Background: High birthweight is a potential risk factor for childhood brain tumours, particularly astrocytomas. We investigated several birth characteristics in relationship to brain cancers in young children.
Methods: We obtained 849 invasive central nervous system (CNS) cancer cases, ages 0-4 years, from California's population-based cancer registry for 1988-1997. We matched 746 (88%) of these cases to a California live birth certificate. We randomly selected two control birth certificates for each case, matched on date of birth and gender. We used conditional logistic regression to obtain odds ratios (OR) and 95% CI. The birth characteristics examined included birthweight, gestational age, race, parental age, and parental education.
Results: Analysing all CNS tumours combined, we found that children of other racial/ ethnic groups had OR below one compared with non-Hispanic white children. When adjusted for gestational age, race/ethnicity, and mother's place of birth, the OR for high birthweight (>/=4000 g) was 1.05 (95% CI: 0.79-1.38) compared with children with birthweights of 2500-3999 g. For astrocytomas (313 cases), the adjusted OR for high birthweight was 1.40 (95% CI: 0.90-2.18). When parental education was included in the model (available for only a subset of the birth years), the adjusted OR was 1.71 (95% CI: 1.01-2.90). High birthweight did not appear to be a risk factor for primitive neuroectodermal tumours (PNET).
Conclusions: We found high birthweight associated with increased risk of astrocytomas, but not PNET, in young children.