Bone Abstracts

Young transsexuals at a minimum age of 12 years are treated with GnRH-analogues (GnRHa) to suspend pubertal development until the addition of hormones of the desired sex is started at a minimum age of 16 years. The effect of this treatment on adult bone mineral density (BMD) is still unknown. We aimed to assess BMD at the age of 22, as this is near its peak in healthy individuals.

In this prospective observational study 19 female to male (FtM) and 16 male to female (MtF) transsexuals were included. In the MtFs mean lumbar and hip BMD were 0.85 (0.66–1.1) and 0.89 (0.68–1.0) g/cm², respectively at start GnRHa (age 15.0 years (12.3–17.9)) and at start estrogen (after 16.5 months (7–45) GnRHa treatment) 0.82 (0.63–0.95) and 0.88 (0.78–0.99) g/cm² respectively. At the age of 22, these were 0.93 (0.75–1.1) and 0.94 (0.74–1.1) g/cm² respectively.

In the FtMs mean lumbar and hip BMD were 0.95 (0.76–1.1) and 0.92 (0.77–1.1) g/cm², respectively, at start GnRHa (age 15.2 years (11.6–18.6)) and at start testosterone (after a GnRHa-treatment duration of 18 months (3–62)) 0.92 (0.76–1.1) and 0.92 (0.75–1.0) respectively. At the age of 22, mean lumbar and hip BMD was 1.0 (0.77–1.1) and 0.94 (0.71–1.1) g/cm² respectively.

BMD remained stable during GnRHa-therapy, deterioration was not observed. Upon hormonal administration, BMD increased until the age of 22. These first data appear to support the safety of the treatment protocol. However, study population was heterogeneous regarding pubertal stage and age at start of treatment and duration of GnRHa-treatment. Further investigation is aimed at continued monitoring of BMD until the age of 30.