title: Investigating the use of hair to assess polybrominated diphenyl ether exposure retrospectively.
abstract: BACKGROUND
  Polybrominated diphenyl ethers (PBDEs) are chemicals that are added to a variety of consumer products as flame-retardants and have been classified as emerging endocrine disruptors. They are persistent and have been detected in humans. Previous studies have suggested that hair is a suitable matrix for examining human exposure to organic pollutants such as PBDEs. It is believed that the majority of exposure is from our indoor environment. The aim of this study was to investigate the changes in PBDE patterns and levels along the hair shaft, by using segmental analysis to retrospectively assess long-term exposure over a 1-year period.
  
  
  METHODS
  Questionnaires and hair samples from 65 women were collected at the Hospital for Sick Children, in Toronto, as part of a larger study. To assess long-term stability, hair samples were separated into 4- and 3-cm segments representing a 1-year period. Hair segments were analyzed for levels of 8 PBDE congeners, BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 on gas chromatography-mass spectrometry (MS). A Friedman test was used to detect the differences in exposure among segments, and factors such as dietary habits, hair care routine, and site of residence were investigated to determine if they might affect hair levels.
  
  
  RESULTS
  A significant increase (P < 0.0001) in total PBDEs was seen among segments moving from proximal (root end) to distal along the hair shaft (median in pg/mg): first (33.3), second (43.0), third (61.6), and fourth (75.5) segments. Significantly lower levels of PBDEs were observed in artificially colored hair samples (P = 0.032), and a significant increase in PBDE levels was observed in women who consumed meat on a daily basis as opposed to weekly consumption (P = 0.040).
  
  
  CONCLUSIONS
  The increase in PBDEs along the hair shaft suggests that hair PBDEs may be influenced by diet and artificial coloring. More work is needed to validate the use of PBDEs in hair as a biomarker of long-term exposure.
authors.affiliation: *Division of Clinical Pharmacology and Toxicology, The Hospital for Sick Children, Toronto; †Department of Pharmacology and Toxicology, University of Toronto; ‡School of Pharmacy, University of Waterloo; §McGill University Health Centre-Montreal Children's Hospital Research Institute; and ¶Ivey Chair in Molecular Toxicology, University of Western Ontario, London, Canada.
authors.forename: Amanda
authors.initials: A
authors.lastname: Carnevale
authors.forename: Katarina
authors.initials: K
authors.lastname: Aleksa
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Goodyer
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
mesh_terms: D000328:Adult; D016477:Artifacts; D004032:Diet; D004781:Environmental Exposure / Q000032:analysis*; D004785:Environmental Pollutants / Q000032:analysis*; D005260:Female; D005411:Flame Retardants / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006197:Hair / Q000737:chemistry*; D006202:Hair Dyes; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D006801:Humans; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D005411:Flame Retardants; D006202:Hair Dyes; D055768:Halogenated Diphenyl Ethers