Associations between endocrine disruptor contamination and thyroid hormone homeostasis in Belgian type 1 diabetic children

Purpose: Humans are daily exposed to many environmental pollutants, some of which being suspected to be thyroid disruptors. Some populations could be particularly susceptible to thyroid disruption, such like diabetics due to the well-known relation between the thyroid function and the control of carbohydrate homeostasis by pancreas. Therefore, the aim of this study was to investigate the associations between the exposure to several persistent and non-persistent chemicals and thyroid hormones levels in children with type 1 diabetes. Methods: Blood and urine sample were collected from 54 children diagnosed for type 1 diabetes mellitus. The concentrations of 7 phthalate metabolites, 4 parabens, 7 bisphenols, benzophenone 3 and triclosan were measured in urine, while 15 organochlorine pesticides, 4 polychlorinated biphenyls (PCBs) and 7 perfluoroalkyl substances were analyzed in serum samples. In the same time, the blood levels of free thyroxine (fT4), thyroid stimulating hormone (TSH) and glycated hemoglobin (Hb1Ac) were determined. Results: We highlighted positive associations between serum perfluorohexane sulfonate and urinary monoethylphthalate levels, and TSH level in blood. We also found that PCB 138 was positively associated to fT4 while urinary levels of bisphenol F were negatively correlated to this hormone. Finally, we observed positive associations between Hb1Ac levels and the contamination by PCB 153 and two urinary phthalate metabolites: mono-2-ethyl-5-hydroxyhexyl phthalate and mono-2-ethyl-5-oxoxyhexyl phthalate. Conclusion: Our results showed that our small cohort of children with type 1 diabetes mellitus is potentially susceptible to thyroid disruptions by some pollutants. Moreover, for these children, both di-(2-ethylhexyl) phthalate metabolites would potentially hamper the glucose homeostasis. Nevertheless, additional studies are mandatory to further explore these findings.