Preservation of volumetric bone density and geometry in trans women during cross-sex hormonal therapy: a prospective observational study

High circulating concentrations of estradiol are anabolic for bone mass and strength in an adult male to female transgender mouse model

The effects of gender affirming hormone therapy (GAHT) on bone microarchitecture and fracture risk in adult transgender women is unclear. To investigate the concept that skeletal integrity and strength in trans women may be improved by treatment with a higher dose of GAHT than commonly prescribed, we treated adult male mice with a sustained, high dose of estradiol. Adult male mice at 16 weeks of age were administered ~1.3 mg estradiol by silastic implant, implanted intraperitoneally, for 12 weeks. Controls included vehicle treated intact females and males. High-dose estradiol treatment in males stimulated the endocortical deposition of bone at the femoral mid-diaphysis, increasing cortical thickness and bone area. This led to higher stiffness, maximum force, and the work required to fracture the bone compared to male controls, while post-yield displacement was unaffected. Assessment of the material properties of the bone showed an increase in both elastic modulus and ultimate stress in the estradiol treated males. Treatment of male mice with high dose estradiol was also anabolic for trabecular bone, markedly increasing trabecular bone volume, number and thickness in the distal metaphysis which was accompanied by an increase in the histomorphometric markers of bone remodelling, mineralizing surface/bone surface, bone formation rate and osteoclast number. In conclusion, a high dose of estradiol is anabolic for cortical and trabecular bone in a male to female transgender mouse model, increasing both stiffness and strength. These findings suggest that increasing the current dose of GAHT administered to trans women, while considering other potential adverse effects, may be beneficial to preserving their bone microstructure and strength.

Transgender competition in combat sports: Position statement of the Association of ringside physicians

The Association of Ringside Physicians (ARP) is committed to the concept of fair competition. It advocates for two equally skilled and matched athletes to keep bouts fair, competitive, entertaining, and, most importantly, safe for all combatants. Numerous studies have proven that transgender women may have a competitive athletic advantage against otherwise matched cis-gender women. Likewise, transgender men may suffer a competitive disadvantage against cis-gender men. These differences - both anatomic and physiologic - persist despite normalization of sex hormone levels and create disparities in competitive abilities that are not compatible with the spirit of fair competition. More importantly, allowing transgender athletes to compete against cisgender athletes in combat sports, which already involve significant risk of serious injury, unnecessarily raises the risk of injury due to these differences. Hence the ARP does not support transgender athlete competition against cisgender athletes in combat sports.

Getting old in the desired gender: a systematic review on aging diseases in transgender people

INTRODUCTION

The growing demographic presence of the transgender (TGD) population has sparked an increase in clinical investigations focusing on the impacts of gender-affirming hormone therapy (GAHT) in adults with gender dysphoria. Despite this surge in studies, there remains a significant gap in the literature regarding the health status of older TGD individuals. This review aims to assess prevalent pathological conditions within the TGD population, specifically concentrating on aging-related diseases investigated to date.

METHODS

A systematic search across Embase Ovid, Scopus, PubMed, Cochrane Library, and Web of Science databases was conducted to identify articles reporting on the aging process in TGD individuals. Methodological quality was evaluated using Newcastle-Ottawa Scale (NOS) scores.

RESULTS

Initial database searches yielded 12,688 studies, which were refined to 18 through elimination of duplicates and title/abstract review. Following a comprehensive appraisal, nine studies were included in the systematic review. These articles, published between 2017 and 2023, involved a total of 5403 participants. The evidence indicates a noteworthy percentage of the TGD population being at risk for cardiovascular diseases, experiencing depression or disability, and demonstrating hesitancy toward major recommended screening programs.

CONCLUSIONS

Limited studies on older TGD individuals highlight not only an organic risk of chronic diseases but also a cognitive/psychiatric risk that should not be underestimated. Further research is imperative to deepen our understanding of the pathophysiological mechanisms involved in the health challenges faced by older TGD individuals.

Time Course of Body Composition Changes in Transgender Adolescents During Puberty Suppression and Sex Hormone Treatment

CONTEXT

Transgender adolescents can undergo puberty suppression (PS) and subsequent gender-affirming hormone therapy (GAHT) but little information is available on the expected rate of physical changes.

