title: Analysis of the associations between lung function and clinical features in preschool children with cystic fibrosis.
abstract: OBJECTIVE
  To analyze cross-sectional and longitudinal associations between lung function measures and clinical features in a cohort of preschool children with cystic fibrosis (CF).
  
  
  METHODS
  Longitudinal eight-center observational study of children with CF aged 36-60 months at enrollment, who underwent semiannual pulmonary function tests (PFTs) for up to 2 years consisting of spirometry (all 8 sites), forced oscillometry (FO, 5 sites), and measures of thoracoabdominal asynchrony using respiratory inductive plethysmography (IP, 5 sites).
  
  
  RESULTS
  Ninety-three subjects were enrolled; 181 acceptable spirometry measurements from 71 subjects, 128 FO from 47 subjects, and 142 IP from 50 subjects were available for analysis. Cross sectional analyses did not detect an association between any PFT parameter at enrollment and Pseudomonas aeruginosa (Pa) status, CF gene mutation class, Wisconsin cough score, Shwachman score, environmental tobacco smoke exposure, family history of asthma, or nutritional indices. In longitudinal analyses, Pa infection within 6 months preceding enrollment was associated with a significantly greater rate of decline in z-scores for forced expiratory flow between 25 and 75% of forced vital capacity (FEF(25-75) ) (-1.3 vs. -0.4 Z scores/year, P = 0.024) and greater thoracoabdominal asynchrony measured by IP (mean phase angle difference 4.6°, P = 0.004). No other significant longitudinal associations were observed.
  
  
  CONCLUSIONS
  Prior Pa infection is associated with a greater rate of decline in FEF(25-75) z-score and mild thoracoabdominal asynchrony in preschool children with CF. In this multicenter US study, significant associations between other lung function measures and clinical features were not detected.
authors.affiliation: University of Rochester, Rochester, New York 14642, USA. clement_ren@urmc.rochester.edu
authors.forename: Clement L
authors.initials: CL
authors.lastname: Ren
authors.forename: Margaret
authors.initials: M
authors.lastname: Rosenfeld
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Mayer
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Davis
authors.forename: Margaret
authors.initials: M
authors.lastname: Kloster
authors.forename: Robert G
authors.initials: RG
authors.lastname: Castile
authors.forename: Peter W
authors.initials: PW
authors.lastname: Hiatt
authors.forename: Meeghan
authors.initials: M
authors.lastname: Hart
authors.forename: Robin
authors.initials: R
authors.lastname: Johnson
authors.forename: Paul
authors.initials: P
authors.lastname: Jones
authors.forename: Lyndia C
authors.initials: LC
authors.lastname: Brumback
authors.forename: Gwendolyn S
authors.initials: GS
authors.lastname: Kerby
mesh_terms: D002675:Child, Preschool; D015331:Cohort Studies; D003371:Cough / Q000150:complications*; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000150:complications* / Q000503:physiopathology*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D006801:Humans; D008137:Longitudinal Studies; D009991:Oscillometry; D010991:Plethysmography; D011552:Pseudomonas Infections / Q000150:complications*; D011550:Pseudomonas aeruginosa; D013147:Spirometry; D014028:Tobacco Smoke Pollution
chemical_list: C505032:CFTR protein, human; D014028:Tobacco Smoke Pollution; D019005:Cystic Fibrosis Transmembrane Conductance Regulator