Fracture risk assessment in an Italian group of transgender women after gender-confirming surgery

Introduction: Bone health is a critical issue in transgender women (TW) health care. Conflicting results have been reported on bone status after gender-confirming surgery (GCS). No recent data in Italian TW are available. Materials and methods: The aim of this cross-sectional study was to evaluate fracture risk, lumbar spine BMD and 25OH vitamin D (25OHD) levels in a population of TW on estrogen replacement therapy (ERT) after GCS. We retrospectively analyzed a group of 57 TW, aged 45.3 ± 11.3 years, referred to our Gender Dysphoria Clinic, at least 2 years after GCS. Anthropometric parameters, patient compliance to ERT, biochemical and hormonal assessment, lumbar spine BMD and fracture risk were evaluated. Results: Prevalence of low bone mass (Z-score ≤ -2) was 40% according to the natal gender. In this group, 17β-estradiol levels were significantly lower (median 21 pg/ml [25th-75th percentile 10.6–48.5] vs 63 pg/ml [38.5–99.5]; p < 0.001) and a higher prevalence of low compliance to ERT was recorded (83% vs 29%; p < 0.0001) compared to those with higher bone mass. An intermediate–high fracture risk was found in 14% of the sample. A high percentage (93%) of hypovitaminosis D was present. Conclusions: TW on ERT have a high prevalence of low bone mass, significantly associated with low estradiol levels and low compliance to ERT. A high prevalence of hypovitaminosis D was highlighted. Considering that one out of seven TW showed an intermediate-high 10-year fracture risk, such risk assessment may be considered to prevent and manage osteoporosis in this clinical setting.