OBJECTIVE

To investigate the time course of body composition changes during PS and GAHT.

METHODS

In this study, retrospective data of 380 trans boys and 168 trans girls treated with PS prior to GAHT from a gender identity clinic were included. Total lean and fat mass Z-scores using birth-assigned sex as reference were determined using dual-energy X-ray absorptiometry.

RESULTS

In trans boys, lean mass Z-scores decreased (-0.32, 95% CI -0.41; -0.23) and fat mass Z-scores increased (0.31, 95% CI 0.21; 0.41) in the first year of PS and remained stable thereafter. Lean mass Z-scores increased (0.92, 95% CI 0.81; 1.04) and fat mass Z-scores decreased (-0.43, 95% CI -0.57; -0.29) only during the first year of testosterone,. In trans girls, both lean and fat mass Z-scores gradually changed over 3 years of PS (respectively -1.13, 95% CI -1.29; -0.98 and 1.06, 95% CI 0.90; 1.23). In the first year of GAHT, lean mass Z-scores decreased (-0.19, 95% CI -0.36; -0.03) while fat mass Z-scores remained unchanged after 3 years (-0.02, 95% CI -0.20; 0.16).

CONCLUSION

Compared with peers, trans girls experienced ongoing lean mass decrease and fat mass increase during 3 years of PS while in trans boys smaller changes were observed that stabilized after 1 year. A large increase in lean mass Z-scores occurred only during the first year of testosterone treatment. In trans girls, body composition changed only slightly during GAHT. This information can improve counseling about treatment effects.

Considerations for the care of transgender patients in orthopaedics and sports medicine: a narrative review

Orthopaedic and sports medicine clinicians can improve outcomes for transgender patients by understanding the physiological effects of gender-affirming hormone therapy (GAHT). This narrative review investigated the role of GAHT on bone mineral density, fracture risk, thromboembolic risk, cardiovascular health and ligament/tendon injury in this population. A search from the PubMed database using relevant terms was performed. Studies were included if they were levels 1-3 evidence. Due to the paucity of studies on ligament and tendon injury risk in transgender patients, levels 1-3 evidence on the effects of sex hormones in cisgender patients as well as basic science studies were included for these two topics. This review found that transgender patients on GAHT have an elevated fracture risk, but GAHT has beneficial effects on bone mineral density in transgender women. Transgender women on GAHT also have an increased risk of venous thromboembolism, stroke and myocardial infarction compared with cisgender women. Despite these elevated risks, studies have found it is safe to continue GAHT perioperatively for both transgender women and men undergoing low-risk operations. Orthopaedic and sports medicine clinicians should understand these unique health considerations for equitable patient care.

The association of gender-affirming hormone therapy duration and body mass index on bone mineral density in gender diverse adults

Introduction

Feminizing and masculinizing gender-affirming hormone therapy (fGAHT, mGAHT) results in bone mineral density (BMD) maintenance or improvement over time in transgender and gender diverse (TGD) adults. Mostly European TGD studies have explored GAHT's impact on BMD, but the association of BMI and BMD in TGD adults deserves further study.

Objective

To determine whether GAHT duration or BMI are associated with BMD and Z-scores among TGD young adults.

Methods

Cross-sectional study of nonsmoking TGD adults aged 18-40 years without prior gonadectomy or gonadotropin-releasing hormone agonist (GnRHa) therapy taking GAHT for > 1 year. BMD and Z-scores were collected from dual-energy x-ray absorptiometry. Associations between femoral neck, total hip, and lumbar spine BMDs and Z-scores and the predictors, GAHT duration and BMI, were estimated using linear regression.

Results

Among 15 fGAHT and 15 mGAHT, mean BMIs were 27.6 +/- standard deviation (SD) 6.4 kg/m2 and 25.3 +/- 5.9 kg/m2, respectively. Both groups had mean BMDs and Z-scores within expected male and female reference ranges at all three sites. Higher BMI among mGAHT was associated with higher femoral neck and total hip BMDs (femoral neck: β = 0.019 +/- standard error [SE] 0.007 g/cm2, total hip: β = 0.017 +/- 0.006 g/cm2; both p < 0.05) and Z-scores using male and female references. GAHT duration was not associated with BMDs or Z-scores for either group.

