Article Text

How does hormone transition in transgender women change body composition, muscle strength and haemoglobin? Systematic review with a focus on the implications for sport participation
  1. Joanna Harper1,
  2. Emma O'Donnell1,
  3. Behzad Sorouri Khorashad2,
  4. Hilary McDermott1,
  5. Gemma L Witcomb1
  1. 1 School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
  2. 2 Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden
  1. Correspondence to Dr Gemma L Witcomb, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK; G.L.Witcomb{at}lboro.ac.uk

Abstract

Objectives We systemically reviewed the literature to assess how long-term testosterone suppressing gender-affirming hormone therapy influenced lean body mass (LBM), muscular area, muscular strength and haemoglobin (Hgb)/haematocrit (HCT).

Design Systematic review.

Data sources Four databases (BioMed Central, PubMed, Scopus and Web of Science) were searched in April 2020 for papers from 1999 to 2020.

Eligibility criteria for selecting studies Eligible studies were those that measured at least one of the variables of interest, included transwomen and were written in English.

Results Twenty-four studies were identified and reviewed. Transwomen experienced significant decreases in all parameters measured, with different time courses noted. After 4 months of hormone therapy, transwomen have Hgb/HCT levels equivalent to those of cisgender women. After 12 months of hormone therapy, significant decreases in measures of strength, LBM and muscle area are observed. The effects of longer duration therapy (36 months) in eliciting further decrements in these measures are unclear due to paucity of data. Notwithstanding, values for strength, LBM and muscle area in transwomen remain above those of cisgender women, even after 36 months of hormone therapy.

Conclusion In transwomen, hormone therapy rapidly reduces Hgb to levels seen in cisgender women. In contrast, hormone therapy decreases strength, LBM and muscle area, yet values remain above that observed in cisgender women, even after 36 months. These findings suggest that strength may be well preserved in transwomen during the first 3 years of hormone therapy.

  • body composition
  • gender issues
  • physiology
  • psychology
  • strength
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Footnotes

  • Contributors GLW devised the study. BSK completed an initial search in 2019 with GLW and HMD. JH completed a second search in 2020 with GLW and EOD. All authors contributed to the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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