Endocrine Abstracts

JOINT1591

Introduction: Puberty timing is influenced by exposures to different groups of endocrine disrupting chemicals (EDCs) with different properties. However, our recent systematic review and meta-analysis failed to make firm Conclusions on the impact of EDCs on pubertal development as the majority of the existing studies are cross-sectional using varying statistical approaches.

Aim: The aim of the present study was to investigate the impact of prepubertal concentrations of non-persistent EDCs (i. e. benzophenones, parabens and simple phenolic substances) in relation to pubertal onset in a longitudinal cohort based on data from the Copenhagen Puberty Study.

Methods: In total, 215 healthy children and adolescents (50. 7% girls) were examined every six months for 7 years contributing with a total of 1, 527 examinations, with the median number of examinations per child being 7 (range: 2-14). All children underwent a clinical examination including pubertal staging and had a blood sample drawn for the measurement of reproductive hormone concentrations. Furthermore, the children provided a first morning urine sample at each visit from which urinary concentrations of 9 benzophenones, 7 parabens and 8 phenolic substances were determined using LC-MS/MS.

Results: Several chemicals were detectable in more than 90% of the urine samples, including benzophenone-3 (BP-3), methyl paraben (MeP), and bisphenol A (BPA). In general, chemical concentrations were positively correlated indicating co-exposure from several sources. There was a tendency towards prepubertal urinary BPA concentrations being associated with higher age at pubertal onset in boys (lowest vs. highest BPA tertile: mean age at onset 11. 4 vs. 11. 8 yrs, p-trend= 0. 12) and lower age in girls (10. 9 vs. 10. 1 yrs, p-trend=0. 08). There were no clear associations for prepubertal concentrations of MeP and BP3 in relation to pubertal onset.

Conclusion: All participants were exposed simultaneously to a cocktail of several non-persistent chemicals. There was a strong tendency towards prepubertal BPA levels influencing timing of normal sexual maturation. Detailed statistical analyses of cocktail effects of chemicals on reproductive hormones and timing of puberty are needed and will be further analysed in the project.