title: Exposure to Polybrominated Diphenyl Ethers (PBDEs) and Hypothyroidism in Canadian Women.
abstract: BACKGROUND
  Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in a wide range of products, resulting in widespread human exposure. Epidemiological studies in some populations reported exposure to PBDEs and thyroid hormone levels but little epidemiological data are available among women from the general population.
  
  
  OBJECTIVE
  The objective of the study was to examine the association of PBDEs with hypothyroidism.
  
  
  METHODS
  This was a cross-sectional analysis of the 2007-2009 Canadian Health Measures Survey.
  
  
  METHODS
  A total of 745 women representative of Canadian women aged 30-79 years participated in the study. Main Outcome and Methods: We estimated the prevalence ratios (PRs) for hypothyroidism in relation to plasma concentrations of BDE-47, -99, -100, and -153 and their sum (ΣPBDEs). Women were identified as cases if they reported a doctor-diagnosed thyroid condition and underwent thyroid hormone replacement therapy (n = 90).
  
  
  RESULTS
  Higher plasma levels of brominated diphenyl ether (BDE)-47 and -100 and ΣPBDEs were associated with an increased prevalence of hypothyroidism. The PR for a 10-fold increase in ΣPBDEs was 1.7 (95% confidence interval [CI] 1.0, 3.0). Associations were consistently higher among women aged 30-50 years than among those 51-79 years for ΣPBDEs and the other PBDE congeners, although the interaction was significant only for BDE-100. For instance, in the younger age group, women with detectable levels of BDE-100 had a PR of 3.8 (95% CI 1.2, 12.3) compared with women with undetectable levels; the corresponding PR in the older age group was 1.2 (95% CI 0.6, 2.3). No association was observed for BDE-99 and -153.
  
  
  CONCLUSIONS
  Plasma PBDE levels were associated with an increased prevalence of hypothyroidism in Canadian women aged 30-50 years. Although the cross-sectional design of the study limits inferences of causality, these findings have important implications, given the key role of thyroid hormones in several biological mechanisms during reproductive age.
authors.affiliation: Department of Environmental and Occupational Health (Y.O., M.F.B.), Université de Montréal, and Centre Hospitalier de l'Université Sainte-Justine Mother and Child University Hospital Research Center (Y.O., M.F.B.), Montréal, Canada H3T 1A8; and Department of Epidemiology, Biostatistics and Occupational Health (J.C.), McGill University, Montréal, Canada H3A 1A2.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Oulhote
authors.affiliation: Department of Environmental and Occupational Health (Y.O., M.F.B.), Université de Montréal, and Centre Hospitalier de l'Université Sainte-Justine Mother and Child University Hospital Research Center (Y.O., M.F.B.), Montréal, Canada H3T 1A8; and Department of Epidemiology, Biostatistics and Occupational Health (J.C.), McGill University, Montréal, Canada H3A 1A2.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chevrier
authors.affiliation: Department of Environmental and Occupational Health (Y.O., M.F.B.), Université de Montréal, and Centre Hospitalier de l'Université Sainte-Justine Mother and Child University Hospital Research Center (Y.O., M.F.B.), Montréal, Canada H3T 1A8; and Department of Epidemiology, Biostatistics and Occupational Health (J.C.), McGill University, Montréal, Canada H3A 1A2.
authors.forename: Maryse F
authors.initials: MF
authors.lastname: Bouchard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D002648:Child; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D055768:Halogenated Diphenyl Ethers / Q000097:blood / Q000633:toxicity*; D006306:Health Surveys; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced* / Q000453:epidemiology*; D008875:Middle Aged; D015995:Prevalence; D012959:Socioeconomic Factors; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; C086401:pentabromodiphenyl ether