title: Role of Environmental Factors in the Development of Pediatric Eosinophilic Esophagitis.
abstract: BACKGROUND
  Despite accumulating data on the pathogenesis of eosinophilic esophagitis, not much is known about risk factors for the development of the disease. The role of factors such as smoking, breastfeeding, early antibiotic exposure and other factors that have been associated with other allergic diseases has not been well studied in children with eosinophilic esophagitis.
  
  
  OBJECTIVE
  To explore the role of environmental and medication exposures in the development of pediatric eosinophilic esophagitis.
  
  
  METHODS
  We conducted a cross-sectional case-control study, utilizing a parent and child questionnaire and medical chart review. Urine cotinine levels, measured by high-performance liquid chromatography, were obtained as objective evidence for smoking exposure.
  
  
  RESULTS
  One hundred and two children with eosinophilic esophagitis and 167 controls were recruited. The controls were mainly diagnosed with functional gastrointestinal disorders (33%) and gastroesophageal reflux disease (29%). Food allergy, specifically for peanuts and tree nuts, and allergy to pollen, tree, and grass were significantly higher among eosinophilic esophagitis children. Smoking exposure, both primary and secondary, was not associated with pediatric eosinophilic esophagitis when compared to controls (odds ratio 0.96, 95% confidence interval 0.58-1.59). Furthermore, early smoking exposure in the first year of life was higher among controls. Common accepted risk factors for allergy and atopy, such as breastfeeding practices, antibiotics exposure, animals' exposure, and others, were not found to be associated with eosinophilic esophagitis in our study.
  
  
  CONCLUSIONS
  Common risk factors in other allergic and atopic conditions were not found to be associated with eosinophilic esophagitis.
authors.affiliation: Pediatric GI and Nutrition, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy (ECHA), 4th Floor, Room 4-579, 11405 - 87th Avenue, Edmonton, AB, T6G 1C9, Canada. slae@ualberta.ca.
authors.forename: Mordechai
authors.initials: M
authors.lastname: Slae
authors.affiliation: Pediatric GI and Nutrition, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy (ECHA), 4th Floor, Room 4-579, 11405 - 87th Avenue, Edmonton, AB, T6G 1C9, Canada. Rabin.persad@albertahealthservices.ca.
authors.forename: Rabin
authors.initials: R
authors.lastname: Persad
authors.affiliation: Pediatric GI and Nutrition, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy (ECHA), 4th Floor, Room 4-579, 11405 - 87th Avenue, Edmonton, AB, T6G 1C9, Canada. ajleung@ualberta.ca.
authors.forename: Aldrich Jing-Tao
authors.initials: AJ
authors.lastname: Leung
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 2-142H Katz Group Centre, 87 Ave and 114 St, Edmonton, AB, T6G 2J7, Canada. gabr@ualberta.ca.
authors.forename: Raniah
authors.initials: R
authors.lastname: Gabr
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 2-142H Katz Group Centre, 87 Ave and 114 St, Edmonton, AB, T6G 2J7, Canada. dbrocks@ualberta.ca.
authors.forename: Dion
authors.initials: D
authors.lastname: Brocks
authors.affiliation: Pediatric GI and Nutrition, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy (ECHA), 4th Floor, Room 4-579, 11405 - 87th Avenue, Edmonton, AB, T6G 1C9, Canada. hien.huynh@ualberta.ca.
authors.forename: Hien Quoc
authors.initials: HQ
authors.lastname: Huynh
mesh_terms: D017668:Age of Onset; D015415:Biomarkers / Q000652:urine; D001942:Breast Feeding; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D003367:Cotinine / Q000652:urine; D003430:Cross-Sectional Studies; D004777:Environment; D057765:Eosinophilic Esophagitis / Q000175:diagnosis / Q000453:epidemiology* / Q000652:urine; D005260:Female; D006306:Health Surveys; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
chemical_list: D015415:Biomarkers; D014028:Tobacco Smoke Pollution; D003367:Cotinine
keywords: Allergy; Eosinophilic esophagitis; Risk factors; Tobacco smoking; Urine cotinine