ESPE Abstracts

The diagnosis of early thelarche is common in Pediatric Endocrinology consultations, with many cases lacking an organic cause. It can either spontaneously resolve, remain stable, or progress to precocious puberty. Early exposure to endocrine-disrupting environmental pollutants (EDs) with estrogenic and/or anti-androgenic effects during pregnancy or childhood may affect the timing of thelarche onset and/or puberty in girls. Further research is needed to better understand the influence of EDs on these developmental milestones.

Objective: To examine potential variations in the levels of exposure to a range of phenolic endocrine-disrupting compounds with estrogenic and/or anti-androgenic activity (such as bisphenols, parabens, and benzophenones) between girls with early thelarche (cases) and healthy girls without this condition (controls)

Methodology: A multicenter, geographical variation-based case-control study was conducted in hospitals across different regions of Spain. The cohort, comprising 110 cases and 97 controls, was recruited between 2018 and 2023, and a preliminary analysis was performed. In urine samples collected from participants, concentrations of three bisphenols (bisphenol A (BPA), S (BPS) and F (BPF)), four parabens (methyl- (MPB), ethyl- (EPB), propyl- (PPB) and butyl-paraben (BPP)) and six UV filters from the benzophenone (BP) family (BP1, BP3, BP6, BP8 and 4OHBP). Associations were examined by unconditional logistic regression models adjusted for hospital, age, BMI z-score, and urinary creatinine.

Results: The girls had a mean age of 6.7 (1.6) years. At least one EDs was detected in 99% of all samples tested. In a greater number of case BPA and BP-1 were detected. The cases presented higher concentrations of BPA, BP1 and 4OHBP. These differences were statistically significant. These results are partial, since this study is in the development phase and the association between these exposures and the risk of early thelarche will be evaluated in a larger sample.

Conclusions: Phenolic endocrine disruptors (EDs) have been identified in nearly all of the analyzed samples, suggesting widespread exposure to EDs among school-age girls. Urinary levels of BPA, a compound known for its estrogenic effects, appear to be elevated in girls with early thelarche. Exposure to BPA may increase the risk of early thelarche. Further studies are needed to assess the influence of exposure to phenols and other EDCs on the risk of early thelarche and precocious puberty.