Evidence for decline in the incidence of cystic fibrosis: a 35-year observational study in Brittany, France

Orphanet J Rare Dis. 2012 Mar 1;7:14. doi: 10.1186/1750-1172-7-14.

Abstract

Background: Cystic fibrosis (CF) is an autosomal recessive disorder whose incidence has long been estimated as 1/2500 live births in Caucasians. Expanding implementation of newborn screening (NBS) programs now allows a better monitoring of the disease incidence, what is essential to make reliable predictions for disease management. This study assessed time trends in the birth incidence of CF over a long period (35 years: 1975-2009) in an area where CF is frequent (Brittany, France) and where NBS has been implemented for more than 20 years.

Methods: This study enrolled CF patients born in Brittany between January 1st 1975 and December 31st 2009 (n = 483). Time trends in incidence were examined using Poisson regression and mainly expressed using the average percent change (APC).

Results: The average number of patients born each year declined from 18.6 in the late 1970's (period 1975-79) to 11.6 nowadays (period 2005-09). The corresponding incidence rates dropped from 1/1983 to 1/3268, which represented a decline close to 40% between these two periods (APC = -39.3%, 95% CI = -55.8% to -16.7%, p = 0.0020). A clear breakpoint in incidence rate was observed at the end of the 1980's (p < 0.0001). However, the incidence rate has remained quite stable since that time (annual APC = -1.0%, 95% CI = -3.0% to 1.1%, p = 0.3516).

Conclusions: This study provides an accurate picture of the evolution of the incidence of a genetic disease over a long period and highlights how it is influenced by the health policies implemented. We observed a 40% drop in incidence in our area which seems consecutive to the availability of prenatal diagnosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cystic Fibrosis / diagnosis
  • Cystic Fibrosis / diagnostic imaging
  • Cystic Fibrosis / epidemiology*
  • Female
  • France / epidemiology
  • Humans
  • Incidence
  • Infant, Newborn
  • Male
  • Neonatal Screening / methods
  • Pregnancy
  • Prenatal Diagnosis / methods
  • Time Factors
  • Ultrasonography, Prenatal