Low Pretreatment Bone Mineral Density in Gender Diverse Youth.

Gender diverse adolescents have low pretreatment bone mineral density (BMD), with variable changes in BMD after initiation of gender-affirming treatment. We aimed to assess factors associated with low BMD in gender diverse youth. Sixty-four patients were included in our analysis (73% assigned male at birth). Subtotal whole-body BMD Z -scores were low in 30% of patients, and total lumbar spine BMD Z -scores low in 14%. There was a positive association with body mass index, and no association with vitamin D level. Male sex assigned at birth was associated with lower pretreatment BMD, with lower average BMD Z -scores compared to previous studies.