title: Immunophenotype and cytogenetic characteristics in the relationship between birth weight and childhood leukemia.
abstract: BACKGROUND
  High birth weight increases the risk of childhood acute lymphoid leukemia (ALL) through unknown mechanisms. Whether this risk is specific to ALL subtypes is unknown, and low case numbers have prevented investigation of the rarer leukemias. Here we address these associations using a large population-based dataset.
  
  
  METHODS
  Using the National Registry of Childhood Tumors, birth weights of 7,826 leukemia cases, defined by immunophenotype and cytogenetic subgroup, were compared with those of 10,785 controls born in England and Wales between 1980 and 2007.
  
  
  RESULTS
  The risk for overall leukemia increases 7% with each 0.5 kg increase in birth weight (OR 1.07, 95%CI 1.04-1.10). This risk is limited to the lymphoid leukemias (OR 1.08, 95%CI 1.05-1.12) diagnosed between 1 and 9 years of age. Analysis by cytogenetic feature reveals that there appears to be association with specific chromosomal abnormality: the risk of tumors with high hyperdiploid karyotypes increases 12% per 0.5 kg increase in birth weight (OR 1.12, 95%CI 1.05-1.20), and t(1;19) tumors show an increased risk of 41% per 0.5 kg increase (OR 1.41, 95%CI 1.09-1.84). The risk of acute myeloid leukemia is elevated in high and low birth weight babies. There is no significant risk relationship to other leukemias or myeloproliferative diseases.
  
  
  CONCLUSIONS
  Birth weight is a risk factor for ALL and AML. Other subtypes of the disease are not significantly affected. There appears to be association with specific chromosomal abnormality, which may aid our understanding of the development of childhood leukemia in utero.
authors.affiliation: Childhood Cancer Research Group, University of Oxford, Oxford, UK. kate.oneill@ccrg.ox.ac.uk
authors.forename: Kate A
authors.initials: KA
authors.lastname: O'Neill
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Bunch
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Vincent
authors.forename: Logan G
authors.initials: LG
authors.lastname: Spector
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Moorman
authors.forename: Michael F G
authors.initials: MF
authors.lastname: Murphy
mesh_terms: D000293:Adolescent; D001724:Birth Weight; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D020732:Cytogenetic Analysis; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism; D008297:Male; D009190:Myelodysplastic Syndromes / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism; D009196:Myeloproliferative Disorders / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome