Body Composition of Transgender Women After Long-Term Hormone Therapy - a Cross-Sectional Study

Introduction: Few studies of transgender women (TW) body composition (BC) in long-term gender-affirming hormone therapy (GAHT) have been reported. Objective: To evaluate BC parameters of TW in long-term GAHT. Methods: A cross-sectional study was carried out with 8 TW (average age of 34.0 yo ±4.8), 8 cisgender men (CM) and 8 cisgender women (CW) matched to age and body mass index (BMI). All TW were non-gonadectomized subjects and were in estrogen [(E); transdermal estradiol (n=2), oral estradiol (n=3) and conjugated estrogen (n=3)], plus cyproterone acetate (CA) (n=8) therapy in an average time of 15.6 ±8.7 years of treatment. Total testosterone (ng/dL) levels of TW, CW and CM were 83,5 (range 12,0-637,0), 20,5 (range 12,0-41,0) and 480,5 (range 264,0-843,0) at the time of the study, respectively. BC was assessed by InBody 720. Percentage of fat mass (%FM), skeletal muscle mass (SMM) were evaluated. Baumgartner Index was calculated. Results: Regards %FM, that of TW was lower than CW (29,59 ±7,56 vs 32,9 ±3,99; p=0,5394) and higher than CM (23,58 ± 6,44; p=0.1512). SMM of TW was 33.6% higher than that of CW (p<0.001) and 14,7% lower than that of CM (p=0,014). Baumgartner Index of CM group was 17.7% higher than TW group (p=0,001), which presented rates 20.3% higher than the CW (0,002). Discussion: BC changes in the first two years of GAHT in TW were consistent with loss of lean mass and gained fat mass associated with an increase of body weight. This profile was identified in adults and youth transgender after short-term hormone therapy. Conclusion: Our data shown a similar profile of short-term treatment, with a body composition intermediate between BMI-matched cisgender males and females. However, unlike young TW undergoing short-term GAHT, the parameters of BC in the TW using estrogens plus cyproterone acetate in the long term did not present %FM statistically different from CW and CM, in contrast to the lean mass that maintained significant differences in the long term.