Bone mineral density and body composition in transgender females prior to cross-sex hormone treatment. Is there any difference with cisgender males?

Abstract

A trans-woman (TW) is a biologically male person with female gender identity. Cisgender
denotes a person whose sense of personal identity and gender corresponds with its birth sex. Cross-sex hormone therapy (CSHT) is one of the options to achieve secondary characteristics of the self-perceived gender. We performed a cross-sectional study. Bone mineral density (BMD), body composition, and muscle strength before starting CSHT were assessed. Twenty-six TW (median age 23.5 years) and cisgender males (median age 25.5 years) were matched for age. TW had less BMD at the lumbar spine (1.040 vs 1.280 g/cm2; p=0.01), total hip (0.970 vs 1.070 g/cm2; p=0.01), and total body (1.080 vs 1.220 g/cm2; p<0.01). They also had less skeletal muscle mass in the arms (5.033 vs 6.212 kg; p<0.01) and legs (16.343 vs 18.404 kg; p=0.02), associated with lower grip strength (p<0.01). It appears that bone and muscle characteristics of TW before starting CSHT differ from cisgender men. Taking these findings into
account, we suggest the inclusion of BMD in the initial evaluation of TW.