title: Cystic fibrosis birth rates in Canada: a decreasing trend since the onset of genetic testing.
abstract: OBJECTIVE
  To estimate cystic fibrosis (CF) birth rates in Canada from 1971 to 2000 and to assess the population impact of genetic testing in families with a history of CF, after identification of the CF transmembrane conductance regulator gene in 1989.
  
  
  METHODS
  Age-at-diagnosis data were obtained from the Canadian Cystic Fibrosis Foundation Patient Data Registry and Canadian births for the corresponding years from Canadian Vital Statistics. Estimates of the CF birth rate in each year were based on a nonparametric model that allows the birth rate to vary across the years and adjusts for censoring of currently undiagnosed patients.
  
  
  RESULTS
  The overall CF birth rate from 1971-1987 was 1/2714 with no increasing or decreasing trend. Beginning in 1988, 1 year before identification of the CF transmembrane conductance regulator gene, estimated CF birth rates followed a linear decline to an estimated rate of 1/3608 in 2000. CF birth rates may have stabilized in the last few years, but further decline may occur with implementation of carrier screening in the general population.
  
  
  CONCLUSIONS
  These results demonstrate the temporal association of genetic testing and declining CF birth rates in Canada. They may assist in decisions relating to the allocation of resources for prenatal and neonatal CF screening programs.
authors.affiliation: The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Dupuis
authors.forename: David
authors.initials: D
authors.lastname: Hamilton
authors.forename: David E C
authors.initials: DE
authors.lastname: Cole
authors.forename: Mary
authors.initials: M
authors.lastname: Corey
mesh_terms: D001723:Birth Rate / Q000639:trends*; D002170:Canada / Q000453:epidemiology; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D005820:Genetic Testing; D006801:Humans; D016012:Poisson Distribution; D011296:Prenatal Diagnosis; D015995:Prevalence; D012042:Registries
chemical_list: C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator