Risk Of Childhood Brain Tumors Research Articles

Maternal smoking, consumption of alcohol, and caffeinated beverages during pregnancy and the risk of childhood brain tumors: a meta-analysis of observational studies

BackgroundWe conducted this meta-analysis to investigate the potential association between maternal smoking, alcohol and caffeinated beverages consumption during pregnancy and the risk of childhood brain tumors (CBTs).MethodsA thorough search was carried out on PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Internet to identify pertinent articles. Fixed or random effects model was applied to meta-analyze the data.ResultsThe results suggested a borderline statistically significant increased risk of CBTs associated with maternal smoking during pregnancy (OR 1.04, 95% CI 0.99–1.09). We found that passive smoking (OR 1.12, 95% CI 1.03–1.20), rather than active smoking (OR 1.00, 95% CI 0.93–1.07), led to an increased risk of CBTs. The results suggested a higher risk in 0–1 year old children (OR 1.21, 95% CI 0.94–1.56), followed by 0–4 years old children (OR 1.12, 95% CI 0.97–1.28) and 5–9 years old children (OR 1.11, 95% CI 0.95–1.29). This meta-analysis found no significant association between maternal alcohol consumption during pregnancy and CBTs risk (OR 1.00, 95% CI 0.80–1.24). An increased risk of CBTs was found to be associated with maternal consumption of caffeinated beverages (OR 1.16, 95% CI 1.07–1.26) during pregnancy, especially coffee (OR 1.18, 95% CI 1.00–1.38).ConclusionsMaternal passive smoking, consumption of caffeinated beverages during pregnancy should be considered as risk factors for CBTs, especially glioma. More prospective cohort studies are warranted to provide a higher level of evidence.

Abstract PR-009: Associations between PM2.5, vegetation density and childhood brain tumors: a case-control registry-based study from Texas 1995-2011

Abstract Background: Air pollution has been reported to be associated with some childhood cancers, namely leukemias. Less is known about air pollution and childhood brain tumor risk. In adult cancers, increasing vegetation density, or greenness, has been inversely associated with cancer incidence and survival. The interplay between air pollution and greenness, which co-occur, in childhood cancer etiology is unclear. Therefore, we sought to estimate the association between prenatal and early life exposure to air pollution, greenness, and childhood cancer in Texas (1995-2011). Materials and Methods: We included 1,316 individuals with a childhood brain tumor diagnosed <17 years of age and 109,762 age- and sex-matched controls. We linked birth certificate residential address to census tract annual average particulate matter 2.5 µg/m³ (PM2.5) and Normalized Difference Vegetation Index (NDVI) to approximate prenatal and early life exposure to greenness and air pollution. We estimated odds ratios (OR) and 95% confidence intervals (95% CI) as the measure of association between PM2.5 and NDVI interquartile range (IQR) increases and brain tumors. Models were adjusted for birth year, sex, maternal race/ethnicity, and area-level socioeconomic status (Yost index). Results: The following brain tumor types were included: ependymoma (n=136), astrocytoma (n=619), medulloblastoma (n=187), PNET (n=57), ATRT (n=54), and other gliomas (n=263). Average birth year PM2.5 and NDVI exposure levels were similar in cases and controls, 11 µg/m³ and 0.4, respectively. Each IQR increase (2.6 µg/m³) in PM2.5 was associated with ependymoma (OR: 1.27, 95% CI: 1.01-1.60) when adjusting for control-derived quartiles of NDVI. Conversely, after adjusting for PM2.5 quartiles, each IQR increase in NDVI (0.13) was inversely associated with ependymoma in those diagnosed at 0-4 years of age (OR: 0.75, 95% CI: 0.56-0.97) and with medulloblastoma in those aged 0-16 years at diagnosis (OR: 0.75, 95% CI: 0.62-0.91). There was no evidence of statistical interaction between NDVI and PM2.5 (all Likelihood Ratio Test p-values>0.05) for any brain tumors. Conclusions: Increasing residential air pollution during prenatal and early life increased the risk of childhood ependymoma in Texas independent of greenness. Conversely, increasing greenness exposure in prenatal and early life decreased the risk of ependymoma and medulloblastoma independent of PM2.5. These findings highlight the complex relationship between air pollution and greenness in childhood cancer etiology. Citation Format: Lindsay Williams, David Haynes, Jeannette Sample, Laura McGuinn, Thanh Hoang, Philip Lupo, Michael Scheurer. Associations between PM2.5, vegetation density and childhood brain tumors: a case-control registry-based study from Texas 1995-2011 [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr PR-009.

