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01-10-2009 | Bone health | Article

Low bone mass found in a quarter of male-to-female transsgender patients


Free abstract

MedWire News: Low bone mass is common in male-to-female transgender individuals after gender reassignment surgery , show study findings published in the Journal of Clinical Densitometry.

“Smaller bone size, and a strikingly lower muscle mass compared with men appear to underlie these findings,” say Guy T'Sjoen and co-workers from Ghent University Hospital in Belgium.

To determine the impact of hormone therapy and gender reassignment surgery on bone mass, the team examined 50 male-to-female transgender individuals at least 3 years after beginning anti-androgen and estrogen therapy, and 1 year after orchidectomy and phallectomy plus vaginoplasty.

Overall, patients showed bone mass at the low end of normal distribution, and 26% of the patients had low bone mass, defined as a Z-score of -2 or less, at the lumbar spine, 10% at the femoral neck, and 2% at the total hip.

Furthermore, transgender patients had smaller bone sizes and predominantly lower muscle mass than a comparison group of healthy young men.

However, there was no significant association between bone mass and levels of testosterone, luteinizing hormone, and follicle stimulating hormone, and bone turnover markers were comparable between patients with and without low bone mass.

Finally, there was no significant difference in bone mass between transgender patients using oral and transdermal estrogen therapy.

“Low bone mass is highly prevalent in the described group of male-to-female transgender persons, which appears to be largely determined, in comparison to healthy males, by smaller bone size and a strikingly lower muscle mass,” summarize T'Sjoen et al.

“The underlying mechanism remains to be established,” the researchers say, hypothesizing that androgen deficiency or inadequate estrogen therapy may be causative.

Noting that studies of transgender individuals are small and that hormone protocols differ between centers, the team concludes that the research highlights the need for longitudinal studies on low bone mass in this population.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009

By Lynda Williams

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