title: Thyroid function and perfluoroalkyl acids in children living near a chemical plant.
abstract: BACKGROUND
  Animal studies suggest that some perfluoroalkyl acids (PFAAs), including perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and perfluorononanoic acid (PFNA) may impair thyroid function. Epidemiological findings, mostly related to adults, are inconsistent.
  
  
  OBJECTIVE
  We investigated whether concentrations of PFAAs were associated with thyroid function among 10,725 children (1-17 years of age) living near a Teflon manufacturing facility in the Mid-Ohio Valley (USA).
  
  
  METHODS
  Serum levels of thyroid-stimulating hormone (TSH), total thyroxine (TT4), and PFAAs were measured during 2005-2006, and information on diagnosed thyroid disease was collected by questionnaire. Modeled in utero PFOA concentrations were based on historical information on PFOA releases, environmental distribution, pharmacokinetic modeling, and residential histories. We performed multivariate regression analyses.
  
  
  RESULTS
  Median concentrations of modeled in utero PFOA and measured serum PFOA, PFOS, and PFNA were 12, 29, 20, and 1.5 ng/mL, respectively. The odds ratio for hypothyroidism (n = 39) was 1.54 [95% confidence interval (CI): 1.00, 2.37] for an interquartile range (IQR) contrast of 13 to 68 ng/mL in serum PFOA measured in 2005-2006. However, an IQR shift in serum PFOA was not associated with TSH or TT4 levels in all children combined. IQR shifts in serum PFOS (15 to 28 ng/mL) and serum PFNA (1.2 to 2.0 ng/mL) were both associated with a 1.1% increase in TT4 in children 1-17 years old (95% CIs: 0.6, 1.5 and 0.7, 1.5 respectively).
  
  
  CONCLUSIONS
  This is the first large-scale report in children suggesting associations of serum PFOS and PFNA with thyroid hormone levels and of serum PFOA and hypothyroidism.
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, London, United Kingdom. maria-jose.lopez@lshtm.ac.uk
authors.forename: Maria-Jose
authors.initials: MJ
authors.lastname: Lopez-Espinosa
authors.forename: Debapriya
authors.initials: D
authors.lastname: Mondal
authors.forename: Ben
authors.initials: B
authors.lastname: Armstrong
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bloom
authors.forename: Tony
authors.initials: T
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D017738:Alkanesulfonic Acids / Q000097:blood; D002210:Caprylates / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006801:Humans; D007223:Infant; D008297:Male; D011795:Surveys and Questionnaires; D013961:Thyroid Gland / Q000378:metabolism*; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D004785:Environmental Pollutants; D005466:Fluorocarbons; D013963:Thyroid Hormones; D013972:Thyrotropin; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid; D013974:Thyroxine