Endocrine Abstracts

Transgender persons on gender-affirming hormonal therapy will have experienced a hormonal reversal that will have had direct and also indirect effects on bone, through body composition changes. Recent evidence suggests that transgender women, even before the start of any hormonal intervention, already have a lower bone mass including a higher frequency of osteoporosis, and a smaller bone size vs. cisgender men. During gender-affirming hormonal treatment, bone mass is maintained or increased in transgender women. In transgender men, bone metabolism seemed to increase during short-term testosterone therapy, but no major changes have been found in bone density. On long-term testosterone therapy, larger cortical bone size was observed in transgender men vs. cisgender women. Fracture data as hard endpoint are not available currently. The follow-up of bone health and osteoporosis prevention in transgender persons is important, especially in transgender women. We advise active assessment of osteoporosis risk factors including the (previous) use of hormonal therapy. Based on this risk profile and the intended therapy, bone densitometry may be indicated. Long-term use of antiandrogens or gonadotropin-releasing hormone agonists alone should be monitored as transgender women may have low bone mass, even prior to treatment. Therapy compliance with the gender affirming hormones is of major concern, especially after gonadectomy. Large-scaled, multicenter, and long-term research is needed to determine a well tolerated dosage of gender-affirming hormonal treatment, avoiding side effects. Data on gender non-binary persons and elderly transgender persons are lacking altogether.