title: Case-control study of breast cancer and exposure to synthetic environmental chemicals among Alaska Native women.
abstract: Exposure to environmental chemicals may impair endocrine system function. Alaska Native (AN) women may be at higher risk of exposure to these endocrine disrupting chemicals, which may contribute to breast cancer in this population.
  
  
  
  To measure the association between exposure to select environmental chemicals and breast cancer among AN women.
  
  
  
  A case-control study of 170 women (75 cases, 95 controls) recruited from the AN Medical Center from 1999 to 2002. Participants provided urine and serum samples. Serum was analyzed for 9 persistent pesticides, 34 polychlorinated biphenyl (PCB) congeners, and 8 polybrominated diethyl ether (PBDE) congeners. Urine was analyzed for 10 phthalate metabolites. We calculated geometric means (GM) and compared cases and controls using logistic regression.
  
  
  
  Serum concentrations of most pesticides and 3 indicator PCB congeners (PCB-138/158; PCB-153, PCB-180) were lower in case women than controls. BDE-47 was significantly higher in case women (GM=38.8 ng/g lipid) than controls (GM=25.1 ng/g lipid) (p=0.04). Persistent pesticides, PCBs, and most phthalate metabolites were not associated with case status in univariate logistic regression. The odds of being a case were higher for those with urinary mono-(2-ethylhexyl) phthalate (MEHP) concentrations that were above the median; this relationship was seen in both univariate (OR 2.16, 95% CI 1.16-4.05, p=0.02) and multivariable (OR 2.43, 95% CI 1.13-5.25, p=0.02) logistic regression. Women with oestrogen receptor (ER)-/progesterone receptor (PR)-tumour types tended to have higher concentrations of persistent pesticides than did ER+/PR+ women, although these differences were not statistically significant.
  
  
  
  Exposure to the parent compound of the phthalate metabolite MEHP may be associated with breast cancer. However, our study is limited by small sample size and an inability to control for the confounding effects of body mass index. The association between BDE-47 and breast cancer warrants further investigation.
authors.affiliation: Health Studies Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA; aoh8@cdc.gov.
authors.forename: Adrianne K
authors.initials: AK
authors.lastname: Holmes
authors.affiliation: Office of Alaska Native Health Research, Division of Community Health Service, Alaska Native Tribal Health Consortium, Anchorage, AK, USA.
authors.forename: Kathryn R
authors.initials: KR
authors.lastname: Koller
authors.affiliation: Health Studies Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Kieszak
authors.affiliation: Organic Analytical Toxicology Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sjodin
authors.affiliation: Organic Analytical Toxicology Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
authors.affiliation: Pathology Department, Alaska Native Tribal Health Consortium, Alaska Native Medical Center, Anchorage, AK, USA.
authors.forename: Frank D
authors.initials: FD
authors.lastname: Sacco
authors.affiliation: Pathology Department, Alaska Native Tribal Health Consortium, Alaska Native Medical Center, Anchorage, AK, USA.
authors.forename: D Wayne
authors.initials: DW
authors.lastname: Varner
authors.affiliation: Office of Alaska Native Health Research, Division of Community Health Service, Alaska Native Tribal Health Consortium, Anchorage, AK, USA.
authors.forename: Anne P
authors.initials: AP
authors.lastname: Lanier
authors.affiliation: Vector-Borne, and Enteric Diseases, National Center for Zoonotic, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Carol H
authors.initials: CH
authors.lastname: Rubin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000413:Alaska / Q000453:epidemiology; D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D016022:Case-Control Studies; D004781:Environmental Exposure / Q000009:adverse effects; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000737:chemistry*; D005260:Female; D055768:Halogenated Diphenyl Ethers / Q000009:adverse effects; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D010795:Phthalic Acids / Q000009:adverse effects; D011078:Polychlorinated Biphenyls / Q000009:adverse effects; D044382:Population Groups / Q000706:statistics & numerical data*; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment
chemical_list: D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; D010795:Phthalic Acids; C511295:2,2',4,4'-tetrabromodiphenyl ether; C032279:phthalic acid; D011078:Polychlorinated Biphenyls
keywords: Alaska Native; breast cancer; environmental chemical exposure; persistent pesticides; phthalates; polychlorinated biphenyl ethers