title: Risk factors for intussusception in infants in Vietnam and Australia: adenovirus implicated, but not rotavirus.
abstract: OBJECTIVE
  This study aimed to investigate risk factors for the development of intussusception in infants in a developing country with a suspected high incidence and in a developed country with a low incidence.
  
  
  METHODS
  A prospective case-control study of infants <2 years of age with idiopathic intussusception confirmed by air enema or surgery was conducted at the National Hospital of Paediatrics (NHP), Vietnam (n = 533) and the Royal Children's Hospital (RCH), Australia (n = 51). Diagnosis was validated in a subset (84% NHP; 67% RCH) by an independent blinded radiologist. Risk factor assessment was performed using a standardized questionnaire. Stool specimens were assayed for bacterial, viral, and parasitic agents.
  
  
  RESULTS
  The incidence of intussusception in Vietnam was 302/100,000 in infants <1 year of age (95% CI: 258-352), substantially higher than in Australia (71/100,000). A strong association with adenovirus infection was observed at both sites (cases positive at NHP: 34%, OR 8.2; cases positive at RCH: 40%, OR 44). No association was identified between intussusception and rotavirus, other enteric pathogens, oral polio vaccine, feeding practices, or living conditions.
  
  
  CONCLUSIONS
  The incidence of intussusception in infants was markedly higher in Vietnam than in Australia. A strong association between adenovirus infection and intussusception was identified at both sites suggesting that adenovirus may play a role in the etiology of intussusception.
authors.affiliation: Department of Gastroenterology and Clinical Nutrition, Emergency Medicine, Microbiology, Clinical Epidemiology and Biostatistics Unit, Royal Children's Hospital, Parkville, Australia. julie.bines@rch.org.au
authors.forename: Julie E
authors.initials: JE
authors.lastname: Bines
authors.forename: Nguyen Thanh
authors.initials: NT
authors.lastname: Liem
authors.forename: Frances A
authors.initials: FA
authors.lastname: Justice
authors.forename: Tran Ngoc
authors.initials: TN
authors.lastname: Son
authors.forename: Carl D
authors.initials: CD
authors.lastname: Kirkwood
authors.forename: Margaret
authors.initials: M
authors.lastname: de Campo
authors.forename: Peter
authors.initials: P
authors.lastname: Barnett
authors.forename: Ruth F
authors.initials: RF
authors.lastname: Bishop
authors.forename: Roy
authors.initials: R
authors.lastname: Robins-Browne
authors.forename: John B
authors.initials: JB
authors.lastname: Carlin
mesh_terms: D000258:Adenovirus Infections, Human / Q000150:complications*; D001315:Australia; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007223:Infant; D007443:Intussusception / Q000821:virology*; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012400:Rotavirus Infections; D014744:Vietnam