title: Association between perfluoroalkyl substances and thyroid stimulating hormone among pregnant women: a cross-sectional study.
abstract: BACKGROUND
  Perfluoroalkyl substances (PFASs) are a group of highly persistent chemicals that are widespread contaminants in wildlife and humans. Exposure to PFAS affects thyroid homeostasis in experimental animals and possibly in humans. The objective of this study was to examine the association between plasma concentrations of PFASs and thyroid stimulating hormone (TSH) among pregnant women.
  
  
  METHODS
  A total of 903 pregnant women who enrolled in the Norwegian Mother and Child Cohort Study from 2003 to 2004 were studied. Concentrations of thirteen PFASs and TSH were measured in plasma samples collected around the 18th week of gestation. Linear regression models were used to evaluate associations between PFASs and TSH.
  
  
  RESULTS
  Among the thirteen PFASs, seven were detected in more than 60% of samples and perfluorooctane sulfonate (PFOS) had the highest concentrations (median, 12.8 ng/mL; inter-quartile range [IQR], 10.1 -16.5 ng/mL). The median TSH concentration was 3.5 (IQR, 2.4 - 4.8) μIU/mL. Pregnant women with higher PFOS had higher TSH levels. After adjustment, with each 1 ng/mL increase in PFOS concentration, there was a 0.8% (95% confidence interval: 0.1%, 1.6%) rise in TSH. The odds ratio of having an abnormally high TSH, however, was not increased, and other PFASs were unrelated to TSH.
  
  
  CONCLUSIONS
  Our results suggest an association between PFOS and TSH in pregnant women that is small and may be of no clinical significance.
authors.affiliation: Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, USA. wangy13@niehs.nih.gov.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Anne P
authors.initials: AP
authors.lastname: Starling
authors.forename: Line S
authors.initials: LS
authors.lastname: Haug
authors.forename: Merete
authors.initials: M
authors.lastname: Eggesbo
authors.forename: Georg
authors.initials: G
authors.lastname: Becher
authors.forename: Cathrine
authors.initials: C
authors.lastname: Thomsen
authors.forename: Gregory
authors.initials: G
authors.lastname: Travlos
authors.forename: Debra
authors.initials: D
authors.lastname: King
authors.forename: Jane A
authors.initials: JA
authors.lastname: Hoppin
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Rogan
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Longnecker
mesh_terms: D000293:Adolescent; D000328:Adult; D000473:Alkanes / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006801:Humans; D007118:Immunoassay; D016014:Linear Models; D009664:Norway; D016017:Odds Ratio; D011247:Pregnancy; D053719:Tandem Mass Spectrometry; D013972:Thyrotropin / Q000097:blood*; D055815:Young Adult
chemical_list: D000473:Alkanes; D004785:Environmental Pollutants; D005466:Fluorocarbons; D013972:Thyrotropin