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Effects of PCBs, p,p'-DDT, p,p'-DDE, HCB and beta-HCH on thyroid function in preschool children

M Alvarez-Pedrerol1, N Ribas-Fitó, M Torrent

  • 1Centre for Research in Environmental Epidemiology- IMIM, C. Doctor Aiguader 88, 08003 Barcelona, Spain. malvarez1@imim.es

Occupational and Environmental Medicine
|October 16, 2007
PubMed

Insights

Organochlorine compounds (OCs) exposure in preschool children is linked to lower thyroid hormone (TH) levels, specifically total T3. This suggests OCs may impact thyroid function even at low environmental levels.

Area of Science:

  • Environmental Health
  • Endocrinology
  • Pediatric Health

Background:

  • Organochlorine compounds (OCs) are environmental contaminants known to potentially disrupt the endocrine system.
  • Thyroid hormones (THs) are critical for neurodevelopment, making their regulation during early life crucial.
  • Previous research indicates a possible interference of OCs with the thyroid system.

Purpose of the Study:

  • To investigate the association between thyroid function and exposure to various OCs in preschool-aged children.
  • To determine if background levels of OCs correlate with altered thyroid hormone concentrations.

Main Methods:

  • A cohort of 259 preschool children (4 years old) from Menorca, Spain, was studied.
  • Peripheral blood samples were analyzed for concentrations of free thyroxine (free T4), total triiodothyronine (total T3), thyrotropin (TSH), and several OCs.

Main Results:

  • Elevated levels of dichlorodiphenyl trichloroethane (p,p'-DDT), beta-hexachlorocyclohexane (beta-HCH), and specific polychlorinated biphenyls (PCBs: PCB-138, PCB-153, PCB-118) were associated with reduced total T3 levels.
  • Free T4 levels showed an inverse association with PCB-118 exposure.
  • No significant relationship was observed between TSH levels and any of the measured OCs.

Conclusions:

  • Even at typical environmental exposure levels, OCs may negatively impact the thyroid system in young children.
  • Total T3 levels appear particularly sensitive to OC exposure.
  • These findings highlight the potential risks of OCs to thyroid function during critical developmental periods.
Abstract

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