Bone density and bone marrow composition in transgender girls prior to pubertal blockade: A case series

To determine bone mineral density (BMD) of transgender girls before pubertal blockade, and correlate with lifestyle and clinical variables. Six transfemale peri-pubertal girls had knee magnetic resonance imaging (MRI) with T1-weighted images and single-voxel proton magnetic resonance spectroscopy (MRS). BMD measurements were obtained via dual-energy X-ray absorptiometry. Questionnaires about physical activity, diet, and the Eating Attitudes Test (EAT-26) were completed. The T2 relaxation rate of water (R2 = 1/T2 in s -1) was correlated with scores on surveys. Three participants (50 %) had a low bone mineral density for age based on total body less head Z-score less than −2; two participants (33 %) had a low BMD for age at lumbar spine. All had EAT-26 scores below threshold for clinical concern. All participants self-reported regular exercise. Bone marrow MR variables (T1, fat fraction, unsaturation index and R2 of water) were not correlated with DXA measures. Participants had low BMD on beginning pubertal blockade. Clinicians should consider monitoring BMD among youth AMAB, a group at potential risk for poor bone health.