Endocrine Abstracts

JOINT1412

International guidelines recommend puberty blocking with GnRH analogs followed by Estradiol treatment (E2) for trans* girls who request medical therapy. There are still uncertainties about possible side effects, is recommended to consider fertility preservation before starting medication, and to periodically assess their bone mineral density (BMD). Besides genetic and hormonal factors, environmental influences on bone mass are crucial, particularly diet, calcium intake, weight, vitamin D levels and sports activity.

Objective: To study the impact of dual therapy on trans* girls in relation to inhibin B levels and BMD. To find out the proportion of minors participate in sports and its potential influence on bone mass acquisition.

Subjects and methodology: Retrospective study of 19 minors who started Triptorelin at an average age of 13.1±1.6 years (65% Tanner III-IV) and E2 at 14.9±1.08. Included variables: inhibin B, weight (SDS for age and gender identity), BMD in g/cm² and in SDS for gender identity and vitamin D levels. Scheduled sports activity data were collected (minimum of 2 hours/week). Variables before and during treatment were studied: Triptorelin (medium dose of 60 µg/k/28 days, started 29.1±6 months prior) and transdermal E2 patches (75 mg/week received for 22.6±9.5 months). SPSS V25 was used for statistical analysis. Non-parametric Wilcoxon test for related samples and Chi-Square for proportions.

Results: Initial data: Inhibin B 204±49 pg/ml, Weight-SDS 0.07±1.6, BMD L1L4 0.89±0.16 g/cm² (SDS –1.1±0.89), total body BMD 0.9±0.11 g/cm² (SDS -0.23±1.1) and vitamin D 21.9±8.5 ng/ml. 23% (5/19) practice sports and 16% (3/19) visited the fertility clinic to request preservation. Inhibin B levels decreased with therapy. In a subgroup of 6 minors who had been on E2 treatment for 36 months, the decrease was even greater (196±47 vs 87±9.5 26). The weight-SDS increased slightly throughout the treatment. During the 2.5 years of combined therapy, BMD increased, the BMD-SDS values for gender in the lumbar spine showed no changes, and in the body, they decreased. Most of the minors did not engage in scheduled sports, and we could not associate this practice with the other variables studied.

Conclusions: Over the first 2.5 years of treatment with Triptorelin and Estradiol in trans* girls, there is a progressive decrease in Inhibin B levels that may compromise their fertility; however, only a minority seeks to preserve it. Most of them do not participate in sports and have low levels of vitamin D, factors that may negatively impact their bone health.