Maternal and childhood medical history and the risk of childhood brain tumours: a case-control study in Ontario, Canada

Abstract

Background: Studies to date have yielded inconclusive results as to whether maternal medical history during pregnancy, and a child's early-life medical history contribute to the development of childhood brain tumours (CBTs). This study examined associations between maternal and childhood medical history and the risk of CBTs.

Methods: The Childhood Brain Tumour Epidemiology Study of Ontario (CBREO) examined children 0-15 years of age with newly diagnosed CBTs from 1997 to 2003. Multivariable logistic regression analysis determined associations for prenatal medications and childhood medical history, adjusted for child's demographics, and maternal education. Analyses were stratified by histology. A latency period analysis was conducted using 12- and 24-month lead times.

Results: Maternal intake of immunosuppressants during the prenatal period was significantly associated with glial tumours (OR 2.73, 95% CI 1.17-6.39). Childhood intake of anti-epileptics was significantly associated with CBTs overall, after accounting for 12-month (OR 8.51, 95% CI 3.35-21.63) and 24-month (OR 6.04, 95% CI 2.06-17.70) lead time before diagnosis. No associations for other medications were found.

Conclusions: This study underscores the need to examine potential carcinogenic effects of the medication classes highlighted and of the indication of medication use. Despite possible reverse causality, increased CBT surveillance for children with epilepsy might be warranted.

Fig. 1. Odds ratios and 95% confidence intervals for the associations between maternal medication use during pregnancy and histology* of childhood brain tumours.

*Histological subtype glial tumor for maternal exposure to immunosuppressants. OR odds ratio, CI confidence interval. Adjusted for child age at the reference date, child sex, child ethnicity, maternal education, and geographical region.

Fig. 2. Childhood anti-epilepsy medications and childhood brain tumour.

OR odds ratio, CI confidence interval. Adjusted ORs for use of childhood anti-epilepsy medications (yes vs. no) and duration of anti-epilepsy medication use in units of 3 months increment, excluding cases and controls whose anti-epilepsy medication use initiated within 12 months or 24 months of their reference date. Adjusted for child age at reference date, child sex, child ethnicity, maternal education, maternal alcohol consumption during pregnancy (never vs. ever), geographical region, and childhood head injury prior to reference date (yes vs. no).