title: Fathers' occupational contacts and risk of childhood leukemia and non-hodgkin lymphoma.
abstract: BACKGROUND
  There is evidence to suggest that childhood leukemia and non-Hodgkin lymphoma have an infective etiology. We investigated the risk of childhood leukemia and non-Hodgkin lymphoma in relation to paternal occupational contact with other individuals, a surrogate for potential exposure to infection.
  
  
  METHODS
  We carried out a case-control study using 792 cases from the Northern Region Young Persons' Malignant Disease Registry, United Kingdom, 1968-1997, and 2 large population-based control groups. Paternal occupations at birth were classified as having standard, high, or very high levels of contact. Conditional logistic regression was used in the analysis.
  
  
  RESULTS
  There was an increased risk of childhood leukemia and non-Hodgkin lymphoma in those children whose fathers' occupational contacts were high or very high compared with standard (odds ratio = 1.3; 95% confidence interval = 1.0-1.5). The excess risk in the very high group was most pronounced for 245 cases of acute lymphoblastic leukemia aged 2 to 5 years at diagnosis (1.5; 1.1-2.1). The risk with paternal occupational contacts was greater in rural areas, although it was also present in urban areas. The risks of leukemia and non-Hodgkin lymphoma were also higher among the offspring of men employed as policemen, sales representatives, or teachers.
  
  
  CONCLUSIONS
  Our findings are consistent with the hypothesis of an infective etiology for childhood leukemia and non-Hodgkin lymphoma, and they add to the evidence that infections could be transmitted to children by adults.
authors.affiliation: Paediatric and Lifecourse Epidemiology Research Group, School of Clinical Medical Sciences, University of Newcastle upon Tyne, UK. m.s.spearce@ncl.ac.uk
authors.forename: Mark S
authors.initials: MS
authors.lastname: Pearce
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Cotterill
authors.forename: Louise
authors.initials: L
authors.lastname: Parker
mesh_terms: D000328:Adult; D017677:Age Distribution; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D018812:Paternal Exposure; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology* / Q000209:etiology*; D011379:Prognosis; D012016:Reference Values; D012042:Registries; D018570:Risk Assessment; D017678:Sex Distribution; D016019:Survival Analysis; D006113:United Kingdom / Q000453:epidemiology