title: Traffic-related air pollution and childhood acute leukemia in Oklahoma.
abstract: While many studies have evaluated the association between acute childhood leukemia and environmental factors, knowledge is limited. Ambient air pollution has been classified as a Group 1 carcinogen, but studies have not established whether traffic-related air pollution is associated with leukemia. The goal of our study was to determine if children with acute leukemia had higher odds of exposure to traffic-related air pollution at birth compared to controls.
  
  
  
  We conducted a case-control study using the Oklahoma Central Cancer Registry to identify cases of acute leukemia in children diagnosed before 20 years of age between 1997 and 2012 (n=307). Controls were selected from birth certificates and matched to cases on week of birth (n=1013). Using a novel satellite-based land-use regression model of nitrogen dioxide (NO2) and estimating road density based on the 2010 US Census, we evaluated the association between traffic-related air pollution and childhood leukemia using conditional logistic regression.
  
  
  
  The odds of exposure to the fourth quartile of NO2 (11.19-19.89ppb) were similar in cases compared to controls after adjustment for maternal education (OR: 1.08, 95% CI: 0.75, 1.55). These estimates were stronger among children with acute myeloid leukemia (AML) than acute lymphoid leukemia, with a positive association observed among urban children with AML (4th quartile odds ratio: 5.25, 95% confidence interval: 1.09, 25.26). While we observed no significant association with road density, male cases had an elevated odds of exposure to roads at 500m from the birth residence compared to controls (OR: 1.39, 95% CI: 0.93, 2.10), which was slightly attenuated at 750m.
  
  
  
  Although we observed no association overall between NO2 or road density, this was the first study to observe an elevated odds of exposure to NO2 among children with AML compared to controls suggesting further exploration of traffic-related air pollution and AML is warranted.
authors.affiliation: Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, 801 NE 13th St., CHB 309, Oklahoma City, OK 73104, USA. Electronic address: amanda-janitz@ouhsc.edu.
authors.forename: Amanda E
authors.initials: AE
authors.lastname: Janitz
authors.affiliation: Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, 801 NE 13th St., CHB 309, Oklahoma City, OK 73104, USA. Electronic address: janis-campbell@ouhsc.edu.
authors.forename: Janis E
authors.initials: JE
authors.lastname: Campbell
authors.affiliation: Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, 1681 Campus Delivery, Fort Collins, CO 80523, USA. Electronic address: sheryl.magzamen@colostate.edu.
authors.forename: Sheryl
authors.initials: S
authors.lastname: Magzamen
authors.affiliation: School of Nursing and Allied Health Sciences, Southwestern Oklahoma State University, 100 E. Campus Dr., Weatherford, OK 73096, USA. Electronic address: anne.pate@swosu.edu.
authors.forename: Anne
authors.initials: A
authors.lastname: Pate
authors.affiliation: Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, 801 NE 13th St., CHB 309, Oklahoma City, OK 73104, USA. Electronic address: julie-stoner@ouhsc.edu.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Stoner
authors.affiliation: Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, 801 NE 13th St., CHB 309, Oklahoma City, OK 73104, USA. Electronic address: jennifer-peck@ouhsc.edu.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Peck
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007938:Leukemia / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D018986:Motor Vehicles; D009585:Nitrogen Dioxide / Q000032:analysis*; D016017:Odds Ratio; D009825:Oklahoma / Q000453:epidemiology; D001335:Vehicle Emissions; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide
keywords: Air pollution; Children; Leukemia; Nitrogen dioxide; Traffic