title: Exposure to diagnostic radiological procedures and the risk of childhood acute lymphoblastic leukemia.
abstract: BACKGROUND
  Diagnostic irradiation of the mother during pregnancy increases the risk of childhood acute lymphoblastic leukemia (ALL). There is inconsistent evidence on associations between ALL and other parental or childhood diagnostic irradiation. The aim of this analysis is to investigate whether diagnostic X-rays of the mother before birth, of the father before conception, or of the child increased the risk of childhood ALL.
  
  
  METHODS
  Data from 389 cases and 876 frequency-matched controls were analyzed using unconditional logistic regression, adjusting for study matching factors and potential confounders. A meta-analysis of our findings in relation to paternal X-rays before conception with the published findings of previous studies was also conducted.
  
  
  RESULTS
  There was no evidence of an increased risk with maternal abdominal X-rays before the birth of the index child or with the child having any X-rays more than 6 months before the censoring date. The odds ratio (OR) for any paternal abdominal X-ray before conception was 1.17 [95% confidence interval (95% CI), 0.88-1.55], and 1.47 (95% CI, 0.98-2.21) for more than one X-ray. The OR for any paternal intravenous pyelogram before conception was 3.56 (95% CI, 1.59-7.98). The pooled OR for this study with previous studies of any paternal abdominal X-rays before conception was 1.17 (95% CI, 0.92-1.48).
  
  
  CONCLUSIONS
  There was some evidence of an increased risk of ALL in the offspring if the father had more than one abdominal X-ray before conception or had ever had an intravenous pyelogram.
  
  
  CONCLUSIONS
  We plan to repeat this analysis by using pooled data to improve precision.
authors.affiliation: Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia. helenb@ichr.uwa.edu.au
authors.forename: Helen D
authors.initials: HD
authors.lastname: Bailey
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Armstrong
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: de Klerk
authors.forename: Lin
authors.initials: L
authors.lastname: Fritschi
authors.forename: John
authors.initials: J
authors.lastname: Attia
authors.forename: Liane
authors.initials: L
authors.lastname: Lockwood
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Milne
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005220:Fathers; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D009035:Mothers; D016017:Odds Ratio; D018812:Paternal Exposure / Q000009:adverse effects*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy / Q000528:radiation effects*; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000209:etiology*; D011859:Radiography / Q000009:adverse effects*; D012307:Risk Factors; D014965:X-Rays / Q000009:adverse effects