title: Association between thyroid hormone levels and 4,4'-DDE concentrations in pregnant women (Valencia, Spain).
abstract: BACKGROUND
  Several epidemiological studies have reported that some organochlorine compounds (OCs), such as polychlorobiphenyls (PCBs) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4'-DDE), may alter thyroid function.
  
  
  OBJECTIVE
  The aim of the present study was to investigate the association of maternal serum OC concentrations of 4,4'-DDE and the sum of seven PCB congeners (PCB 28, 52, 101, 118, 138, 153, and 180) with thyroid hormone (TH) status.
  
  
  METHODS
  We measured OC concentrations in 157 maternal serum samples at 12 weeks of pregnancy in a cohort from Valencia (Spain). Thyroid-stimulating hormone (TSH), total triiodothyronine (TT3), and free thyroxine (FT4) were measured as biomarkers of thyroid function in the same samples. Linear and logistic regression analyses were performed between OCs and TH levels, and variables were log transformed.
  
  
  RESULTS
  Mothers with higher levels of 4,4'-DDE had higher odds of having TSH levels >2.5 mIU/L (OR=2.53; 95% CI=1.36; 4.73; p=0.004), and we found a significant negative association between serum 4,4'-DDE concentrations and FT4 levels (beta=-0.03; 95% CI=-0.05; 0.00; p=0.050) after adjustment for covariates and total lipids. No association was found between sum of PCBs and TH levels.
  
  
  CONCLUSIONS
  Serum concentrations of 4,4'-DDE were associated with increased TSH and reduced FT4 but not TT3 levels. Our results suggest that some environmental chemicals may interfere with the thyroid system of pregnant women. The major role that maternal THs may play in fetal neurodevelopment makes these findings especially relevant.
authors.affiliation: Unit of Epidemiologic and Statistics, Valencian School of Health Studies, Conselleria de Sanidad, Juan de Garay 21, Valencia 46017, Spain. lopez_josesp@gva.es
authors.forename: Maria-Jose
authors.initials: MJ
authors.lastname: Lopez-Espinosa
authors.forename: Esther
authors.initials: E
authors.lastname: Vizcaino
authors.forename: Mario
authors.initials: M
authors.lastname: Murcia
authors.forename: Sabrina
authors.initials: S
authors.lastname: Llop
authors.forename: Mercedes
authors.initials: M
authors.lastname: Espada
authors.forename: Vicente
authors.initials: V
authors.lastname: Seco
authors.forename: Alfredo
authors.initials: A
authors.lastname: Marco
authors.forename: Marisa
authors.initials: M
authors.lastname: Rebagliato
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003633:Dichlorodiphenyl Dichloroethylene / Q000009:adverse effects / Q000097:blood*; D005260:Female; D047109:Fetal Development / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007306:Insecticides / Q000009:adverse effects / Q000097:blood; D016014:Linear Models; D016015:Logistic Models; D018811:Maternal Exposure / Q000009:adverse effects; D016017:Odds Ratio; D011078:Polychlorinated Biphenyls / Q000009:adverse effects / Q000097:blood*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood; D011297:Prenatal Exposure Delayed Effects / Q000097:blood* / Q000453:epidemiology; D013030:Spain / Q000453:epidemiology; D013961:Thyroid Gland / Q000187:drug effects* / Q000503:physiopathology; D013963:Thyroid Hormones / Q000097:blood* / Q000502:physiology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007306:Insecticides; D013963:Thyroid Hormones; D014284:Triiodothyronine; D003633:Dichlorodiphenyl Dichloroethylene; D013972:Thyrotropin; D011078:Polychlorinated Biphenyls; D013974:Thyroxine