title: A systematic review of the risk factors associated with the onset and progression of primary brain tumours.
abstract: The overall aim of this systematic review was to identify risk factors for onset and natural progression, which were shown to increase, decrease, or have a null association with risk of primary brain tumour. For onset, the project was separated into two phases. The first phase consisted of a systematic search of existing systematic reviews and meta-analyses. Moderate to high methodological quality reviews were incorporated and summarized with relevant observational studies published since 2010, identified from a systematic search performed in phase 2. For natural progression, only the first phase was conducted. Standard systematic review methodology was utilized. Based on this review, various genetic variants, pesticide exposures, occupational farming/hairdressing, cured meat consumption and personal hair dye use appear to be associated with increased risk of onset amongst adults. The specific EGF polymorphsm 61-A allele within Caucasian populations and having a history of allergy was associated with a decreased risk. For progression, M1B-1 antigen was shown to increase the risk. High birth weight, pesticide exposure (childhood exposure, and parental occupational exposure) and maternal consumption of cured meat during pregnancy may also increase the risk of onset of childhood brain tumours. Conversely, maternal intake of pre-natal supplements (folic acid) appeared to decrease risk. Children with neurofibromatosis 2 were considered to have worse overall and relapse free survival compared to neurofibromatosis 1, as were those children who had grade III tumours compared to lesser grades.
authors.affiliation: School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, ON, Canada. Electronic address: pquac075@uottawa.ca.
authors.forename: Pauline
authors.initials: P
authors.lastname: Quach
authors.affiliation: Department of Family Medicine, McGill University, Montreal, QC, Canada.
authors.forename: Reem
authors.initials: R
authors.lastname: El Sherif
authors.affiliation: Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Gomes
authors.affiliation: School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, ON, Canada; McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada; Risk Sciences International, Ottawa, ON, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewksi
mesh_terms: D017668:Age of Onset; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000209:etiology* / Q000235:genetics; D018450:Disease Progression; D004815:Epidermal Growth Factor / Q000235:genetics; D006801:Humans; D019394:Ki-67 Antigen / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009456:Neurofibromatosis 1 / Q000235:genetics; D016518:Neurofibromatosis 2 / Q000235:genetics; D010575:Pesticides / Q000633:toxicity; D012307:Risk Factors; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics
chemical_list: D019394:Ki-67 Antigen; D010575:Pesticides; D004815:Epidermal Growth Factor; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C497446:VHL protein, human
keywords: Adult; Brain tumours; Child; Onset; Progression; Risk factors; Systematic review