Summary

This review was one of the evidence reviews behind the Endocrine Society's 2017 guideline on treating gender dysphoria (distress about one's sex). The Mayo Clinic team combined 13 studies (639 people, mostly adults) that measured bone density before and after cross-sex hormones. Testosterone in females made no measurable difference to spine or hip bone density over one to two years. Estrogen in males slightly raised spine bone density. Only one study looked at broken bones (none in a year), and only one looked at teenagers given puberty blockers (drugs that pause puberty) and then hormones. That study found males had lower spine bone density at age 22 than before treatment. The authors said the effect on the risk of broken bones is uncertain. The review is reassuring about short-term bone density in adults, but cannot show long-term safety, fracture risk, or safety for teenagers.

Key findings

• Analiza a combinat 13 studii care cuprindeau 639 de persoane: 392 născute de sex masculin și 247 de sex feminin.
• La persoanele de sex feminin care luau testosteron, densitatea osoasă a coloanei inferioare și a șoldului nu s-a schimbat măsurabil după unul sau doi ani.
• La persoanele de sex masculin care luau estrogen, densitatea osoasă a coloanei inferioare a crescut ușor după un an și puțin mai mult după doi ani.
• Doar un studiu, pe 53 de persoane de sex masculin și 53 de sex feminin, a analizat fracturile și nu a găsit niciuna în 12 luni.
• Doar un studiu a acoperit adolescenți cărora li s-au dat blocante ale pubertății și apoi hormoni, iar el a constatat că persoanele de sex masculin aveau o densitate osoasă a coloanei mai mică la 22 de ani decât înainte de tratament.
• Autorii au spus că majoritatea dovezilor proveneau din studii cu un risc moderat de a induce în eroare și că efectul asupra riscului de fracturi este incert.
• Analiza a fost făcută pentru Endocrine Society, folosind un plan elaborat cu experții săi, pentru a susține ghidul său din 2017.

Abstract

BACKGROUND: The impact of sex steroids on bone health in transgender individuals is unclear.

METHODS: A comprehensive search of several databases to 7 April 2015 was conducted for studies evaluating bone health in transgender individuals receiving sex steroids. Pairs of reviewers selected and appraised studies. A random effects model was used to pool weighted mean differences and 95% confidence intervals (CIs).

RESULTS: Thirteen studies evaluating 639 transgender individuals were identified [392 male-to-female (MTF), 247 female-to-male (FTM)]. In FTM individuals and compared with baseline values before initiation of masculinizing hormone therapy, there was no statistically significant difference in the lumbar spine, femoral neck, or total hip bone mineral density (BMD) when assessed at 12 and 24 months. In MTF individuals and compared with baseline values before initiation of feminizing hormone therapy, there was a statistically significant increase in lumbar spine BMD at 12 months (0.04 g/cm2; 95% CI, 0.03 to 0.06 g/cm2) and 24 months (0.06 g/cm2; 95% CI, 0.04 to 0.08 g/cm2). Fracture rates were evaluated in a single cohort of 53 MTF and 53 FTM individuals, with no events at 12 months. The body of evidence is derived mostly from observational studies at moderate risk of bias.

CONCLUSION: In FTM individuals, masculinizing hormone therapy was not associated with significant changes in BMD, whereas in MTF individuals feminizing hormone therapy was associated with an increase in BMD at the lumbar spine. The impact of these BMD changes on patient-important outcomes such as fracture risk is uncertain.

Conclusion

In FTM individuals, masculinizing hormone therapy was not associated with significant changes in BMD, whereas in MTF individuals feminizing hormone therapy was associated with an increase in BMD at the lumbar spine. The impact of these BMD changes on patient-important outcomes such as fracture risk is uncertain.