Bone Health · Bone Mineral Density

Age-dependent bone mineral density responses to gender-affirming hormone therapy in transgender individuals: a one-year prospective study

Ceolin C, Dall'Agnol M, Termini G, Papa MV, Casali G, Bertocco A, Scala A, Giannini S, Ferlin A, Sergi G, Garolla A, De Rui M, GIIG group

Published August 4, 2025 Journal of endocrinological investigation
DOI 10.1007/s40618-025-02675-5 PMID 40760393 PMC PMC12640344

Abstract

Purpose

Evidence on the skeletal effects of gender-affirming hormone therapy (GAHT) in transgender individuals remains limited, especially across age groups. Individuals assigned male at birth (AMAB) often show reduced bone mineral density (BMD) even before GAHT, whereas findings in those assigned female at birth (AFAB) are more variable. Given the key role of adolescence and early adulthood in peak bone mass, timely skeletal assessment is essential. This study compared BMD before and after one year (1-y) of GAHT to age-matched cisgender controls.

Methods

Prospective observational study involving 269 adults (162 transgender and 107 cisgender controls) conducted at the University Hospital of Padua (January 2020-November 2024). Dual-energy X-ray absorptiometry (DXA) was performed at baseline and after 1-y of GAHT.

Results

After 1-y of GAHT, in AMAB individuals, lumbar spine BMD significantly increased (from 0.97 ± 0.16 to 1.02 ± 0.14 g/cm², p < 0.001), particularly in those under 20 years. AFAB individuals experienced a modest but significant reduction in femoral neck BMD (from 0.81 ± 0.12 to 0.79 ± 0.13, p < 0.05), especially in the 20–30-year age group. Age-stratified analyses revealed that younger participants showed greater BMD improvements, while those over 20 exhibited stable or declining values. Linear regression confirmed age as an independent predictor of BMD change, with older age associated with reduced skeletal responsiveness to GAHT at key femoral sites.

Conclusions

GAHT has variable effects on bone health, influenced by age and sex assigned at birth. Early initiation may favor bone accrual, especially in AMAB individuals, while AFAB individuals may require closer monitoring for site-specific bone loss during testosterone therapy.

Topics

By this author

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Bone Health › Bone Mineral Density › Peak Bone Mass · Therapeutics › Hormonal Agents › Estrogen Preparations
Chiara Ceolin, Martina Dall'Agnol, Giulia Termini, Giulia Casali, Anna Bertocco, Alberto Scala, Sandro Giannini, Giuseppe Sergi, Marina De Rui
C Ceolin, M Dall'Agnol, G Termini, G Casali, A Bertocco, A Scala, S Giannini, G Sergi, M Rui
PMID 40760393 40760393 DOI 10.1007/s40618-025-02675-5 10.1007/s40618-025-02675-5 Ceolin et al. 2025, Ceolin 2025