title: Maternal exposure to ambient air pollution and risk of early childhood cancers: A population-based study in Ontario, Canada.
abstract: There are increasing concerns regarding the role of exposure to ambient air pollution during pregnancy in the development of early childhood cancers.
  
  
  
  This population based study examined whether prenatal and early life (<1year of age) exposures to ambient air pollutants, including nitrogen dioxide (NO2) and particulate matter with aerodynamic diameters ≤2.5μm (PM2.5), were associated with selected common early childhood cancers in Canada.
  
  
  
  2,350,898 singleton live births occurring between 1988 and 2012 were identified in the province of Ontario, Canada. We assigned temporally varying satellite-derived estimates of PM2.5and land-use regression model estimates of NO2to maternal residences during pregnancy. Incident cases of 13 subtypes of pediatric cancers among children up to age 6 until 2013 were ascertained through administrative health data linkages. Associations of trimester-specific, overall pregnancy and first year of life exposures were evaluated using Cox proportional hazards models, adjusting for potential confounders.
  
  
  
  A total of 2044 childhood cancers were identified. Exposure to PM2.5, per interquartile range increase, over the entire pregnancy, and during the first trimester was associated with an increased risk of astrocytoma (hazard ratio (HR) per 3.9μg/m3=1.38 (95% CI: 1.01, 1.88) and, HR per 4.0μg/m3=1.40 (95% CI: 1.05-1.86), respectively). We also found a positive association between first trimester NO2and acute lymphoblastic leukemia (ALL) (HR=1.20 (95% CI: 1.02-1.41) per IQR (13.3ppb)).
  
  
  
  In this population-based study in the largest province of Canada, results suggest an association between exposure to ambient air pollution during pregnancy, especially in the first trimester and an increased risk of astrocytoma and ALL. Further studies are required to replicate the findings of this study with adjustment for important individual-level confounders.
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ontario, Canada; School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Ontario, Canada. Electronic address: eric.lavigne@hc-sc.gc.ca.
authors.forename: Éric
authors.initials: É
authors.lastname: Lavigne
authors.affiliation: Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada.
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Bélair
authors.affiliation: Surveillance and Epidemiology Division, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Minh T
authors.initials: MT
authors.lastname: Do
authors.affiliation: School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Ontario, Canada; Population Studies Division, Health Canada, Vancouver, British Columbia, Canada.
authors.forename: David M
authors.initials: DM
authors.lastname: Stieb
authors.affiliation: College of Public Health and Human Sciences, Oregon State University, Corvallis, Oregon, USA.
authors.forename: Perry
authors.initials: P
authors.lastname: Hystad
authors.affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Aaron
authors.initials: A
authors.lastname: van Donkelaar
authors.affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Randall V
authors.initials: RV
authors.lastname: Martin
authors.affiliation: Department of Sociology, University of New Brunswick, Fredericton, New Brunswick, Canada.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Crouse
authors.affiliation: Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada; Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Crighton
authors.affiliation: Public Health Ontario, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Air Quality Research Division, Environment Canada, Downsview, Ontario, Canada.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brook
authors.affiliation: Population Studies Division, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Burnett
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ontario, Canada; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Weichenthal
authors.affiliation: Department of Health Sciences, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Villeneuve
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Teresa
authors.initials: T
authors.lastname: To
authors.affiliation: Population Studies Division, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Sabit
authors.initials: S
authors.lastname: Cakmak
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Markey
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Better Outcomes Registry and Network Ontario, Ottawa, Ontario, Canada; Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada.
authors.forename: Abdool S
authors.initials: AS
authors.lastname: Yasseen
authors.affiliation: School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Johnson
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Global Health and Guideline Division, Public Health Agency of Canada, Toronto, Ontario, Canada.
authors.forename: Marianna
authors.initials: M
authors.lastname: Ofner
authors.affiliation: Surveillance and Epidemiology Division, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Lin
authors.initials: L
authors.lastname: Xie
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Better Outcomes Registry and Network Ontario, Ottawa, Ontario, Canada; Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada; Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D009585:Nitrogen Dioxide / Q000633:toxicity; D009864:Ontario / Q000453:epidemiology; D052638:Particulate Matter / Q000633:toxicity; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000453:epidemiology*; D012306:Risk
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D009585:Nitrogen Dioxide
keywords: Air pollution; Childhood cancer; Maternal; Prenatal