Conclusions

Z-scores in young, nonsmoking TGD adults taking GAHT for > 1 year, without prior gonadectomy or GnRHa, and with mean BMIs in the overweight range, were reassuringly within the expected ranges for age based on male and female references. Higher BMI, but not longer GAHT duration, was associated with higher femoral neck and total hip BMDs and Z-scores among mGAHT. Larger, prospective studies are needed to understand how body composition changes, normal or low BMIs, and gonadectomy affect bone density in TGD adults.

Effects of gender-affirming hormone therapy on body fat: a retrospective case‒control study in Chinese transwomen

BACKGROUND

There is insufficient research on how gender-affirming hormone therapy (GAHT) affects body fat modifications in transwomen from China. It is unclear whether hormone therapy affects the prevalence of obesity and blood lipid levels within this population. The current research aimed to assess how GAHT and treatment duration had an impact on the change in and redistribution of body fat in Chinese transwomen.

METHODS

This study included 40 transwomen who had not received GAHT and 59 who had. Body fat, blood lipid, and blood glucose levels were measured. GAHT is mainly a pharmacologic (estrogen and anti-androgen) treatment. The study also stratified participants based on the duration of GAHT to assess its impact on body fat distribution. The duration of GAHT was within one year, one to two years, two to three years, or more than three years.

RESULTS

After receiving GAHT, total body fat increased by 19.65%, and the percentage of body fat increased by 17.63%. The arm, corrected leg, and leg regions showed significant increases in fat content (+ 24.02%, + 50.69%, and + 41.47%, respectively) and percentage (+ 25.19%, + 34.90%, and + 30.39%, respectively). The total visceral fat content decreased (-37.49%). Based on the diagnostic standards for a body mass index ≥ 28 or total body fat percentage ≥ 25% or 30%, the chance of developing obesity did not change significantly. Blood glucose levels significantly increased (+ 12.31%). Total cholesterol levels (-10.45%) decreased significantly. Fat changes in those who received GAHT for one to two years were significantly different from those who did not receive GAHT.

CONCLUSION

After receiving GAHT, total body fat and regional fat increased in Chinese transwomen, and the body fat distribution changed from masculine to feminine, especially during the first two years. However, neither the increase in total body fat percentage nor the decrease in visceral fat content didn't bring about significant changes in the incidence of obesity, nor did triglycerides or low-density lipoprotein-cholesterol.

Unraveling sex-specific risks of knee osteoarthritis before menopause: Do sex differences start early in life?

OBJECTIVE

Sufficient evidence within the past two decades have shown that osteoarthritis (OA) has a sex-specific component. However, efforts to reveal the biological causes of this disparity have emerged more gradually. In this narrative review, we discuss anatomical differences within the knee, incidence of injuries in youth sports, and metabolic factors that present early in life (childhood and early adulthood) that can contribute to a higher risk of OA in females.

DESIGN

We compiled clinical data from multiple tissues within the knee joint-since OA is a whole joint disorder-aiming to reveal relevant factors behind the sex differences from different perspectives.

RESULTS

The data gathered in this review indicate that sex differences in articular cartilage, meniscus, and anterior cruciate ligament are detected as early as childhood and are not only explained by sex hormones. Aiming to unveil the biological causes of the uneven sex-specific risks for knee OA, we review the current knowledge of sex differences mostly in young, but also including old populations, from the perspective of (i) human anatomy in both healthy and pathological conditions, (ii) physical activity and response to injury, and (iii) metabolic signatures.

CONCLUSIONS

We propose that to close the gap in health disparities, and specifically regarding OA, we should address sex-specific anatomic, biologic, and metabolic factors at early stages in life, as a way to prevent the higher severity and incidence of OA in women later in life.

