ESPE Abstracts

Objective: Urine phthalic acid esters (PAEs) are one of estrogen-mimetic EDCs. Many studies have suggested that urinary phthalic acid esters (PAEs) are closely related to central precocious puberty (CPP) and isolated premature thelarche (IPT), but there is no study between urinary PAEs and the progression of IPT. This study is to explore the influence of PAEs on the progression of IPT to CPP or early puberty (EP).

Methods: Patients with IPT (74) admitted to the Department of Endocrinology of Shenzhen Children’s Hospital from December 2018 to August 2019, who had been asked to be followed up regularly for one year. The girls were followed clinically every 3 months. During the follow-up period, girls was divided into transformed group and untransformed group. In order to identify independent risk factors affecting significantly the progression of IPT to CPP/EP, we performed a binary logistic regression analysis (forward LR stepwise method) with the progression of IPT to CPP/EP as the dependent variable. The independent variables were those shown to be significant (P< 0.05) in the comparison between two groups (breast Tanner stage, mean ovarian volume, the sun of secondary oxidized Di-(2-ethylhexyl) phthalate(DEHP) metabolites(Σ4DEHP, Σ4DEHP=MEHHP+MEOHP+MECPP+MCMHP)), and other factors that may be clinically correlated (basic LH, IGF-1 SDS, uterine diameter).

Result: IPT girls were successfully followed up in 61 cases, 39 cases in the untransformed group and 22 cases in the transformed group. The transformed group had significantly higher ovarian volume and breast Tanner stage than that in the untransformed group (all P<0.01). The transformed group had significantly higher secondary oxidized DEHP metabolites (MECPP, MEHHP, MEOHP, MCMHP) than that in the untransformed group (all P<0.01). There were no significant difference in other PAEs between the two groups (P>0.05).Among the 61 IPT girls，breast Tanner stage (OR=3.75(1.08-13.01)), Σ4DEHP (OR=3.12(1.33-7.27)) were independent risk factors for the progression of IPT.

Conclusions: Exposure to low level of DEHP for a long time. IPT girls may progress to CPP/EP more possibly. The higher breast Tanner stage is, the more possibly IPT was progressed to CPP/EP.