Maternal and Perinatal Factors Associated With Childhood Brain Tumors: A Case-Control Study in Vietnam.

Brain cancer is the leading cause of cancer-related deaths in children and the majority of childhood brain tumors are diagnosed without determination of their underlying etiology. Little is known about risk factors for childhood brain tumors in Vietnam. The objective of this case-control study was to identify maternal and perinatal factors associated with brain tumors occurring in young Vietnamese children and adolescents. We conducted a hospital-based case-control study at Viet Duc University Hospital in Hanoi, Vietnam. Cases consisted of children with brain tumors aged 0-14years old admitted to the hospital from January 2020 to July 2022 while the controls were age and sex-matched hospitalized children diagnosed with head trauma. Perinatal characteristics were abstracted from hospital medical records and maternal medical, behavioral, and sociodemographic factors were collected through in-person interviews. Conditional logistic regression models were used to examine maternal and perinatal factors associated with childhood brain tumors. The study sample included 220 children (110 cases and 110 controls) whose average age was 8.9 years and 41.8% were girls. Children born to mothers aged greater than 30 years at the time of the child's birth had a higher risk of childhood brain tumors compared to those born to mothers aged from 18 to 30 years old (OR = 2.55; 95% CI: 1.13-5.75). Additionally low maternal body mass index prior to the current pregnancy of <18.5kg/m2 significantly increased the odds of having a child with a brain tumor in relation to normal maternal body mass index from 18.5-22.9kg/m2 (OR = 3.19; 95% CI: 1.36 - 7.50). Advanced maternal age and being markedly underweight were associated with an increased odds of having a child with a brain tumor. A population-based study with larger sample size is needed to confirm and extend the present findings.

Research of Pesticide Metabolites in Human Brain Tumor Tissues by Chemometrics-Based Gas Chromatography-Mass Spectrometry Analysis for a Hypothetical Correlation between Pesticide Exposure and Risk Factor of Central Nervous System Tumors.

Pesticides are widely used, resulting in continuing human exposure with potential health impacts. Some exposures related to agricultural works have been associated with neurological disorders. Since the 2000s, the hypothesis of the role of pesticides in the occurrence of central nervous system (CNS) tumors has been better documented in the literature. However, the etiology of childhood brain cancers still remains largely unknown. The major objective of this work was to assess the potential role of pesticide exposure as a risk factor for CNS tumors based on questionnaires and statistical analysis of information collected from patients hospitalized in the Neurosurgery Department of the Habib Bourguiba Hospital Medium in Sfax, Tunisia, during the period from January 1, 2022, to May 31, 2023. It also aimed to develop a simple and rapid analytical method by the gas chromatography-mass spectrometry technique for the research traces of pesticide metabolites in some collected human brain tumor tissues in order to more emphasize our hypothesis for such a correlation between pesticide exposure and brain tumor development. Patients with a history of high-risk exposure were selected to conduct further analysis. Chemometric methods were adapted to discern intrinsic variation between pathological and control groups and ascertain effective separation with the identification of differentially expressed metabolites accountable for such variations. Three samples revealed traces of pesticide metabolites that were mostly detected at an early age. The histopathological diagnosis was medulloblastoma for a 10-year-old child and high-grade gliomas for 27- and 35-year-old adults. The bivariate analyses (odds ratio >1 and P value <5%) confirmed the great probability of developing cancer by an exposure case. The Cox proportional hazards model revealed the risk of carcinogenicity beyond the age of 50 as a long-term effect of pesticide toxicity. Our study supports the correlation between pesticide exposure and the risk of development of human brain tumors, suggesting that preconception pesticide exposure, and possibly exposure during pregnancy, is associated with an increased childhood brain tumor risk. This hypothesis was enhanced in identifying traces of metabolites from the carbamate insecticide class known for their neurotoxicity and others from pyridazinone, organochlorines (OCs), triazole fungicide, and N-nitroso compounds known for their carcinogenicity. The 2D-OXYBLOT analysis confirmed the neurotoxicity effect of insecticides to induce oxidative damage in CNS cells. Aldicarb was implicated in brain carcinogenicity confirmed by the identification of oxime metabolites in a stress degradation study. Revealing "aziridine" metabolites from the OC class may better emphasize the theory of detecting traces of pesticide metabolites at an early age. Overall, our findings lead to the recommendation of limiting the residential use of pesticides and the support of public health policies serving this objective that we need to be vigilant in the postmarketing surveillance of human health impacts.

