Bone mass in young adulthood following gonadotropin-releasing hormone analog treatment and cross-sex hormone treatment in adolescents with gender dysphoria.

CONTEXT: Sex steroids are important for bone mass accrual. Adolescents with gender dysphoria (GD) treated with gonadotropin-releasing hormone analog (GnRHa) therapy are temporarily sex-steroid deprived until the addition of cross-sex hormones (CSH). The effect of this treatment on bone mineral density (BMD) in later life is not known.

OBJECTIVE: This study aimed to assess BMD development during GnRHa therapy and at age 22 years in young adults with GD who started sex reassignment (SR) during adolescence.

DESIGN AND SETTING: This was a longitudinal observational study at a tertiary referral center.

PATIENTS: Young adults diagnosed with gender identity disorder of adolescence (DSM IV-TR) who started SR in puberty and had undergone gonadectomy between June 1998 and August 2012 were included. In 34 subjects BMD development until the age of 22 years was analyzed.

INTERVENTION: GnRHa monotherapy (median duration in natal boys with GD [transwomen] and natal girls with GD [transmen] 1.3 and 1.5 y, respectively) followed by CSH (median duration in transwomen and transmen, 5.8 and 5.4 y, respectively) with discontinuation of GnRHa after gonadectomy.

MAJOR OUTCOME MEASURES: How BMD develops during SR until the age of 22 years.

RESULTS AND CONCLUSION: Between the start of GnRHa and age 22 years the lumbar areal BMD z score (for natal sex) in transwomen decreased significantly from -0.8 to -1.4 and in transmen there was a trend for decrease from 0.2 to -0.3. This suggests that the BMD was below their pretreatment potential and either attainment of peak bone mass has been delayed or peak bone mass itself is attenuated.