title: Head injury, diagnostic X-rays, and risk of medulloblastoma and primitive neuroectodermal tumor: a Children's Oncology Group study.
abstract: OBJECTIVE
  A comprehensive case-control study was conducted to determine potential risk factors for medulloblastoma/primitive neuroectodermal tumor (PNET), a common brain tumor in children. This analysis evaluated possible associations between previous head injury and ionizing radiation exposure through diagnostic X-rays and medulloblastoma/PNET.
  
  
  METHODS
  Mothers of 318 cases <6 years of age at diagnosis between 1991 and 1997 and registered with the Children's Oncology Group were interviewed. Mothers of 318 matching controls were selected through random digit dialing and interviewed.
  
  
  RESULTS
  An association was not detected between previous head injury (OR: 0.78, 95% CI: 0.40-1.5) or head X-ray for any reason including head injury with medulloblastoma/PNET. A statistically non-significant excess of cases reported having an X-ray for reason other than head injury (OR 2.3, 95% CI 0.91-5.7). When cases that received an X-ray for a common symptom of medulloblastoma/PNET were considered unexposed this association weakened (OR: 1.3, 95% CI: 0.49-3.7). No dose-response relationship was observed.
  
  
  CONCLUSIONS
  Head injury and exposure to diagnostic head X-rays were not associated with medulloblastoma/PNET in this study. Future studies should investigate all imaging procedures with ionizing radiation exposure including computed tomography scans and utilize radiation dose estimations.
authors.affiliation: Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, PA, USA.
authors.forename: Saira
authors.initials: S
authors.lastname: Khan
authors.forename: Alison A
authors.initials: AA
authors.lastname: Evans
authors.forename: Lucy
authors.initials: L
authors.lastname: Rorke-Adams
authors.forename: Manuela A
authors.initials: MA
authors.lastname: Orjuela
authors.forename: Tania
authors.initials: T
authors.lastname: Shiminski-Maher
authors.forename: Greta R
authors.initials: GR
authors.lastname: Bunin
mesh_terms: D001932:Brain Neoplasms / Q000209:etiology*; D016022:Case-Control Studies; D002528:Cerebellar Neoplasms / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D006259:Craniocerebral Trauma / Q000150:complications*; D006801:Humans; D007223:Infant; D008527:Medulloblastoma / Q000209:etiology*; D018242:Neuroectodermal Tumors, Primitive / Q000209:etiology*; D011859:Radiography / Q000009:adverse effects; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data; D012307:Risk Factors; D011795:Surveys and Questionnaires