Endocrine Abstracts

Background: In females transitioning to males (FtM) and in males transitioning to females (MtF), exogenous cross-sex steroids are prescribed to favour development of secondary characteristics of desired sex, while endogenous hormone production is inhibited.

Aims and design: To study early impact of cross-sex steroids on body composition, metabolic profile and pro-inflammatory parameters in young transgender persons before and after 12 months of gender-affirming hormonal treatment. Data of non-obese FtM subjects (n = 45; 22.8 ± 4.4 years) and MtF subjects (n = 28; 24.8 ± 5.9 years), followed in the University Hospital of Nancy were retrospectively analysed.

Results: In FtM subjects, testosterone administration led to a significant increase in haemoglobin (13.9 ± 1.6 g/dl vs 15.5 ± 0.9; P < 0.01), and uric acid (41.2 ± 6.2 mg/l vs 53.1 ± 8.7; P < 0.01), associated with a significant decrease in PRL (16.9 ± 4.5 ng/ml vs 9.6 ± 3.2; P < 0.05). Pro-inflammatory indices tended to increase: AST/lymphocyte ratio (8.3 ± 2.6 vs 9.8 ± 3.4; P = 0.08). An android fat distribution was enhanced with an increase in visceral adipose tissue (VAT) (260 ± 217 g vs 368 ± 280; P < 0.01). There was a strong relationship between VAT and the following parameters: BMI, android fat mass, trunk/limb fat mass ratio, android/gynoid fat mass ratio; and between increase in VAT and in haemoglobin levels. In MtF subjects, a significant decrease in haemoglobin (15.4 ± 1 g/dl vs 14.4 ± 0.8; P < 0.05) and in TSH (2.1 ± 1.2 mIU/l vs 1.1 ± 0.6; P < 0.05) level was observed, without meaningful effects on body composition or metabolic profile.

Conclusion: Marked changes in body composition and in metabolic parameters are present in transgender subjects already after the first year of the cross-sex hormonal treatment. Significant increase in in VAT in lean transgender men may confer an increased cardio-metabolic risk in this subpopulation. Early assessment appears necessary to identify the subjects at risk and to individualise treatment regimens. Prospective long-term studies including a large sample size are needed to evaluate effects of early hormonal changes on the risk for cardiovascular diseases in MtF and FtM subjects.