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

• Main Authors: Scotet Virginie, Duguépéroux Ingrid, Saliou Philippe, Rault Gilles, Roussey Michel, Audrézet Marie-Pierre, Férec Claude
• Format: Article
• Language: English
• Published: BMC 2012-03-01
• Series: Orphanet Journal of Rare Diseases
• Subjects: Cystic fibrosis; Incidence; Time trends; Newborn screening; Pregnancy ultrasound examination
• Online Access: http://www.ojrd.com/content/7/1/14

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>This study enrolled CF patients born in Brittany between January 1^st1975 and December 31^st2009 (n = 483). Time trends in incidence were examined using Poisson regression and mainly expressed using the average percent change (APC).</p> <p>Results</p> <p>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).</p> <p>Conclusions</p> <p>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.</p>