Breastfeeding and risk of childhood brain tumors: a report from the Childhood Cancer and Leukemia International Consortium.

Studies report mixed findings regarding the association of breastfeeding with childhood brain tumors (CBT), the leading causes of cancer-related mortality in young people. Our objective was to determine whether breastfeeding is associated with CBT incidence. We pooled data on N = 2610 cases with CBT (including 697 cases with astrocytoma, 447 cases with medulloblastoma/primitive neuroectodermal tumor [PNET], 167 cases with ependymoma) and N = 8128 age- and sex-matched controls in the Childhood Cancer and Leukemia International Consortium. We computed unconditional logistic regression models to estimate the odds ratio (OR) and 95% confidence interval (CI) of CBT, astrocytoma, medulloblastoma/PNET, and ependymoma according to breastfeeding status, adjusting for study, sex, mode of delivery, birthweight, age at diagnosis/interview, maternal age at delivery, maternal educational attainment, and maternal race/ethnicity. We evaluated any breastfeeding versus none and breastfeeding ≥ 6months versus none. We subsequently performed random effects meta-analysis to confirm our findings, identify potential sources of heterogeneity, and evaluate for outliers or influential studies. Breastfeeding was reported by 64.8% of control mothers and 64.5% of case mothers and was not associated with CBT (OR 1.04, 95% CI 0.94-1.15), astrocytoma (OR 1.01, 95% CI 0.87-1.17), medulloblastoma/PNET (OR 1.11, 95% CI 0.93-1.32), or ependymoma (OR 1.06, 95% CI 0.81-1.40). Results were similar when we restricted to breastfeeding ≥ 6months and in meta-analyses. Our data suggest that breastfeeding does not protect against CBT.

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

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. 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. 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. 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.

The risk of childhood brain tumors associated with delivery interventions: A Danish matched case-control study

BackgroundHead trauma has been associated with increased brain tumor risk in adults. Instrument assisted delivery can be a cause of head trauma in newborns. The goal of this study was to determine if instrument-assisted deliveries influenced the odds of childhood brain tumors in Denmark. MethodsWe conducted a matched case-control study of childhood (<20 years) brain tumors in Denmark born between 1978 and 2013 and diagnosed 1978–2016. A total of 1678 brain tumor cases were identified and 25 controls were matched to each case based on the child’s sex and birth date (N = 40,934). Conditional logistic regression was used to estimate effects (odds ratios (OR) and 95% confidence intervals (95%CI)) for variables of interest. ResultsCompared to children birthed by spontaneous vaginal delivery, children who later developed ependymomas (N = 118) had a greater likelihood of having experienced vacuum assisted deliveries (OR=1.74, 95% CI 1.02–2.96). Forceps use was low, and declined across the study period. We did not observe an overall increase in all CNS tumors (combined) with either vacuum delivery (OR=0.99, 95% CI 0.84–1.18) or forceps delivery (OR=1.26, 95% CI 0.78–2.03). ConclusionOur findings suggest an association between vacuum assisted deliveries and ependymomas.

Childhood head trauma and the risk of childhood brain tumours: A case-control study in Ontario, Canada.

Head trauma in early childhood has been hypothesized as a potential risk factor for childhood brain tumours (CBTs). However, head trauma has not been extensively studied in the context of CBTs and existing studies have yielded conflicting results. A population-based and hospital-based case-control study of children 0 to 15 years with newly diagnosed CBTs from 1997 to 2003 recruited across Ontario through paediatric oncology centres was conducted. Controls were frequency-matched with cases by age, sex and geographical region. The association was assessed based on multivariable logistic regressions, accounting for child's age, sex, ethnicity, highest level of maternal education and maternal pack-years of smoking during the pregnancy. Analyses were conducted separately based on age of first head trauma, sex and histology. A latency period analysis was conducted. Overall, based on 280 cases and 919 controls, CBTs were not significantly associated with previous history of head trauma (OR 1.34, 95% CI 0.96, 1.86), head trauma severity, number of head injuries, or head or neck X-rays or computed tomography (CT) examinations. Results were consistent across sexes and histological subtypes. However, head trauma within the first year of life was significantly associated with CBTs (OR 2.00, 95% CI 1.01, 3.98), but the association diminished when adjusted for X-ray or CT occurring during the same time period (OR 1.62, 95% CI 0.75, 3.49), albeit limited sample size. Overall, no association was observed between head trauma and CBTs among all children, while head trauma occurring within first year of life may warrant further investigation in future research.

