title: Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: a Canadian case-control study.
abstract: BACKGROUND
  Endocrine disrupting chemicals and carcinogens, some of which may not yet have been classified as such, are present in many occupational environments and could increase breast cancer risk. Prior research has identified associations with breast cancer and work in agricultural and industrial settings. The purpose of this study was to further characterize possible links between breast cancer risk and occupation, particularly in farming and manufacturing, as well as to examine the impacts of early agricultural exposures, and exposure effects that are specific to the endocrine receptor status of tumours.
  
  
  METHODS
  1005 breast cancer cases referred by a regional cancer center and 1146 randomly-selected community controls provided detailed data including occupational and reproductive histories. All reported jobs were industry- and occupation-coded for the construction of cumulative exposure metrics representing likely exposure to carcinogens and endocrine disruptors. In a frequency-matched case-control design, exposure effects were estimated using conditional logistic regression.
  
  
  RESULTS
  Across all sectors, women in jobs with potentially high exposures to carcinogens and endocrine disruptors had elevated breast cancer risk (OR = 1.42; 95% CI, 1.18-1.73, for 10 years exposure duration). Specific sectors with elevated risk included: agriculture (OR = 1.36; 95% CI, 1.01-1.82); bars-gambling (OR = 2.28; 95% CI, 0.94-5.53); automotive plastics manufacturing (OR = 2.68; 95% CI, 1.47-4.88), food canning (OR = 2.35; 95% CI, 1.00-5.53), and metalworking (OR = 1.73; 95% CI, 1.02-2.92). Estrogen receptor status of tumors with elevated risk differed by occupational grouping. Premenopausal breast cancer risk was highest for automotive plastics (OR = 4.76; 95% CI, 1.58-14.4) and food canning (OR = 5.70; 95% CI, 1.03-31.5).
  
  
  CONCLUSIONS
  These observations support hypotheses linking breast cancer risk and exposures likely to include carcinogens and endocrine disruptors, and demonstrate the value of detailed work histories in environmental and occupational epidemiology.
authors.affiliation: Occupational and Environmental Health Research Group, Centre for Public Health and Population Health Research, University of Stirling, Stirling, Scotland, FK9 4LA, UK. jim.brophy@stir.ac.uk
authors.forename: James T
authors.initials: JT
authors.lastname: Brophy
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Keith
authors.forename: Andrew
authors.initials: A
authors.lastname: Watterson
authors.forename: Robert
authors.initials: R
authors.lastname: Park
authors.forename: Michael
authors.initials: M
authors.lastname: Gilbertson
authors.forename: Eleanor
authors.initials: E
authors.lastname: Maticka-Tyndale
authors.forename: Matthias
authors.initials: M
authors.lastname: Beck
authors.forename: Hakam
authors.initials: H
authors.lastname: Abu-Zahra
authors.forename: Kenneth
authors.initials: K
authors.lastname: Schneider
authors.forename: Abraham
authors.initials: A
authors.lastname: Reinhartz
authors.forename: Robert
authors.initials: R
authors.lastname: Dematteo
authors.forename: Isaac
authors.initials: I
authors.lastname: Luginaah
mesh_terms: D000383:Agriculture; D001943:Breast Neoplasms / Q000453:epidemiology*; D002273:Carcinogens / Q000633:toxicity*; D016022:Case-Control Studies; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D018857:Food Packaging; D006801:Humans; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D010969:Plastics
chemical_list: D002273:Carcinogens; D052244:Endocrine Disruptors; D010969:Plastics