Persistent Organic Pollutant Exposure and Thyroid Function among 12-Year-Old Children

Neuroendocrinology. 2023;113(12):1232-1247. doi: 10.1159/000528631. Epub 2022 Dec 9.

Abstract

Introduction: Polychlorobiphenyls (PCBs), organochlorine pesticides (OCPs), and per- and polyfluoroalkyl substances (PFASs) are persistent organic pollutants (POPs) having numerous toxicological properties, including thyroid endocrine disruption. Our aim was to assess the impact of POPs on thyroid hormones among 12-year-old children, while taking puberty into consideration.

Methods: Exposure to 7 PCBs, 4 OCPs, and 6 PFASs (in µg/L), and free tri-iodothyronine (fT3, pg/mL), free thyroxine (fT4, ng/dL), and thyroid-stimulating hormones (TSH, mIU/L) were assessed through blood-serum measurements at age 12 years in 249 boys and 227 girls of the PELAGIE mother-child cohort (France). Pubertal status was clinically rated using the Tanner stages. For each POP, associations were estimated using linear regression, adjusted for potential confounders.

Results: Among boys, hexachlorobenzene and perfluorodecanoic acid were associated with decreased fT3 (log-scale; β [95% confidence interval] = -0.07 [-0.12,-0.02] and β = -0.03 [-0.06,-0.00], respectively). Intermediate levels of perfluorohexanesulfonic acid (PFHxS) and PCB180 were associated, respectively, with increased and decreased fT4. After stratification on pubertal status, PCBs and OCPs were associated with decreased TSH only in the more advanced Tanner stages (3-5) and with decreased fT3 among early Tanner stages (1-2). Among girls, PFHxS was associated with decreased TSH (log-scale; β = -0.15 [-0.29,-0.00]), and perfluorooctanoic acid was associated with decreased fT3 (β2nd_tercile = -0.06 [-0.10,-0.03] and β3rd_tercile = -0.04 [-0.08,-0.00], versus. 1st tercile).

Discussion: This cross-sectional study highlights associations between some POPs and thyroid function disruption, which appears consistent with the literature. Considering that the associations were sex-specific and moderated by pubertal status in boys, complex endocrine interactions are likely involved.

Keywords: Adolescence; Per- and polyfluoroalkyl substances; Persistent organic pollutant; Thyroid function.

MeSH terms

  • Child
  • Cross-Sectional Studies
  • Environmental Pollutants* / toxicity
  • Female
  • Fluorocarbons* / toxicity
  • Humans
  • Hydrocarbons, Chlorinated*
  • Male
  • Persistent Organic Pollutants
  • Polychlorinated Biphenyls*
  • Thyroid Gland
  • Thyroid Hormones
  • Thyrotropin

Substances

  • Persistent Organic Pollutants
  • Polychlorinated Biphenyls
  • Thyroid Hormones
  • Environmental Pollutants
  • Thyrotropin
  • Hydrocarbons, Chlorinated
  • Fluorocarbons
  • perfluorohexanesulfonic acid

Grants and funding

The PELAGIE cohort has been funded by Inserm (since the beginning), the French Ministries of Health (2003–2004), Labor (2002–2003), and Research (ATC 2003–2004), the French National Institute for Public Health Surveillance (InVS, 2002–2006), the National Agency for Research (ANR, 2005–2008, 2010–2012, 2015–2019), the French Agency for Environmental Health Safety (Afsset/ANSES, 2007–2009, 2009–2012), the French Agency for Drug Safety (2013–2017), the Fondation de France (2014–2017, 2015–2018, 2017–2021), the French Ministry of Ecology (PNRPE 2014–2016), the Research Institute of Public Health (IResP 2011–2014), and the following European programs: Hi-WATE 2007–2009, ENRIECO 2008–2010, and OBERON 2019–2023. This research is part of a PhD project funded by the French network of doctoral programs, coordinated by EHESP French School of Public Health.