title: Cord blood thyroid tests in boys born with and without cryptorchidism: correlations with birth parameters and in utero xenobiotics exposure.
abstract: BACKGROUND
  In utero exposure to environmental chemicals can result in reproductive toxicity via endocrine disruption mechanisms. Whether some of those contaminants also have an impact on fetal thyroid function or pathways, and, thus, potentially on neuropsychological development, is still debated.
  
  
  METHODS
  We used samples from a cord blood (CB) and milk bank, established for a research on cryptorchidism and xenobiotic exposure to compounds known for their anti-androgenic and/or estrogenic activity, to study CB thyroid tests and their correlation with CB and milk xenobiotics concentrations in boys born in Nice area.
  
  
  RESULTS
  No difference was found in thyroid tests between 60 cryptorchid boys and 76 matched controls (median thyroid stimulating hormone 5.97 vs. 6.55 mUI/L, free thyroxine [fT4] 13.1 vs. 12.9 pmol/L, free triiodothyronine [fT3] 1.9 vs. 2.1 pmol/L), with no influence of season of birth, gestational age, maternal smoking, or mode of delivery (except for higher fT4 in control boys born vaginally). FT4 was correlated with fetal growth only in cryptorchid boys. Since we had previously shown differences between cryptorchid and controls exposure, we studied correlations of thyroid tests with xenobiotics in control boys only. All tested CB or maternal milk was contaminated by one or more selected xenobiotics, mainly polychlorinated biphenyls (PCBs), dichloro diphenyl dichloroethylène (DDE), dibutylphthalate, hexachlorobenzene, and bisphenol A. We found a significant negative correlation between fT4 and concentrations of PCB118, PC180, and DDE in milk (respectively r = -0.342, p < 0.03, r = -0.296, p = 0.031, r = -0.315, p = 0.016), persisting after adjustment for mode of delivery. There was a significant positive correlation of fT3 with milk concentrations of PCB138, PCB153, ΣPCB, and dibutylphthalate (respectively r = 0.31, p = 0.016, r = 0.28, p = 0.029; r = 0.34, p = 0.0079 and r = 0.272, p = 0.0295), with a trend for PCB180 (r = 0.259, p = 0.061). There was no correlation of thyroid stimulating hormone with any of the measured xenobiotics, except for a weak negative trend with CB bisphenol A (r = -0.25, p = 0.077).
  
  
  CONCLUSIONS
  CB thyroid tests are within normal range in cryptorchid boys, similar to controls. Our data in controls suggest a possible weak correlation between in utero exposure to some xenobiotics (PCBs, DDE) and fT3 and fT4 CB concentrations, with usually negative correlations with fT4 and positive with fT3 concentrations, which we speculate could suggest an impact on deiodinases.
authors.affiliation: Department of Endocrinology, University Hospital Center (CHU) of Nice, Nice, France. brucker-davis.f@chu-nice.fr
authors.forename: Francoise
authors.initials: F
authors.lastname: Brucker-Davis
authors.forename: Patricia
authors.initials: P
authors.lastname: Ferrari
authors.forename: Mireille
authors.initials: M
authors.lastname: Boda-Buccino
authors.forename: Kathy
authors.initials: K
authors.lastname: Wagner-Mahler
authors.forename: Patricia
authors.initials: P
authors.lastname: Pacini
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Gal
authors.forename: Pierre
authors.initials: P
authors.lastname: Azuar
authors.forename: Patrick
authors.initials: P
authors.lastname: Fenichel
mesh_terms: D016022:Case-Control Studies; D003456:Cryptorchidism / Q000097:blood* / Q000139:chemically induced; D003633:Dichlorodiphenyl Dichloroethylene / Q000009:adverse effects / Q000032:analysis; D052244:Endocrine Disruptors / Q000009:adverse effects / Q000032:analysis; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005602:France; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D008895:Milk, Human / Q000737:chemistry; D011078:Polychlorinated Biphenyls / Q000009:adverse effects / Q000032:analysis; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood / Q000139:chemically induced; D015995:Prevalence; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*; D015262:Xenobiotics / Q000009:adverse effects* / Q000032:analysis
chemical_list: D052244:Endocrine Disruptors; D015262:Xenobiotics; D014284:Triiodothyronine; D003633:Dichlorodiphenyl Dichloroethylene; D013972:Thyrotropin; D011078:Polychlorinated Biphenyls; D013974:Thyroxine