title: Lung function is abnormal in 3-month-old infants with cystic fibrosis diagnosed by newborn screening.
abstract: BACKGROUND
  Long-term benefits of newborn screening (NBS) for cystic fibrosis (CF) have been established with respect to nutritional status, but effects on pulmonary health remain unclear.
  
  
  OBJECTIVE
  With early diagnosis and commencement of standardised treatment, lung function at ∼3 months of age is normal in NBS infants with CF.
  
  
  METHODS
  Lung clearance index (LCI) and functional residual capacity (FRC) using multiple breath washout (MBW), plethysmographic (pleth) FRC and forced expirations from raised lung volumes were measured in 71 infants with CF (participants in the London CF Collaboration) and 54 contemporaneous healthy controls age ∼3 months.
  
  
  RESULTS
  Compared with controls, and after adjustment for body size and age, LCI, FRC(MBW) and FRC(pleth) were significantly higher in infants with CF (mean difference (95% CI): 0.5 (0.1 to 0.9), p=0.02; 0.4 (0.1 to 0.7), p=0.02 and 0.9 (0.4 to 1.3), p<0.001, z-scores, respectively), while forced expiratory volume (FEV(0.5)) and flows (FEF(25-75)) were significantly lower (-0.9 (-1.3 to -0.6), p<0.001 and -0.7 (-1.1 to -0.2), p=0.004, z-scores, respectively). 21% (15/70) of infants with CF had an elevated LCI (>1.96 z-scores) and 25% (17/68) an abnormally low FEV(0.5) (below -1.96 z-scores). While only eight infants with CF had abnormalities of LCI and FEV(0.5), using both techniques identified abnormalities in 35% (24/68). Hyperinflation (FRC(pleth) >1.96 z-scores) was identified in 18% (10/56) of infants with CF and was significantly correlated with diminished FEF(25-75) (r=-0.43, p<0.001) but not with LCI or FEV(0.5).
  
  
  CONCLUSIONS
  Despite early diagnosis of CF by NBS and protocol-driven treatment in specialist centres, abnormal lung function, with increased ventilation inhomogeneity and hyperinflation and diminished airway function, is evident in many infants with CF diagnosed through NBS by 3 months of age.
authors: Respiratory Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK. a.hoo@ucl.ac.uk
authors: Ah-Fong
authors: AF
authors: Hoo
authors: Lena P
authors: LP
authors: Thia
authors: The Thanh Diem
authors: TT
authors: Nguyen
authors: Andrew
authors: A
authors: Bush
authors: Jane
authors: J
authors: Chudleigh
authors: Sooky
authors: S
authors: Lum
authors: Deeba
authors: D
authors: Ahmed
authors: Ian
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authors: Balfour Lynn
authors: Siobhan B
authors: SB
authors: Carr
authors: Richard J
authors: RJ
authors: Chavasse
authors: Kate L
authors: KL
authors: Costeloe
authors: John
authors: J
authors: Price
authors: Anu
authors: A
authors: Shankar
authors: Colin
authors: C
authors: Wallis
authors: Hilary A
authors: HA
authors: Wyatt
authors: Angela
authors: A
authors: Wade
authors: Janet
authors: J
authors: Stocks
mesh_terms: D000886:Anthropometry; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000503:physiopathology*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008131:London; D008137:Longitudinal Studies; D008297:Male; D015997:Neonatal Screening; D010991:Plethysmography; D011379:Prognosis; D012129:Respiratory Function Tests