Endocrine Abstracts

Introduction: Autoimmune thyroiditis (AIT), also called Hashimoto thyroiditis or chronic lymphocytic thyroiditis is characterized by destruction of the thyroid gland involving apoptosis of thyroid epithelial cells. It usually presents as euthyroidism or subclinically hypothyroidism, rarely as overt hypothyroidism. The cause of Hashimoto’s thyroiditis is thought to be a combination of genetic susceptibility and environmental factors. Bisphenol A (BPA), an endocrine-disrupting chemical, is the main component of polycarbonate plastics and is one of the highest volume chemicals in production today. The human population is widely and continuously exposed to BPA through food, drinking water, dermal exposures, and inhalation of dusts. Aim of this study is to evaluate circulating levels of BPA in patients with euthyroid AIT.

Material and methods: Circulating levels of BPA were measured in 20 consecutive patients newly diagnosed with euthyroid AIT and 22 euthyroid controls. Patients were considered to have AIT if they were positive for at least one of either antibodies against thyroid peroxidase (AbTPO) and/or antibodies against thyroglobulin (AbTg), in addition to exhibiting morphological changes consistent with AIT, as diagnosed by thyroid ultrasound (hypoechogenicity, heterogeneity). Individuals were classified as euthyroid AIT at diagnosis if they had normal serum TSH (TSH < 4 mIU/mL) and normal free T4 concentrations. The correlation analysis of BPA with TSH, free T4, free T3, AbTg, AbTPO were also investigated.

Results: Circulating levels of BPA a was significantly higher in euthyroid AIT compared with controls (P<0.05). In correlation analysis, bisphenol a was positively correlated with anti TPO (r=−0.355, P<0.05).

Conclusion: The present study demonstrated for the first time that circulating bisphenol a levels are increased in euthyroid AIT. This result draws attention to the circulating levels of bisphenol a in euthyroid AIT and and may shed light on further researches at this topic.