Maternal Occupational Exposures and Adverse Pregnancy Outcomes: An Overview of Meta- Analysis

Background: Working pregnant women are exposed to numerous occupational exposures, some of which may adversely affect their reproductive health. We aimed to review the effects of maternal occupational exposures and adverse effects on the infants. Materials and Methods: In this overview, searches were done on the online databases of Scopus, EMBASE, Cochrane, Web of Science and Medline; with no language or time restrictions (up to December 2019) to find studies that assess the relationship between maternal occupational exposures and adverse pregnancy outcomes. Two independent researchers performed the search process and a supervisor judged any disagreement in this regard. Results: Women occupationally exposed to anaesthetic gases had increased risk of spontaneous abortion. Second study reported specific birth defects including limb defects, cleft lip and cleft palate neural tube defects, urinary tract defects and congenital heart defects. In the third study, increased risk of childhood brain tumors was seen following maternal occupational exposures to chlorinated solvents. In the fourth study, a positive relationship between maternal exposures to ambient air pollution with autism spectrum disorder. In the fifth study, a significant relationship between anesthetic gases and congenital malformation, chemotherapy agent and spontaneous abortion and between shift work and spontaneous abortion. In the sixth study, exposure to endocrine-disrupting chemicals, group at work showed an increased risk of LBW with the odds ratio of 1.25, 95% CI: 1.04, 1.49. In the seventh study, exposure to ambient air pollution increases the risk of stillbirth. In eight, a statistically significant association between childhood leukemia and parental occupation. Conclusion: Maternal occupational exposures can be can be leading risk factors for many adverse pregnancy outcomes and birth defects.

Family history of cancer and the risk of childhood brain tumors: a pooled analysis of the ESCALE and ESTELLE studies (SFCE).

Although some specific genetic syndromes such as neurofibromatosis (NF) have been identified as risk factor of childhood brain tumors (CBT), the potential role of inherited susceptibility in CBT has yet to be elucidated. To further investigate this, we conducted a pooled analysis of two nationwide case-control studies ESCALE and ESTELLE. The mothers of 509 CBT cases and 3,102 controls aged under 15years who resided in France at diagnosis/interview, frequency-matched by age and gender, responded to a telephone interview conducted by trained interviewers. Pooled odds ratio (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression. CBT was significantly associated with the family history of cancer in relatives (OR 1.2, 95% CI 1.0-1.5). The OR was slightly higher for maternal relatives than for paternal relatives, and when at least two relatives had a history of cancer. CBT was significantly associated with a family history of brain tumor (OR 2.1, 95% CI 1.3-3.7). This association seemed stronger for first-degree relatives (mother, father, and siblings), for whom, by contrast, no association was seen for cancers other than CBT. No specificity by CBT subtypes or by age of the children were found for any of these findings. Our findings support the hypothesis of a familial susceptibility of CBT, not due to being a known NF carrier.

Perinatal and early life risk factors for childhood brain tumors: Is instrument-assisted delivery associated with higher risk?

BackgroundThe childhood peak of brain tumors suggests that early-life exposures might have a role in their etiology. Hence, we examined in the Greek National Registry for Childhood Hematological Malignancies and Solid tumors (NARECHEM-ST) whether perinatal and early-life risk factors influence the risk of childhood brain tumors. MethodsIn a nationwide case-control study, we included 203 cases (0–14 years) with a diagnosis of brain tumor in NARECHEM-ST (2010–2016) and 406 age-, sex-, and center-matched hospital controls. Information was collected via interviews with the guardians and we analyzed the variables of interest in multivariable conditional logistic regression models. ResultsInstrument-assisted delivery was associated with higher (OR: 7.82, 95%CI: 2.18–28.03), whereas caesarean delivery with lower (OR: 0.67, 95%CI: 0.45-0.99) risk of childhood brain tumors, as compared to spontaneous vaginal delivery. Maternal alcohol consumption during pregnancy (OR: 2.35, 95%CI: 1.45–3.81) and history of living in a farm (OR: 4.98, 2.40–10.32) increased the odds of childhood brain tumors. Conversely, higher birth order was associated with lower risk (OR for 2nd vs. 1st child: 0.60, 95%CI: 0.40-0.89 and OR for 3rd vs. 1st: 0.34, 95%CI: 0.18-0.63). Birth weight, gestational age, parental age, history of infertility, smoking during pregnancy, allergic diseases, and maternal diseases during pregnancy showed no significant associations. ConclusionsPerinatal and early-life risk factors, and specifically indicators of brain trauma, exposure to toxic agents and immune system maturation, might be involved in the pathogenesis of childhood brain tumors. Larger studies should aim to replicate our findings and examine associations with tumor subtypes.

