Low bone mass is prevalent in male-to-female transsexual persons before the start of cross-sex hormonal therapy and gonadectomy☠☠â˜

ObjectiveCross-sex hormonal therapy and sex reassignment surgery (including gonadectomy) in transsexual persons has an impact on body composition and bone mass and size. However, it is not clear whether baseline differences in bone and body composition between transsexual persons and controls before cross-sex hormonal therapy play a role.DesignA cross-sectional study with 25 male-to-female transsexual persons (transsexual women) before cross-gender sex steroid exposure (median age 30 years) in comparison with 25 age-matched control men and a male reference population of 941 men.Main outcome measuresAreal and volumetric bone parameters using respectively dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT), body composition (DXA), grip strength (hand dynamometer), Baecke physical activity questionnaire, serum testosterone and 25-OH vitamin D.ResultsTranssexual women before cross-sex hormonal therapy presented with less muscle mass (p ≤ 0.001) and strength (p ≤ 0.05) and a higher prevalence of osteoporosis (16%) with a lower aBMD at the hip, femoral neck, total body (all p < 0.001) and lumbar spine (p = 0.064) compared with control men. A thinner radial cortex (p ≤ 0.01) and lower cortical area at the radius and tibia (both p < 0.05) was found in transsexual women vs. control men. Serum testosterone was comparable in all 3 groups, but 25-OH vitamin D was lower in transsexual women (p ≤ 0.001).ConclusionsTranssexual women before the start of hormonal therapy appear to have lower muscle mass and strength and lower bone mass compared with control men. These baseline differences in bone mass might be related to a less active lifestyle.

► 25 male-to-female transsexual persons (transwomen) before cross-sex hormonal therapy ► Bone geometry and body composition was compared with 25 age-matched control men. ► Osteoporosis was more prevalent in transwomen compared with control males (16% vs. 4%). ► Transwomen had less muscle mass and strength vs. controls and lower 25-OH vitamin D. ► Low muscle and bone mass in transwomen might be related to less active lifestyle.