Proandrogenic and Antiandrogenic Progestins in Transgender Youth: Differential Effects on Body Composition and Bone Metabolism

• Published in: The journal of clinical endocrinology and metabolism Vol. 103; no. 6; pp. 2147 - 2156
• Main Authors: Tack, Lloyd J W, Craen, Margarita, Lapauw, Bruno, Goemaere, Stefan, Toye, Kaatje, Kaufman, Jean-Marc, Vandewalle, Sara, T’Sjoen, Guy, Zmierczak, Hans-Georg, Cools, Martine
• Format: Journal Article
• Language: English
• Published: Washington, DC Endocrine Society 01.06.2018; Copyright Oxford University Press; Oxford University Press
• Subjects: Absorptiometry, Photon; Acetic acid; Adolescent; Adolescents; Anthropometry; Body composition; Body Composition - drug effects; Body Composition - physiology; Body fat; Bone composition; Bone density; Bone Density - drug effects; Bone Density - physiology; Bone Development - physiology; Bone mass; Bone turnover; Cancellous bone; Child; Children & youth; Computed tomography; Cyproterone acetate; Cyproterone Acetate - administration & dosage; Cyproterone Acetate - therapeutic use; Dual energy X-ray absorptiometry; Estradiol - blood; Female; Follicle Stimulating Hormone - blood; Grip strength; Hand Strength - physiology; Hormonal effects; Hormone replacement therapy; Humans; Lumbar Vertebrae - diagnostic imaging; Luteinizing Hormone - blood; Lynestrenol - administration & dosage; Lynestrenol - therapeutic use; Male; Metabolism; Progestin; Progestins - blood; Sex Hormone-Binding Globulin - metabolism; Sex hormones; Spine; Spine (lumbar); Testosterone - blood; Transgender Persons; Transsexualism - blood; Transsexualism - diagnostic imaging; Transsexualism - drug therapy; Treatment Outcome
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2017-02316

Abstract Context Progestins can be used to attenuate endogenous hormonal effects in late-pubertal transgender (trans) adolescents (Tanner stage B4/5 and G4/5). Currently, no data are available on the effects of progestins on the development of bone mass or body composition in trans youth. Objective To study prospectively the evolution of body composition and bone mass in late-pubertal trans adolescents using the proandrogenic or antiandrogenic progestins lynestrenol (L) and cyproterone acetate (CA), respectively. Design and Outcome Measurements Forty-four trans boys (Tanner B4/5) and 21 trans girls (Tanner G4/5) were treated with L or CA for 11.6 (4 to 40) and 10.6 (5 to 31) months, respectively. Anthropometry, grip strength, body composition, and bone mass, size, and density were determined by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography before the start of progestin and before addition of cross-sex hormones. Results Using L, lean mass [+3.2 kg (8.6%)] and grip strength [+3 kg (10.6%)] significantly increased, which coincided with a more masculine body shape in trans boys. Trans girls showed loss of lean mass [−2.2 kg (4.7%)], gain of fat mass [+1.5 kg (9.4%)], and decreased grip strength Z scores. CA limited normal bone expansion and impeded pubertal bone mass accrual, mostly at the lumbar spine [Z score: −0.765 to −1.145 (P = 0.002)]. L did not affect physiological bone development. Conclusion Proandrogenic and antiandrogenic progestins induce body composition changes in line with the desired appearance within 1 year of treatment. Bone health, especially at the lumbar spine, is of concern in trans girls, as bone mass accrual is severely affected by androgen suppressive therapy. Proandrogenic and antiandrogenic progestins induce body composition changes toward the desired appearance in trans youth. Bone mass accrual is compromised in trans girls, especially at trabecular bone.