Maternal Use of Household Pesticides during Pregnancy and Risk of Childhood Brain Tumor and Neuroblastoma in the Offspring

Background/Aim: Childhood brain tumor (CBT) and neuroblastoma (NB) are two of the most common solid tumors in childhood. Their etiologies remain still unknown, but the early age at onset suggests t...

Childhood brain tumours, early infections and immune stimulation: A pooled analysis of the ESCALE and ESTELLE case-control studies (SFCE, France)

BackgroundFew studies have investigated whether early infections and factors potentially related to early immune stimulation might be involved in the aetiology of childhood brain tumours (CBT). In this study, we investigated the associations between CBT with early day-care attendance, history of early common infections, atopic conditions (asthma/wheezing, eczema, allergic rhinitis), early farm residence/visits and contact with animals. MethodsWe pooled data from two nationwide French case-control studies, the ESCALE and ESTELLE studies. Children with a CBT diagnosed between 1 and 14 years of age were identified directly from the French National Registry of Childhood Cancers, while population controls were recruited from telephone subscribers. Odds-ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression adjusted for potential confounders. ResultsThe analyses included 469 cases and 2719 controls. We found no association between attending a day-care centre (OR: 0.9, 95%CI: 0.7–1.2) or having had repeated common infections (OR: 0.9, 95%CI: 0.7–1.2) in the first year of life and the risk of CBT. There was also no association with a history of asthma/wheezing (OR: 0.8, 95%CI: 0.56–1.1). Farm visits (OR: 0.6, 95%CI: 0.5–0.8) as well as contact with pets (OR: 0.8, 95%CI: 0.6–1.0) in the first year of life were inversely associated with CBT. ConclusionsOur findings suggest a protective effect of early farm visits and contact with pets, but not with other markers of early immune stimulation. This might be related to immune stimulation but needs further investigation.

Maternal diabetes and incidence of childhood cancer &amp;ndash; a nationwide cohort study and exploratory genetic analysis

BackgroundThe etiology of childhood cancer is not well understood, but may be linked to prenatal and perinatal factors, such as maternal diabetes. However, this association has not been examined in depth. We aimed to determine if maternal diabetes is associated with risk of childhood brain tumor (CBT), leukemia (all types combined and acute lymphoblastic leukemia [ALL] separately), and lymphoma.MethodsAll children born in Sweden between 1973 and 2014 (n=4,239,965) were followed from birth until first cancer diagnosis, age 15 years, or December 31, 2015. Data on maternal diabetes, childhood cancer, and covariates were obtained from nationwide health registers. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated using Cox regression adjusted for potential confounders/mediators. Additionally, we performed an exploratory analysis using results from published genome-wide association studies and functional annotation.ResultsMaternal diabetes was associated with lower risk of CBT (adjusted IRR [95% CI]: 0.56 [0.35–0.91]) and higher risk of leukemia (adjusted IRR: 1.47 [1.13–1.92] for all leukemia combined and 1.64 [1.23–2.18] for ALL). These associations were similar for both maternal type 1 diabetes and gestational diabetes. Associations of five previously identified genetic loci were compatible with a causal effect of diabetes traits on neuroblastoma and common Hodgkin’s lymphoma.ConclusionChildren whose mother had diabetes had lower risk of CBT and higher risk of leukemia, compared with children whose mother did not have diabetes. Our results are compatible with a role of prenatal and perinatal glycemic environment in childhood cancer etiology.

Maternal residential pesticide use during pregnancy and risk of malignant childhood brain tumors: A pooled analysis of the ESCALE and ESTELLE studies (SFCE).

