title: The impact of early cystic fibrosis diagnosis on pulmonary function in children.
abstract: OBJECTIVE
  To investigate the impact of early diagnosis on pulmonary function in a large cohort of children with cystic fibrosis (CF).
  
  
  METHODS
  CF cases identified from the CF Foundation National Patient Registry and diagnosed between 1982 and 1990 were categorized as: early asymptomatic diagnosis (EAD; n = 157), early symptomatic diagnosis (ESD; n = 227), later asymptomatic diagnosis (LAD; n = 161), and later symptomatic diagnosis (LSD; n = 3080). Early CF diagnosis was diagnosis before 6 weeks of age; later diagnosis was diagnosis at 6 weeks to 36 months of age, inclusive. Asymptomatic diagnosis included diagnosis by either family history, genotype, prenatally, or neonatally. Pulmonary function was measured as percentage of predicted forced expiratory volume in one second (FEV(1)).
  
  
  RESULTS
  There were no overall differences in pulmonary function among the 4 diagnostic groups. However, EAD cases born more recently (1987 or later) had a higher mean FEV(1) throughout the study, compared with the remaining diagnostic groups. For this later birth cohort, Cox regression analysis for those diagnosed later and/or symptomatically, demonstrated a 2-fold increase in risk (P =.06) for having moderate-to-severe pulmonary function (FEV(1) <70%) at ages 6 to 10 years, compared with EAD cases.
  
  
  CONCLUSIONS
  Children diagnosed with CF early, asymptomatically and more recently may have better pulmonary function throughout early childhood, probably as a result of improved CF treatments in recent years.
authors.affiliation: Office of Genetics and Disease Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors.forename: Sophia S
authors.initials: SS
authors.lastname: Wang
authors.forename: Leslie A
authors.initials: LA
authors.lastname: O'Leary
authors.forename: Stacey C
authors.initials: SC
authors.lastname: Fitzsimmons
authors.forename: Muin J
authors.initials: MJ
authors.lastname: Khoury
mesh_terms: D016022:Case-Control Studies; D002648:Child; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008168:Lung / Q000503:physiopathology*; D008297:Male; D016016:Proportional Hazards Models; D012044:Regression Analysis; D013997:Time Factors