Human Exposures to Bisphenol A, Bisphenol F and Chlorinated Bisphenol A Derivatives and Thyroid Function

Abstract

Although the increasing prevalence of thyroid nodular disease (TND) has been partially attributed to the more frequent usage of improved diagnostics, environmental factors, such as exposures to thyroid-disrupting chemicals may contribute to TND and altered thyroid function. We investigated the association between exposures to bisphenol A (BPA), its chlorinated derivatives (ClxBPA), and bisphenol F (BPF) with TND and thyroid measures in adult women. A case-control study in Cyprus and Romania (n = 212) was conducted, where cases were those with thyroid nodules (diameter >3mm), and controls without nodules. Serum TSH and free thyroxine and urinary levels of BPA, BPF and ClxBPA were measured using immunoassays and tandem mass spectrometry, respectively. The association between exposures to BPA compounds and TND, adjusting for age, BMI, thyroid hormones and urinary iodine was assessed using logistic regression. Linear regression was used to explore associations between urinary BPA, BPF and ClxBPA and serum thyroid hormones. With the exception of a chlorinated BPA compound (30%), the rest of bisphenols were quantified in 100% of urine samples. A positive and significant (p<0.05) association was observed between urinary BPA and serum TSH that remained after adjusting for urinary creatinine, age, BMI, study site and disease status; there was no significant association between BPF or ClxBPA with TSH. None of the BPA compounds were associated with higher odds of TND. Our study found associations of urinary BPA with TSH but not with BPF or ClxBPA. A larger study would be justified.

Thyroid Disrupting Chemicals

“…In the cohort of adult women evaluated, although urinary BPA concentrations and serum TSH values resulted significantly associated no relationship was found with the prevalence of thyroid nodular disease [31].…”

“…[30] Evaluated the association between thyroid nodular disease and BP-A and -F In the cohort of adult women evaluated, urinary concentration of BPA and serum TSH value were significantly positively associated, but no association was found with the nodular disease [31] Abbreviations: PCBs: Polychlorinated Biphenyls; TT3: total triiodothyronine; TT4: total thyroxin; T4: thyroxin; T4S: thyroxin sulfate: T3: triiodothyronine; rT3: reverse triiodothyronine; TSH: thyroid stimulating hormone; TBG: thyroxine-binding globulin; FT4: free thyroxin; OH-PCB: hydroxylated -Polychlorinated Biphenyls; FT3: free triiodothyronine; TH: thyroid hormones; PBDE: Polybrominated Diphenyl Ethers; NIS: sodium-iodine symporter; BP-A: Bisphenol-A.…”

Thyroid function disruptors: from nature to chemicals

“…Other studies, with different population segments, such as Chinese adults, workers with occupational BPA exposure, men from a fertility clinic, and women with polycystic ovary syndrome all showed similar thyroid profiles, with increased TH levels and/or reduced TSH levels linked to BPA exposure (Meeker et al 2010, Wang et al 2012, Vahedi et al 2016. By contrast, other studies showed positive correlations between urinary BPA and TSH levels (Geens et al 2015, Andrianou et al 2016. There is no consensus in the literature regarding phthalate exposure in male populations, with studies showing an inverse association between MEHP and free T4 and T3 levels (Geens et al 2015, Andrianou et al 2016Meeker et al 2007 and another showing no disruption of TH levels in young males exposed to MEP and MBP (Janjua et al 2007).…”

New EU criteria for endocrine disrupters

“…A South Korean cross-sectional study in adults (M, n=2638; F, n=3365; adults age >19 years) reported a negative correlation between u-BPA and serum TSH levels, but not with serum levels of total T4 or T3 25 [86]. In contrast, a smaller case-control study of thyroid nodular disease in women from Cyprus and Romania (n=212; age 47 and 52 years, respectively) found a positive relation between u-BPA and serum TSH levels by multivariate analyses 26 [87]. The authors reported that plastic bottled water and personal care products usage were significant predictors of spot u-BPA levels.…”