Bone Mass Effects of Cross-Sex Hormone Therapy in Transgender People: Updated Systematic Review and Meta-Analysis

Abstract

Context The impact of long-term cross-sex hormone therapy (CSHT) in transgender men and women is still uncertain. Objective To perform a systematic review and meta-analysis and update the evidence regarding the effects of CSHT on bone mineral density (BMD) in transgender men and women. Data Sources Medline, Cochrane Central Register of Controlled Trials, and Embase were searched for studies published until August 2018. Study Selection Of 10,849 studies, 19 were selected for systematic review. All included patients were aged >16 years and received CSHT with BMD assessment by dual-energy X-ray absorptiometry (DXA). Data Extraction Data on BMD, CSHT, and clinical factors affecting bone mass were collected. A National Institutes of Health scale was used to assess the quality of studies. Data Synthesis Nineteen studies were meta-analyzed (487 trans men and 812 trans women). In trans men, mean BMD difference compared with natal women was not significant in any site in either cross-sectional or before-after studies. In trans women, mean BMD difference was not significant compared with natal men at the femoral neck, total femur, and lumbar spine in cross-sectional studies; before-after studies reported a slight but significant increase in lumbar spine BMD after 12 and ≥24 months of treatment. Conclusions Long-term CSHT had a neutral effect on BMD in transgender men. In transgender women, only lumbar spine BMD seemed to be affected after CSHT. This evidence is of low to moderate quality as a result of the observational design of studies, small sample sizes, and variations in hormone therapy protocols.

Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage

“…However, transgender women generally maintain bone mass over the course of at least 24 months of testosterone suppression. There may even be small but significant increases in BMD at the lumbar spine [ 54 , 55 ]. Some retrieved studies present data pertaining to maintained BMD in transgender women after many years of testosterone suppression.…”

Blood Vessels and Vascular Niches in Bone Development and Physiological Remodeling

“…Testosterone treatment conversely led to an increase in cortical bone thickness, but lower bone mineral density (BMD) (Van Caenegem et al, 2012). A meta-analysis found no effect on BMD after testosterone treatment but did report an increase after estrogen treatment (Fighera et al, 2019). Unfortunately, studies into bone vasculature changes after HRT are lacking, although we can speculate that estrogen treatment may lead to increased bone blood flow, thus possibly supporting the observed increase in BMD.…”

IDEA group consensus statement on medical management of adult gender incongruent individuals seeking gender reaffirmation as female

“…This evidence is of low to moderate quality due the observational study design, small sample sizes, and variations in hormone therapy protocols. [ 49 ]…”

“… BMD testing should be done at baseline along with serum calcium and 25(OH) vitamin D If high risk for osteoporotic fracture at baseline: follow up and monitoring every 3 year If low risk for osteoporotic fracture at baseline: follow up at age 60 and then every 3 year. [ 47 49 ] …”

“…If low risk for osteoporotic fracture at baseline: follow up at age 60 and then every 3 year. [ 47 49 ]…”