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Positive associations have been reported between the measures of accelerated fetal growth and risk of childhood acute lymphoblastic leukemia (ALL). We investigated this association by pooling individual-level data from 12 case-control studies participating in the Childhood Leukemia International Consortium. Two measures of fetal growth-weight-for-gestational-age and proportion of optimal birth weight (POBW)-were analysed. Study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression, and combined in fixed effects meta-analyses. Pooled analyses of all data were also undertaken using multivariable logistic regression. Subgroup analyses were undertaken when possible. Data on weight for gestational age were available for 7,348 cases and 12,489 controls from all 12 studies and POBW data were available for 1,680 cases and 3,139 controls from three studies. The summary ORs from the meta-analyses were 1.24 (95% CI: 1.13, 1.36) for children who were large for gestational age relative to appropriate for gestational age, and 1.16 (95% CI: 1.09, 1.24) for a one-standard deviation increase in POBW. The pooled analyses produced similar results. The summary and pooled ORs for small-for-gestational-age children were 0.83 (95% CI: 0.75, 0.92) and 0.86 (95% CI: 0.77, 0.95), respectively. Results were consistent across subgroups defined by sex, ethnicity and immunophenotype, and when the analysis was restricted to children who did not have high birth weight. The evidence that accelerated fetal growth is associated with a modest increased risk of childhood ALL is strong and consistent with known biological mechanisms involving insulin-like growth factors. © 2013 UICC., (Copyright © 2013 UICC.)

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., (Copyright © 2012 UICC.)