Some previous epidemiological studies have suggested that pesticide exposure during pregnancy may have a possible role in the development of childhood brain tumors (CBT). We pooled data from two French national population-based, case-control studies to investigate the association between maternal residential use of pesticides during pregnancy and the risk of CBT. The mothers of 437 CBT cases and 3,102 controls aged under 15 years who resided in France at diagnosis/interview, frequency-matched by age and gender, answered a structured telephone interview conducted by trained interviewers. Unconditional logistic regression was used to estimate pooled odds ratio (OR) and 95% confidence intervals (95% CI). CBT was significantly associated with the maternal home use of pesticides during pregnancy (OR 1.4, 95% CI 1.2-1.8) and, more specifically, with insecticide (OR 1.4, 1.2-1.8). We could not draw any conclusions about herbicides and/or fungicides because few women used them during pregnancy and most of these mothers also used insecticides. Although potential recall bias cannot be excluded, our findings of this pooled analysis support the hypothesis that residential maternal use of pesticides during pregnancy and particularly insecticides may increase the risk of CBT. Future investigations to verify these findings and to explore for CBT subtypes and dose-response are necessary to have a better understanding of the possible role of pesticides in etiology of CBT.

Parental smoking, maternal alcohol, coffee and tea consumption and the risk of childhood brain tumours: the ESTELLE and ESCALE studies (SFCE, France).

To investigate whether parental smoking around the time of pregnancy or maternal consumption of beverages (alcohol, coffee, or tea) during pregnancy were associated with the risk of CBT. We pooled data from two French national population-based case-control studies with similar designs conducted in 2003-2004 and 2010-2011. The mothers of 510 CBT cases (directly recruited from the national childhood cancer register) and 3,102 controls aged under 15years, frequency matched by age and gender, were interviewed through telephone, which included questions about prenatal parental smoking and maternal consumption of alcohol, coffee and tea. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression, adjusted for age, sex and study of origin. No association was seen between CBT and the mother smoking or drinking alcohol, coffee, or tea during the index pregnancy. The OR between CBT and paternal smoking in the year before birth (as reported by the mother) was 1.25 (95% CI 1.03, 1.52) with an OR of 1.09 (0.99, 1.19) for every 10 cigarettes per day (CPD) smoked. The association between paternal smoking and CBT appeared to be stronger in children diagnosed before the age of five years (OR 1.52, 95% CI 1.14, 2.02) and for astrocytoma (OR 1.86, 95% CI 1.26, 2.74). We found some evidence of a weak association between paternal smoking in the year before the child's birth and CBT, especially astrocytomas. These findings need to be replicated in other samples, using similar classifications of tumour subtypes.

Factors related to pregnancy and birth and the risk of childhood brain tumours: The ESTELLE and ESCALE studies (SFCE, France).

Little is known of the causes of childhood brain tumors (CBT). The aims of this study were to investigate whether extremes of birth weight were associated with increased risk of CBT and whether maternal preconceptional folic acid supplementation or breastfeeding reduced the risk. In addition, other maternal characteristics and birth related factors were also investigated. We pooled data from two French national population-based case-control studies with similar designs conducted in 2003-2004 and 2010-2011. The mothers of 510 CBT cases (directly recruited from the national childhood cancer register) and 3,102 controls aged under 15 years, frequency matched by age and gender did a telephone interview, which focussed on demographic and perinatal characteristics, and maternal life style habits and reproductive history. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression, adjusted for age, sex, study of origin and relevant confounders. No association was found between CBT and birth weight or fetal growth. The use of preconceptional folic acid supplementation was rare (5.3% in cases and 7.8% in controls) and the OR was 0.8 (95% CI 0.5, 1.4). There was no association with breastfeeding, even prolonged (six months or more; OR 1.0, 95% CI 0.8, 1.4). Neither was there any association between CBT and other investigated factors (maternal body mass index, gestational weight gain, congenital abnormality, maternal reproductive history or use of fertility treatments. Although large, this study was underpowered for subtype analyses. Pooling data with other population-based studies may provide further insight into findings by CBT subtypes.

