Serum Levels of Polybrominated Diphenyl Ethers in Girls with Premature Thelarche

Abstract

Background/Aims: Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants and have shown endocrine disruption properties in experimental studies. The aim of this study was to investigate the association between the exposure to PBDEs and alterations of puberty in girls referred for idiopathic central precocious puberty (ICPP) and premature thelarche (PT). Methods: A case-control study was conducted in 124 girls: 37 girls with ICPP (mean age 7.4 ± 0.9 years), 56 with PT (mean age 5.7 ± 2.1 years) and 31 controls (mean age 5.4 ± 1.9 years). PBDE serum concentrations, hormone levels and anthropometry were assessed. PBDE concentrations were corrected for total serum lipid content. Individual exposure to PBDEs was evaluated through ad hoc questionnaires. Results: PBDE serum concentrations corrected for total lipid content were significantly higher in girls with PT (mean 1.49 ± 0.63 log ng/g) than in controls (mean 1.23 ± 0.54 log ng/g; p < 0.05). PT girls showed higher levels of PBDE than ICPP girls (1.49 ± 0.63 vs. 1.37 ± 0.49 log ng/g), though this was not significant. An analysis of the questionnaires revealed no significant differences in exposure between the three groups. Conclusion: Our findings suggest that higher concentrations of serum PBDEs are associated with PT in girls.

Review of the Literature on Current Changes in the Timing of Pubertal Development and the Incomplete Forms of Early Puberty

“…Some of the possible causes of premature thelarche include increased FSH (but not LH) secretion, excessive dietary intake of estrogens such as phytoestrogens and increased breast sensitivity to circulating estrogens (62), obesity and the role of endocrine-disrupting chemicals (EDCs) such as polybrominated diphenyl ethers (PBDEs), which can cause premature thelarche when it reaches high serum concentrations (63). Crofton et al tried to test whether premature thelarche is associated with increased FSH-driven follicular development; they measured inhibin B (whose role is stimulating estradiol synthesis) and FSH in girls with premature thelarche, central precocious puberty and normal pubertal controls matched for ages and they found that patients with precocious thelarche had inhibin B and FSH levels much higher than their age-matched controls and similar to the levels found in girls with precocious puberty, providing evidence that precocious thelarche is associated with increased follicular development (64).…”

Early-life exposure to endocrine-disrupting chemicals and pubertal development in girls

“…To date, there have been limited studies on pubertal timing, with inconsistent results that depend on the timing of exposure (Table 3) [76,87,90-93]. The limited studies have shown positive associations with premature thelarche [92], earlier pubertal development [90], and age at menarche [91], although associations with later onset of puberty [76,93] or no association [87] have also been reported. Three prospective studies have reported contrasting outcomes in which prenatal PBB/PBDE exposures showed no association [87] or associations with both earlier [90] and later [93] pubertal timing.…”

Current Knowledge on Endocrine Disrupting Chemicals (EDCs) from Animal Biology to Humans, from Pregnancy to Adulthood: Highlights from a National Italian Meeting

“…However, the upper quartile values were comparable to the serum concentrations and was significantly associated with an increased risk of earlier menarche [ 233 ]. In the second study, a case-control study including 37 girls with idiopathic central precocious puberty and 56 with premature thelarche PBDE serum concentrations corrected for total lipid content resulted significantly higher in girls with premature thelarche than in controls and higher than in idiopathic central precocious puberty girls [ 236 ]. The effect of in utero exposure to PBDEs on sexual maturation was evaluated in Michigan girls whose mothers were accidentally exposed through diet to these compounds.…”