Sudden sex hormone withdrawal and the effects on body composition in late pubertal adolescents with gender dysphoria.

Background Sex hormones initiate profound physical and physiological changes during the pubertal process, but to what extent are they responsible for continuing the body composition changes of late adolescence and what happens to body composition on sudden sex hormone withdrawal? Methods Thirty-six healthy, phenotypically and chromosomally normal late and post-pubertal individuals aged 15-17 years with gender dysphoria (transgirls - birth-registered males identifying as female n = 11; and transboys - birth-registered females identifying as male n = 25) underwent Tanita body composition analysis at 0, 6 and 12 months during reproductive hormone suppression with Triptorelin as part of the standard therapeutic protocol. Results and conclusions In the transgirl cohort, paired t-test analysis demonstrated a significant decrease in height and lean mass standard deviation scores over the 12-month period, going against an expected trajectory over that time. In contrast, oestrogen suppression appeared not to affect the body composition of transboys; their measurements were not significantly different at baseline and after 12 months of treatment. The withdrawal of sex hormone secretion does not appear to have a significant impact on female post-pubertal body composition, in contrast to that seen at the menopause. This suggests that other factors may preserve normal body balance in adolescents in the absence of sex steroids.