Supplementary oxygen and risk of childhood lymphatic leukaemia.
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.
Naumburg
E
E
Department of Women 's and Children's Health, Section for Pediatrics, Uppsala University, Uppsala, Sweden. estelle.naumburg@kbh.uu.se
Bellocco
R
R
Cnattingius
S
S
Jonzon
A
A
Ekbom
A
A
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