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

Lumbar spine BMD significantly increased in AMAB transgender individuals after one year of GAHT.

• Lumbar spine BMD increased from 0.97 ± 0.16 to 1.02 ± 0.14 g/cm², p < 0.001.
• The increase was particularly pronounced in AMAB individuals under 20 years of age.
• Study used dual-energy X-ray absorptiometry (DXA) at baseline and after 1 year of GAHT.
• Study conducted at the University Hospital of Padua between January 2020 and November 2024.

AFAB transgender individuals experienced a modest but significant reduction in femoral neck BMD after one year of GAHT.

• Femoral neck BMD decreased from 0.81 ± 0.12 to 0.79 ± 0.13 g/cm², p < 0.05.
• The reduction was especially notable in the 20–30-year age group.
• This finding suggests site-specific bone loss during testosterone therapy in AFAB individuals.

Age was an independent predictor of BMD change in response to GAHT, with older age associated with reduced skeletal responsiveness.

• Linear regression analysis confirmed age as an independent predictor of BMD change.
• Older age was associated with reduced skeletal responsiveness to GAHT at key femoral sites.
• Younger participants showed greater BMD improvements, while those over 20 exhibited stable or declining values.
• Age-stratified analyses were performed to identify these differential responses.

AMAB individuals often show reduced bone mineral density even before initiating GAHT.

• This pre-existing reduction in BMD in AMAB individuals is noted prior to any hormonal intervention.
• Findings in AFAB individuals before GAHT are described as more variable.
• The authors highlight that adolescence and early adulthood are key periods for peak bone mass accrual.

The study enrolled 269 adults including 162 transgender individuals and 107 cisgender controls in a prospective observational design.

• Study was conducted at the University Hospital of Padua from January 2020 to November 2024.
• Participants were compared to age-matched cisgender controls.
• DXA was performed at baseline and after one year of GAHT.
• The study design was prospective and observational.