Preservation of volumetric bone density and geometry in trans women during cross-sex hormonal therapy: a prospective observational study

• Published in: Osteoporosis international 2015-01, Vol.26 (1), p.35-47
• Main Authors: Van Caenegem, E., Wierckx, K., Taes, Y., Schreiner, T., Vandewalle, S., Toye, K., Kaufman, J.-M., T’Sjoen, G.
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon - methods; Adult; Body Composition; Bone density; Bone Density - drug effects; Bone Density - physiology; Bone Remodeling - drug effects; Case-Control Studies; Endocrine therapy; Endocrinology; Estradiol - pharmacology; Estrogens; Female; Humans; Insulin-Like Growth Factor I - metabolism; Leptin - blood; Male; Medicine; Medicine & Public Health; Middle Aged; Motor Activity - physiology; Muscle Strength - drug effects; Muscle, Skeletal - pathology; Original Article; Orthopedics; Osteoporosis; Prospective Studies; Rheumatology; Sex Reassignment Procedures - methods; Transgender persons; Transsexualism - blood; Transsexualism - physiopathology; Vitamin D - analogs & derivatives; Vitamin D - blood
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-014-2805-3

Summary Although trans women before the start of hormonal therapy have a less bone and muscle mass compared with control men, their bone mass and geometry are preserved during the first 2 years of hormonal therapy, despite of substantial muscle loss, illustrating the major role of estrogen in the male skeleton. Purpose The aim of this study is to examine the evolution of areal and volumetric bone density, geometry, and turnover in trans women undergoing sex steroid changes, during the first 2 years of hormonal therapy. Methods In a prospective observational study, we examined 49 trans women (male-to-female) before and after 1 and 2 years of cross-sex hormonal therapy (CSH) in comparison with 49 age-matched control men measuring grip strength (hand dynamometer), areal bone mineral density (aBMD), and total body fat and lean mass using dual X-ray absorptiometry (DXA), bone geometry and volumetric bone mineral density, regional fat, and muscle area at the forearm and calf using peripheral quantitative computed tomography. Standardized treatment regimens were used with oral estradiol valerate, 4 mg daily (or transdermal 17-β estradiol 100 μg/24 h for patients >45 years old), both combined with oral cyproterone acetate 50 mg daily. Results Prior to CSH, trans women had lower aBMD at all measured sites (all p