Background/Aims: More young people with gender dysphoria are undergoing hormonal intervention with GnRHa treatment. The impact on bone density is not known in the very young transgender adolescents, with guidelines mentioning that Bone Mineral Density (BMD) should be monitored without a suggestion on how. This study aimed to investigate whether there were any changes in BMD or Bone Mineral Apparent Density (BMAD) whilst on GnRHa therapy.

Methods: A retrospective analysis of 70 transgender subjects aged 1214 years who were referred to a national centre for the management of gender dysphoria (201116) and had had yearly DEXA scans. A longitudinal analysis (n=31) where subjects had had scans over 3 years and a cross-sectional analysis (n=70) were performed for BMD differences between each scan.

Results: Although there was a decline in age-related Z-scores, there was no significant change in BMAD after one year on GnRHa and no significant changes between DEXA scans for tBMD or BMAD when analysed cross-sectionally or longitudinally over 3 years.

Conclusion: We have shown that there is no actual change in BMAD or tBMD in young transgender adolescents on long term GnRHa therapy, and certainly no true fall as initially suspected. We suggest that yearly DEXA scans may not be necessary. We also suggest that reference ranges may need to be re-defined for this patient cohort.