Exposure to pyrethroid pesticides and the risk of childhood brain tumors in East China

Pesticide exposure is hypothesized as one of the risk factors for the development of childhood brain tumors (CBT). This hospital-based case–control study evaluated the association of pyrethroid pesticide exposure with the risk for CBT in a children population in East China. In total, 161 CBT cases and 170 controls were recruited from 2 children's medical centers in Shanghai (Xinhua Hospital and Shanghai Children's Medical Center) between September 2012 and June 2015. The cases and controls were matched for age, sex, and province of residence. Pyrethroid pesticide exposure was evaluated by urinalysis of 3 nonspecific metabolites of pyrethroids (cis-DCCA, trans-DCCA, and 3-PBA) using gas chromatography-mass spectrometry (GC-MS) detection and by administering a questionnaire. Unconditional logistic regression showed that trans-DCCA, 3-PBA, and total metabolites (sum of the 3 metabolites) were positively associated with the increased risk of CBT. Children in the highest quartile had a nearly 3-fold increased risk of CBT compared with those in the lowest quartile after adjusting for confounding factors (trans-DCCA, odds ratio (OR) = 2.58, 95% confidence interval (CI), 1.38–4.80, p = 0.003; 3-PBA, OR = 3.26, 95% CI, 1.73–6.14, p < 0.0001; total metabolites, OR = 3.60, 95% CI, 1.87–6.93, p < 0.0001). We also found that exposure to both mosquitocide and cockroach killer was related to the increased risk of CBT (mosquitocide, OR = 1.68, 95% CI, 1.06–2.67, p = 0.027; cockroach killer, OR = 1.83, 95% CI, 1.13–2.95, p = 0.013). These findings indicate that exposure to pyrethroid pesticides might be associated with increased risk of CBT. Prospective cohort studies with larger sample sizes are required to confirm this conclusion.

Maternal smoking during pregnancy and the risk of childhood brain tumors: Results from a Swedish cohort study

BackgroundTobacco metabolites and carcinogens can be found in placental and umbilical cord tissues of fetuses exposed to maternal smoking. However, studies regarding maternal smoking during pregnancy and childhood brain tumor (CBT) have shown inconsistent results. MethodsAll children born in Sweden between 1983 and 2010 and with information about maternal smoking during pregnancy, obtained from the Swedish Medical Birth Register, were included in this population based cohort study (n=2,577,305). CBT cases were identified from the National Cancer Register. Cox regression models were used to estimate the effect of maternal smoking during pregnancy on the risk of CBTs. ResultsWe identified 1039 cases of CBT in the cohort. Overall, there was little or no effect of maternal smoking during pregnancy on the risk of CBTs. However, in analyses stratified by age at diagnosis and child’s sex, positive associations were found among 5–9 years old children. In this age interval, maternal smoking during pregnancy was associated with an increased risk of all CBTs combined only among male children (RR=1.50, 95% CI 0.96–2.34), while for astrocytoma there was a positive association in both male (RR=2.00, 95% CI 1.02–3.91) and female children (RR=1.80, 95% CI 0.85–3.82). ConclusionResults from this large Swedish cohort study suggest that even though maternal smoking during pregnancy has a limited overall effect on CBTs, it may increase the risk of astrocytomas.

Childhood folate, B6, B12, and food group intake and the risk of childhood brain tumors: results from an Australian case-control study.

The etiology of childhood brain tumors (CBT) is poorly understood, but dietary factors could be involved. In this case-control study of CBT, the possible associations of childhood intake of dietary and supplemental folate, vitamin B6, and vitamin B12 with the risk of CBT were investigated, along with various food groups. Cases diagnosed between 2005 and 2010 were identified from 10 pediatric oncology centers in Australia and controls by nationwide random-digit dialling. For study children of ages 3-14 years, diet in the year before diagnosis (or recruitment) was assessed using food frequency questionnaires. Folate intake was adjusted for bioavailability, and dietary micronutrient intake was energy-adjusted. Micronutrients and food groups were analyzed using logistic regression adjusting for relevant confounders. Principal components analysis was conducted to assess food group intake patterns for analysis. Food and micronutrient data were available for 216 cases and 523 controls. Folate intake was associated with a reduced risk of CBT overall (odds ratio for highest tertile vs. lowest: 0.63, 95% confidence interval 0.41, 0.97) and particularly low-grade gliomas (odds ratio for highest tertile vs. lowest: 0.52, 95% confidence interval 0.29, 0.92). Vitamin B6 and B12 intake was not associated with CBT risk, nor was processed meat. High folate intake during childhood may reduce the risk of CBT. This potentially important finding needs to be corroborated in other studies. If replicated, these results could have important implications for public health recommendations regarding diet during childhood.