
authors.initials: P
authors.lastname: Aurora
authors.affiliation: Portex Unit: Respiratory Medicine and Physiology, University College London Institute of Child Health.
authors.forename: Janet
authors.initials: J
authors.lastname: Stocks
mesh_terms: D044466:Asian People / Q000706:statistics & numerical data*; D016009:Chi-Square Distribution; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D045853:Exhalation; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D012129:Respiratory Function Tests / Q000379:methods*; D044465:White People / Q000706:statistics & numerical data*
chemical_list: D009569:Nitric Oxide