Bone health in gender-diverse individuals: current challenges and future directions

Gender-affirming hormone therapy (GAHT) alters sex-steroid exposure, raising important questions about skeletal health in transgender and gender-diverse populations. Evidence remains fragmented and centred on areal bone mineral density (BMD), with sparse fracture data and little integration of other parameters such as muscle. This narrative review synthesises evidence on skeletal health in transgender individuals, bone density, fracture risk and the muscle-bone unit, bone health screening, and effects of gonadotropin-releasing hormone (GnRH) agonists during adolescence.

We performed a narrative review of clinical studies and guidelines addressing BMD, fractures, puberty suppression, and GAHT in transgender populations, prioritising clinically relevant data.

Multiple cohorts report low pre-GAHT BMD, particularly in individuals assigned-male-at-birth (AMAB), likely reflecting minority stress, low physical activity, suboptimal vitamin D status, and sedentary lifestyles. Adequately dosed GAHT generally maintains or modestly improves BMD, especially in individuals assigned-female-at-birth (AFAB) on testosterone, while modest lumbar spine deficits may persist in some AMAB individuals. Fracture data are limited but reassuring. In adolescents, GnRH-agonists predictably reduce BMD Z-scores during hormonal suppression, with partial recovery after GAHT-initiation. However, implications for peak bone mass remain uncertain. Emerging evidence favours risk-stratified rather than universal dual-energy X-ray absorptiometry (DXA) screening, alongside optimisation of GAHT, nutrition, and physical activity.

Current evidence does not indicate an increased skeletal risk when GAHT is appropriately managed. Pre-existing vulnerabilities appear central to bone health risk stratification, underscoring the need for risk-based care that integrates bone parameters alongside non-skeletal factors, such as muscle.