Bone health and body composition in transgender adults before gender-affirming hormonal therapy: data from the COMET study

Ceolin C; Scala A; Dall'Agnol M; Ziliotto C; Delbarba A; Facondo P; Citron A; Vescovi B; Pasqualini S; Giannini S; Camozzi V; Cappelli C; Bertocco A; De Rui M; Coin A; Sergi G; Ferlin A; Garolla A; Gender Incongruence Interdisciplinary Group (GIIG)

doi:10.1007/s40618-023-02156-7

Bone Health · Bone Mineral Density

Bone health and body composition in transgender adults before gender-affirming hormonal therapy: data from the COMET study

Ceolin C, Scala A, Dall'Agnol M, Ziliotto C, Delbarba A, Facondo P, Citron A, Vescovi B, Pasqualini S, Giannini S, Camozzi V, Cappelli C, Bertocco A, De Rui M, Coin A, Sergi G, Ferlin A, Garolla A, Gender Incongruence Interdisciplinary Group (GIIG)

Published February 2024 Journal of endocrinological investigation

DOI 10.1007/s40618-023-02156-7 PMID 37450195 PMC PMC10859333

RRM Academy Synopsis

Transgender adults had lower bone density before hormone therapy

Transgender adults had lower bone density than cisgender adults before hormone therapy, a retrospective study of 271 adults in Italy found. About 14 out of 100 transgender and 6 out of 100 cisgender adults had a z-score below -2. Adults assigned male at birth showed the clearest gap, with lower z-scores at all three sites measured and less lean mass.

Key Findings

A bone density z-score below -2 occurred in 14.3% of 125 transgender adults and 6.2% of 146 cisgender controls (p = 0.04).
Adults assigned male at birth (AMAB) had lower z-scores than cisgender men at all three sites measured; lumbar spine averaged -0.99 ± 1.26 against -0.08 ± 1.22 (p < 0.001).
Adults assigned female at birth (AFAB) had lower bone mineral density at the femur than cisgender women (p < 0.001), with no significant difference in z-scores.
In the body composition subset, AFAB participants had more total fat mass than cisgender women (21.24 ± 10.29 vs 14.90 ± 5.53 kg, p < 0.001).
AMAB participants had less total lean mass (53.94 ± 7.74 vs 58.38 ± 6.91 kg, p < 0.05) and weaker handgrip (35.46 ± 9.98 vs 45.32 ± 11.66 kgf, p < 0.01).

Interpretation

COMET is a retrospective study at two Italian hospitals, so links between body composition and bone density are associations. All measurements came before hormone therapy. Participants were 20 to 50 years old. Body composition results cover 55 transgender and 46 cisgender adults. The authors note the small sample and missing data on bone turnover and diet. In this small, young sample, smoking habit and vitamin D level had no significant correlation with bone density. The authors hypothesize that less physical activity and, in AMAB participants, lower lean mass could partly explain the bone differences. They also hypothesize that fat mass may partly compensate for low muscle mass in AMAB participants.

RRM Context

Restorative reproductive medicine treats hormones as one part of whole-body health. Bone, muscle and fat mass belong in that assessment. The authors note that few studies measured bone before hormone therapy began. Baseline data like these give later changes a reference point. They also cite earlier work linking higher estradiol during therapy to better bone density.

Our editorial summary of this paper, not the article's abstract.

Abstract

Purpose

Preliminary data suggested that bone mineral density (BMD) in transgender adults before initiating gender-affirming hormone therapy (GAHT) is lower when compared to cisgender controls. In this study, we analyzed bone metabolism in a sample of transgender adults before GAHT, and its possible correlation with biochemical profile, body composition and lifestyle habits (i.e., tobacco smoke and physical activity).

Methods

Medical data, smoking habits, phospho-calcic and hormonal blood tests and densitometric parameters were collected in a sample of 125 transgender adults, 78 Assigned Females At Birth (AFAB) and 47 Assigned Males At Birth (AMAB) before GAHT initiation and 146 cisgender controls (57 females and 89 males) matched by sex assigned at birth and age. 55 transgender and 46 cisgender controls also underwent a complete body composition evaluation and assessment of physical activity using the International Physical Activity Questionnaire (IPAQ).

Results

14.3% of transgender and 6.2% of cisgender sample, respectively, had z-score values < -2 (p = 0.04). We observed only lower vitamin D values in transgender sample regarding biochemical/hormonal profile. AFAB transgender people had more total fat mass, while AMAB transgender individuals had reduced total lean mass as compared to cisgender people (53.94 ± 7.74 vs 58.38 ± 6.91, p < 0.05). AFAB transgender adults were more likely to be active smokers and tend to spend more time indoor. Fat Mass Index (FMI) was correlated with lumbar and femur BMD both in transgender individuals, while no correlations were found between lean mass parameters and BMD in AMAB transgender people.

Conclusions

Body composition and lifestyle factors could contribute to low BMD in transgender adults before GAHT.

Topics

Bone Health › Bone Mineral Density › Measurement · Lifestyle and Environment › Nutrition and Metabolic Health › Body Weight and Composition

M De Rui

PMID 37450195 37450195 DOI 10.1007/s40618-023-02156-7 10.1007/s40618-023-02156-7 Ceolin et al. 2024, Ceolin 2024

Bone health and body composition in transgender adults before gender-affirming hormonal therapy: data from the COMET study

Transgender adults had lower bone density before hormone therapy

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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