title: Early life exposure to diagnostic radiation and ultrasound scans and risk of childhood cancer: case-control study.
abstract: OBJECTIVE
  To examine childhood cancer risks associated with exposure to diagnostic radiation and ultrasound scans in utero and in early infancy (age 0-100 days).
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  England and Wales.
  
  
  METHODS
  2690 childhood cancer cases and 4858 age, sex, and region matched controls from the United Kingdom Childhood Cancer Study (UKCCS), born 1976-96.
  
  
  METHODS
  Risk of all childhood cancer, leukaemia, lymphoma, and central nervous system tumours, measured by odds ratios.
  
  
  RESULTS
  Logistic regression models conditioned on matching factors, with adjustment for maternal age and child's birth weight, showed no evidence of increased risk of childhood cancer with in utero exposure to ultrasound scans. Some indication existed of a slight increase in risk after in utero exposure to x rays for all cancers (odds ratio 1.l4, 95% confidence interval 0.90 to 1.45) and leukaemia (1.36, 0.91 to 2.02), but this was not statistically significant. Exposure to diagnostic x rays in early infancy (0-100 days) was associated with small, non-significant excess risks for all cancers and leukaemia, as well as increased risk of lymphoma (odds ratio 5.14, 1.27 to 20.78) on the basis of small numbers.
  
  
  CONCLUSIONS
  Although the results for lymphoma need to be replicated, all of the findings indicate possible risks of cancer from radiation at doses lower than those associated with commonly used procedures such as computed tomography scans, suggesting the need for cautious use of diagnostic radiation imaging procedures to the abdomen/pelvis of the mother during pregnancy and in children at very young ages.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD 20892-7238, USA. rajarama@mail.nih.gov
authors.forename: Preetha
authors.initials: P
authors.lastname: Rajaraman
authors.forename: Jill
authors.initials: J
authors.lastname: Simpson
authors.forename: Gila
authors.initials: G
authors.lastname: Neta
authors.forename: Amy
authors.initials: A
authors.lastname: Berrington de Gonzalez
authors.forename: Pat
authors.initials: P
authors.lastname: Ansell
authors.forename: Martha S
authors.initials: MS
authors.lastname: Linet
authors.forename: Elaine
authors.initials: E
authors.lastname: Ron
authors.forename: Eve
authors.initials: E
authors.lastname: Roman
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology; D016017:Odds Ratio; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000009:adverse effects*; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology; D011859:Radiography / Q000009:adverse effects*; D012307:Risk Factors; D014463:Ultrasonography / Q000009:adverse effects*; D014852:Wales / Q000453:epidemiology