Parental smoking and risk of childhood brain tumors

Abstract

Childhood brain tumors (CBT) are the leading cause of cancer death in children, yet their etiology remains largely unknown. Tobacco smoke contains 61 known carcinogens and increases the risk of several adult cancers. This study investigated associations between parental smoking and risk of CBT in a population-based case-control study conducted between 2005 and 2010. Cases were identified through all ten Australian pediatric oncology centers, controls via nationwide random-digit dialing, frequency matched to cases on age, sex and state of residence. Parental smoking information was obtained for 302 cases and 941 controls through mailed questionnaires that requested average daily cigarette use in each calendar year from age 15 to the child's birth, linked to residential and occupational histories. Data were analyzed using unconditional logistic regression, adjusting for frequency matching variables and potential confounders. Overall, parental smoking before or during pregnancy showed no association with CBT risk. The odds ratios for maternal smoking before and during pregnancy were 0.99 (95% CI: 0.70, 1.40) and 0.89 (95% CI: 0.61, 1.21), respectively, and those for paternal smoking before and during pregnancy were 0.99 (95% CI: 0.71, 1.38) and 1.04 (95% CI: 0.74, 1.46), respectively. In children under 24 months of age, the odds ratios for maternal smoking preconception and during pregnancy were 5.06 (95% CI 1.35-19.00) and 4.61 (95% CI: 1.08, 19.63), although these results were based on modest numbers. Future studies should investigate the associations between maternal smoking and risk of CBT by the child's age of diagnosis. What's new? Brain malignancies are a major cause of cancer-related death in children and in many cases are of unknown etiology. Investigation of a possible etiological role for tobacco smoke in childhood brain tumors in Australia reveals here that while overall parental smoking is unrelated to tumor risk, maternal smoking during pregnancy may be associated with a four-fold increase in risk among children under age two. The findings warrant further investigation into associations between maternal smoking and brain tumor risk by child's age of diagnosis. Copyright © 2012 UICC.