MON-191 Body Composition and Mineral Density in Transgender Patients in Brazil: A Retrospective Cohort

BACKGROUND: Gender identity disorder is defined as a nonconforming biological gender expression, strong and persistent cross-gender identification that is associated with a remarkable uneasiness of living in an incongruent gender. Long term impact on cross-sex hormone therapy (CSHT) in transgender patients is not clear, and many providers are uncomfortable prescribing transgender hormones due to fears over safety. It is expected that drastic hormonal reversal therapy might be associated with a variety of changes , including in lean/fat mass and patients bone health. PATIENTS AND DESIGN METHODS: In a retrospective observational cohort study we evaluated 76 patients using bioimpedance (BI) and dual-energy X-ray absorptiometry (DXA) to assess their body composition and bone densitometry before and during their first 2 years of CSHT. A total of 45 female to male (FtM) group, mean age 25 years (IC 95% 24.26-30.01), transition age 23.27 years ± 5.99, and 31 Male to Female (MtF) group, mean age 40 years (IC 95% 25,42-59.24, transition age 31.30 anos ± 11.17 were evaluated. MEASUREMENTS: Body mass index (BMI), BI and DXA (biological gender comparison). RESULTS: In FtM, basal BMI was 24.05 ± 4.99 and in MtF was 22.67 ± 2.84. Body composition bioimpedance showed in FtM (n 21) 44.09% ± 4.68% of lean mass (LM), 25.95% ± 7.88% of fat mass (FM). In MtF (n 5) we observed 46.82% ± 5% of LM and 21.27% ± 10.87% of FM. Baseline DXA showed in FtM patients spinal BMD (n 16) 1.148 ± 0.148, (Z score -0.06 ± 0.97), femoral neck (FN) 0.977 ± 0.930, (Z score -0.21 ± -0.60), total femur (TF) 0.996 ± 0.113, (Z score 0.12 ± 0.94). MtF patients (n 7) spinal BMD was 1.130 (IC 95% 1.088-1.196), Z score -0,1, FN BMD was 0.924 (IC 95% 0.819-1.059), Z score -0,7 (CI 95% -3.89-4.02) and TF 0.937 (CI 95% 0.729-1.260), Z score -0,6 (CI 95% -3.46-3.73).After 2 years of CSHT treatment, the following changes were found in the FtM population: Weight: -1.04% (CI 95%: -3.59 to 1.52), p 0.41; BMI: -0.25% (CI 95%: -1.23 a 0.73), p 0.61, LM: +0.17% (CI 95%: -0.41 to 0.74), p 0.55 , FM: +0.68% (CI 95%: -1.50 to 2.86), p 0.52 . In MtF population: Weight: -1.98% (CI 95%: -3.7 to -0.25), p 0.02; BMI: -0.51% (CI 95%: -0.99 to -0.18), p 0.04, LM: +0.47% (CI 95%: -0.34 a 1.29), p 0,16, FM: -1.92% (CI 95%: -4.74 to 0.89), p 0.12. CONCLUSIONS: Both groups had similar BMI before starting CSHT. After 2 years of feminizing hormone therapy, it is possible to verify some changes in BMI, mainly by raising the LM in the MtF group. At baseline, trans men had better bone composition, worse LM and elevated FM compared to trans women, as expected. But short term masculinising hormone therapy was not associated with significant changes in these parameters. The impact of these results on patient-important outcomes such as the fracture risk is still uncertain, but in our practice, the hormone therapy experience was safe. We keep following up both groups in a prospective study to evaluated DXA data after 2 and 5 years of CSHT.