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

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-years children, while taking puberty into consideration Methods Exposure to 7 PCBs, 4 OCPs and 6 PFASs (in µg/L), and free triiodothyronine (fT3, pg/mL), free thyroxine (fT4, ng/dL) and thyroid-stimulating hormones (TSH, mIU/L) were assessed through blood-serum measurements at age 12 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, 4 and 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), vs 1st tercile). Discussion / Conclusion 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.

Thyroid Hormone Biomonitoring: A Review on Their Metabolism and Machine-Learning Based Analysis on Effects of Endocrine Disrupting Chemicals

“…Specifically, PFOA, PFOS, PFDA, PFNA, and perfluorooctanesulfonamide (FOSA) are linked to increased TSH levels 232,233 (Figure 8a). Moreover, PFDA, PFDoDA, and PFUnDA are related to the decrease in FT3, 185,234 and PFUnDA was found associated with a decrease in TT3 levels 232 (Figures 8c and S2). In studies conducted on zebrafish larvae and GH3 cells, exposure to PFASs, including PFUnDA, perfluorotridecanoic acid (PFTrDA), and 8:8 perfluoroalkyl phosphinic acid (8:8 PFPiA), resulted in an upregulation of TSHβ gene expression, indirectly stimulating TSH synthesis and release.…”

The Association between Long-Term DDT or DDE Exposures and an Altered Sperm Epigenome—a Cross-Sectional Study of Greenlandic Inuit and South African VhaVenda Men

“…This CTQ method and the following details are from Tillaut et al. 58 Two microliters of serum samples were enriched with internal polychlorinated biphenyl (PCB)-labeled standards: PCB , PCB 153- , PCB , PCB , , , , , , Parlar , Parlar , , , and , and alcohol-denatured proteins. Internal standards were provided by the CTQ INSPQ.…”

“…Total cholesterol (TC), free cholesterol (FC), triglycerides and phospholipids levels were also measured in these samples by enzymatic methods (in g/L) and allowed to calculate the total lipid level as . 58 …”

Neuroendocrine Disrupters

“…When investigating the potential endocrine-disrupting activities of chemicals, one approach is to define if some of the molecules released in the environment, from recent or older, acute or chronic, human activity are found in the organisms (human but also wildlife) and whether the presence of the molecule(s) is associated to (neuro)endocrine alterations. The article from Tillaut et al [5] has taken this epidemiological approach and showed some negative correlations between the concentration of some persistent organic pollutants, including Polychlorinated biphenyls (PCBs), organochlorine pesticides, and per- and polyfluoroalkyl substances in 12-year-old children (boys and girls), and the concentration of serum thyroid hormones (TSH, free T3, and free T4). Interestingly, the correlation between persistent organic pollutant exposure and serum thyroid hormones was modified with pubertal stage, especially in boys.…”