title: Intussusception in early childhood: a cohort study of 1.7 million children.
abstract: OBJECTIVE
  To describe incidence and temporal trends of intussusceptions in Danish children during 1980 to 2001.
  
  
  METHODS
  A population-based cohort study was conducted of 1.67 million children who were younger than 5 years during 1980 to 2001 and were followed up for 6.66 million person-years. The Danish National Patient Registry was used to identify cases of intussusception in the cohort. Age-specific incidence rates were main outcome measure.
  
  
  RESULTS
  A total of 1814 cases of intussusception among children who were younger than 5 years were reported from 1980 to 2001. The incidence rate remained fairly constant during 1980 to 1990 but decreased by 55% (95% confidence interval: 43%-65%) from 1990 to 2001. The reduction was most pronounced among children aged 3 to 5 months.
  
  
  CONCLUSIONS
  The incidence of intussusception among Danish children declined significantly during the 1990s, particularly among infants 3 to 5 months of age.
authors.affiliation: Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, MS-A34, Atlanta, GA 30333, USA. thf7@cdc.gov
authors.forename: Thea Kølsen
authors.initials: TK
authors.lastname: Fischer
authors.forename: Kristine
authors.initials: K
authors.lastname: Bihrmann
authors.forename: Michael
authors.initials: M
authors.lastname: Perch
authors.forename: Anders
authors.initials: A
authors.lastname: Koch
authors.forename: Jan
authors.initials: J
authors.lastname: Wohlfahrt
authors.forename: Mølbak
authors.initials: M
authors.lastname: Kåre
authors.forename: Mads
authors.initials: M
authors.lastname: Melbye
mesh_terms: D017677:Age Distribution; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data / Q000639:trends; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007443:Intussusception / Q000453:epidemiology*; D008297:Male; D016012:Poisson Distribution; D012044:Regression Analysis; D017678:Sex Distribution