title: National time trends in congenital heart defects, Denmark, 1977-2005.
abstract: BACKGROUND
  Time trends in congenital heart defects (CHD) by specific phenotype and with long follow-up time are rarely available for an entire population. We present trends in national CHD prevalences over the past 3 decades.
  
  
  METHODS
  We linked information from the National Patient Register, the Causes of Death Register, and the Danish Cytogenetic Central Register for all persons born in Denmark, 1977 to 2005, and registered in the Civil Registration System, yielding a cohort of 1,763,591 persons-18,207 with CHD. Individuals with CHDs were classified by phenotype (heterotaxia, conotruncal defect, atrioventricular septal defect, anomalous pulmonary venous return, left and right ventricular outflow tract obstructions, septal defects, complex defects, associations, patent ductus arteriosus, unspecified, and other specified) by combining International Classification of Diseases codes using a hierarchical approach.
  
  
  RESULTS
  From 1977 to 2005, the overall CHD birth prevalence increased from 73 to 113 per 10,000 live births. Generally, prevalence increased for defects diagnosed in infancy, until 1996-1997, and then stabilized. For each 5-year interval, isolated septal defects and severe defects increased by 22% (95% CI, 20%-25%) and 5% (95% CI, 4%-7%), respectively. Among the severe defects, conotruncal defects and atrioventricular septal defect showed the largest prevalence increases. Women had a lower prevalence of severe defects during the 1980s. The CHD prevalence increase was unchanged when persons with extracardiac defects or chromosomal aberrations were excluded.
  
  
  CONCLUSIONS
  CHD birth prevalence increased from the beginning of the 1980s but stabilized in the late 1990s.
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark. noy@ssi.dk
authors.forename: Nina
authors.initials: N
authors.lastname: Oyen
authors.forename: Gry
authors.initials: G
authors.lastname: Poulsen
authors.forename: Heather A
authors.initials: HA
authors.lastname: Boyd
authors.forename: Jan
authors.initials: J
authors.lastname: Wohlfahrt
authors.forename: Peter K A
authors.initials: PK
authors.lastname: Jensen
authors.forename: Mads
authors.initials: M
authors.lastname: Melbye
mesh_terms: D003718:Denmark / Q000453:epidemiology; D004374:Ductus Arteriosus, Patent / Q000453:epidemiology; D005260:Female; D006330:Heart Defects, Congenital / Q000145:classification / Q000453:epidemiology*; D006343:Heart Septal Defects / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D011667:Pulmonary Veins / Q000002:abnormalities; D012042:Registries; D014694:Ventricular Outflow Obstruction / Q000453:epidemiology