title: Supplementary oxygen and risk of childhood lymphatic leukaemia.
abstract: OBJECTIVE
  Childhood leukaemia has been linked to several factors, such as asphyxia and birthweight, which in turn are related to newborn resuscitation. Based on the findings from a previous study a population-based case-control study was performed to investigate the association between childhood leukaemia and exposure to supplementary oxygen and other birth-related factors.
  
  
  METHODS
  Children born in Sweden and diagnosed with lymphatic leukaemia between 1973 and 1989 (578 cases) were individually matched by gender and date of birth to a randomly selected control. Children with Down's syndrome were excluded. Exposure data were blindly gathered from antenatal, obstetric and other standardized medical records. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated by conditional logistic regression.
  
  
  RESULTS
  Resuscitation with 100% oxygen with a facemask and bag immediately postpartum was significantly associated with an increased risk of childhood lymphatic leukaemia (OR = 2.57, 95% Cl 1.21-6.82). The oxygen-related risk further increased if the manual ventilation lasted for 3 min or more (OR = 3.54, 95% CI 1.16-10.80). Low Apgar scores at 1 and 5 min were associated with a non-significantly increased risk of lymphatic leukaemia. There were no associations between lymphatic leukaemia and supplementary oxygen later in the neonatal period or other birth-related factors.
  
  
  CONCLUSIONS
  Resuscitation with 100% oxygen immediately postpartum is associated with childhood lymphatic leukaemia, but further studies are warranted to confirm the findings.
authors.affiliation: Department of Women 's and Children's Health, Section for Pediatrics, Uppsala University, Uppsala, Sweden. estelle.naumburg@kbh.uu.se
authors.forename: E
authors.initials: E
authors.lastname: Naumburg
authors.forename: R
authors.initials: R
authors.lastname: Bellocco
authors.forename: S
authors.initials: S
authors.lastname: Cnattingius
authors.forename: A
authors.initials: A
authors.lastname: Jonzon
authors.forename: A
authors.initials: A
authors.lastname: Ekbom
mesh_terms: D000293:Adolescent; D001034:Apgar Score; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007223:Infant; D007945:Leukemia, Lymphoid / Q000453:epidemiology* / Q000209:etiology; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects*; D012151:Resuscitation / Q000009:adverse effects; D013548:Sweden / Q000453:epidemiology