title: Evolution of pancreatic function during the first year in infants with cystic fibrosis.
abstract: OBJECTIVE
  To describe pancreatic function during the first year of life in infants diagnosed with cystic fibrosis (CF) using serial fecal elastase measurements.
  
  
  METHODS
  This was a longitudinal study of 82 infants diagnosed with CF through newborn screening. Monthly stool samples were sent to a central laboratory for fecal elastase measurements.
  
  
  RESULTS
  A total of 61 infants had an initial stool sample obtained at age <3.5 months and a final stool sample obtained at age >9 months. Twenty-six of 29 infants with a fecal elastase value <50 μg/g at study entry had a fecal elastase value <200 μg/g (the accepted cutoff value for pancreatic insufficiency) on all measurements during the year; all 29 had a value <200 μg/g at the end of the study. Of the 48 infants with initial fecal elastase value <200 μg/g, 13 had at least 1 fecal elastase value >200 μg/g but had a final stool fecal elastase value <200 μg/g; however, 4 infants with an initial fecal elastase value <200 μg/g ended the year with a value >200 μg/g. Eleven of 13 infants with an initial fecal elastase value of >200 μg/g still had a value >200 μg/g at the end of the first year.
  
  
  CONCLUSIONS
  Infants with CF exhibit variability in fecal elastase values during the first year. Infants with a fecal elastase level of 50-200 μg/g at diagnosis should be treated with pancreatic enzyme replacement therapy, but fecal elastase should be remeasured at age 1 year to ensure that those with a falsely low value do not continue to receive pancreatic enzyme replacement therapy unnecessarily. Those with a fecal elastase value >200 μg/g initially can become pancreatic insufficient with time.
authors.affiliation: Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA. Brian.O'Sullivan@umassmemorial.org
authors.forename: Brian P
authors.initials: BP
authors.lastname: O'Sullivan
authors.forename: Dawn
authors.initials: D
authors.lastname: Baker
authors.forename: Katherine G
authors.initials: KG
authors.lastname: Leung
authors.forename: George
authors.initials: G
authors.lastname: Reed
authors.forename: Susan S
authors.initials: SS
authors.lastname: Baker
authors.forename: Drucy
authors.initials: D
authors.lastname: Borowitz
mesh_terms: D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000150:complications / Q000235:genetics / Q000503:physiopathology*; D004281:Docosahexaenoic Acids / Q000378:metabolism; D010188:Exocrine Pancreatic Insufficiency / Q000175:diagnosis / Q000235:genetics; D005243:Feces; D005260:Female; D005838:Genotype; D006720:Homozygote; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D015997:Neonatal Screening; D010196:Pancreatic Elastase / Q000378:metabolism; D010186:Pancreatic Function Tests / Q000379:methods*
chemical_list: D004281:Docosahexaenoic Acids; D010196:Pancreatic Elastase