Abstract
INTRODUCTION: The effects of puberty suppression for more than 2 years before the start of gender-affirming hormones (GAH) on bone mass acquisition and body composition are understudied. MATERIALS AND METHODS: Retrospective study on 46 transgender adolescents (20 trans boys and 26 trans girls) receiving a gonadotropin-releasing hormone analogue (GnRHa) from Tanner stage 2-3, followed by GAH around the age of 16 years. At start of GnRHa and at start of GAH, dual-energy X-ray absorptiometry (DXA) at lumbar spine (LS), femoral neck (FN) and total body (TB), handgrip strength test and fasting blood sampling were performed. Z-scores were calculated using reference values for both cis girls and cis boys. RESULTS: GnRHa were administered for a median of 3.2 years (± 0.69) in trans boys and 2.7 years (± 1.05) in trans girls. Bone mineral apparent density (BMAD)-LS Z-scores decreased significantly in both trans boys and trans girls, while BMAD-FN Z-scores decreased only in trans boys. Fat% and Fat Mass Index Z-scores significantly increased in both groups, while Lean Mass Index Z-scores significantly decreased. Handgrip strength Z-scores for the sex registered at birth (SRAB) remained stable in trans boys while they decreased in trans girls. There was no significant influence of the treatment on either insulin sensitivity or lipid profile. DISCUSSION: GnRHa administration for more than two years during the physiological time of puberty decreases bone mass acquisition, mainly at the lumbar spine and induces a general increase in fat mass. Although lean mass acquisition is undermined in both groups, handgrip strength is affected mainly in trans girls compared with age-matched peers for the SRAB.