Changes in regional body fat, lean body mass and body shape in trans persons using cross-sex hormonal therapy : results from a multicenter prospective study

Objective: Cross-sex hormonal therapy (CHT) in trans persons affects their total body fat and total lean body mass. However, it is unknown how separate body regions are affected and whether these changes alter body shape. Therefore, the aim of this study was to determine the effects on body fat and lean body mass in separate body regions and on body shape after one year of CHT. Design and methods: In a multicenter prospective study at university hospitals, 179 male-to-female gender dysphoric persons, referred to as transwomen, and 162 female-to-male gender dysphoric persons, referred to as transmen, were included. All underwent whole-body dual-energy X-ray absorptiometry and anthropometric measurements before and after one year of CHT. Results: In transwomen, increases in body fat ranged from +18% (95% CI: 13%; 23%) in the android region to +42% (95% CI: 37%; 46%) in the leg region and +34% (95% CI: 29%; 38%) in the gynoid region. In transmen, changes in body fat ranged from -16% (95% CI: -19;-14%) in the leg region and -14% in the gynoid region (95% CI: -16%;-12) to no change in the android region (+1%, 95% CI: -3%; 5%). Waist-to-hip ratio (WHR) decreased in transwomen (-0.03, 95% CI: -0.04;-0.02) mainly due to an increase in hip circumference (+3.2 cm, 95% CI: 2.3; 4.0). Transmen have a decrease in hip circumference (-1.9 cm, 95% CI: -3.1;-0.7) resulting in an increase in WHR (+0.01, 95% CI: 0.00;0.02). Conclusions: CHT causes a more feminine body fat distribution and a lower WHR in transwomen and a more masculine body fat distribution with a lower hip circumference in transmen

Prospective evaluation of hematocrit in gender-affirming hormone treatment : results from European Network for the Investigation of Gender Incongruence

In trans persons on gender-affirming hormonal treatment, a decrease (in trans women) or increase (in trans men) in hematocrit is often observed. Reference ranges for evaluation of hematocrit levels in trans persons have not been established. This prospective cohort study is part of the European Network for the Investigation of Gender Incongruence (ENIGI). At the Ghent and Amsterdam sites, we included 625 hormone-naive trans persons. Gender-affirming hormonal treatment was initiated at the first visit. In trans men, serum hematocrit (Hct) levels increased during the first year (+4.9 Hct %, 95% CI 3.82-5.25), with the most pronounced increase during the first 3months (+2.7 Hct %, 95% CI 1.94-3.29). Trans men receiving testosterone esters had a larger increase in serum hematocrit levels compared to trans men receiving testosterone undecanoate ( 0.8 Hct %). Of 192 trans men, 22 (11.5%) developed serum hematocrit levels 50.0%. Trans men on testosterone undecanoate were less likely to develop hematocrit levels 50% or 52%, compared to trans men on testosterone esters, and were less likely to develop hematocrit levels 50%, compared to trans men on testosterone gel. In trans women, serum hematocrit had dropped by 4.1 Hct % (95% CI 3.50-4.37) after 3months, after which only small decreases were observed. In conclusion, serum hematocrit levels can be found in the reference range of the perceived gender as from 3months after the initiation of gender-affirming hormonal treatment