The impact of gender-affirming hormone therapy on nutrition-relevant biochemical measures

Gender-affirming hormone therapy carries the potential risk for shifts in biochemical markers that may impact cardiometabolic, hematologic, hepatic, and renal health. The critical evaluation of biochemical data is an integral part of a comprehensive nutrition assessment; therefore, nutrition professionals should be aware of shifts that are expected during the course of masculinizing and feminizing hormone therapy. Changes in important biochemical values along with binary sex-specific standards for interpreting laboratory data can pose significant challenges for nutrition professionals working with transgender and gender-diverse patients who receive gender-affirming hormone therapy. Overall, research on the biochemical impact of masculinizing and feminizing hormone therapy is nascent and limited. Methodologies and outcomes measured are heterogenous across studies, introducing complexities that impede researchers from drawing definitive conclusions. In light of these limitations, this narrative review aims to describe the potential implications of masculinizing and feminizing hormone therapy regimens on biochemical measures that may influence nutrition strategies and interventions to promote optimal health.

The International Olympic Committee framework on fairness, inclusion and nondiscrimination on the basis of gender identity and sex variations does not protect fairness for female athletes

The International Olympic Committee (IOC) recently published a framework on fairness, inclusion, and nondiscrimination on the basis of gender identity and sex variations. Although we appreciate the IOC's recognition of the role of sports science and medicine in policy development, we disagree with the assertion that the IOC framework is consistent with existing scientific and medical evidence and question its recommendations for implementation. Testosterone exposure during male development results in physical differences between male and female bodies; this process underpins male athletic advantage in muscle mass, strength and power, and endurance and aerobic capacity. The IOC's "no presumption of advantage" principle disregards this reality. Studies show that transgender women (male-born individuals who identify as women) with suppressed testosterone retain muscle mass, strength, and other physical advantages compared to females; male performance advantage cannot be eliminated with testosterone suppression. The IOC's concept of "meaningful competition" is flawed because fairness of category does not hinge on closely matched performances. The female category ensures fair competition for female athletes by excluding male advantages. Case-by-case testing for transgender women may lead to stigmatization and cannot be robustly managed in practice. We argue that eligibility criteria for female competition must consider male development rather than relying on current testosterone levels. Female athletes should be recognized as the key stakeholders in the consultation and decision-making processes. We urge the IOC to reevaluate the recommendations of their Framework to include a comprehensive understanding of the biological advantages of male development to ensure fairness and safety in female sports.

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

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.

Three cases highlighting possible discrepancies in the interpretation of transgender DXA scores

For diagnosis of osteoporosis, a T-score of ≤-2.5 is recommended for all transgender and gender-diverse patients aged 50 years or older, regardless of hormonal status. This case series presents 3 transgender individuals younger than 50 years undergoing gender-affirming hormone therapy (GAHT) who had DXA scores suggestive of osteoporosis. We highlight possible discrepancies in DXA scan interpretations, especially in forearm bone mineral density measurements. We present the baseline (prior to beginning GAHT), 6-month, and 1-year follow-up DXA data along with pertinent labs to include 25-OH vitamin D, calcium, and alkaline phosphatase, for 2 transgender males (assigned female at birth) and 1 transgender female (assigned male at birth) undergoing GAHT who had low Z-scores and T-scores suggestive of osteoporosis. Multiple studies have analyzed the BMD data of individuals taking GAHT over time, which identify possible causes for low baseline Z-scores for transgender females, but less so for transgender males. Other than positional statements, guidelines remain unclear regarding diagnostic approaches to osteoporosis and low Z-scores in transgender individuals who are premenopausal or under 50 years of age. This case series addresses discrepancies in interpretation that may be encountered by clinicians with baseline and follow-up DXAs, especially involving the forearm, during the course of GAHT. This highlights the importance of establishing clearer guidelines for the diagnosis and treatment of osteoporosis and low BMD for chronological age in the transgender population.

The Impact of Gender-Affirming Hormone Therapy on Physical Performance

CONTEXT

The inclusion of transgender people in elite sport has been a topic of debate. This narrative review examines the impact of gender-affirming hormone therapy (GAHT) on physical performance, muscle strength, and markers of endurance.

EVIDENCE ACQUISITION

MEDLINE and Embase were searched using terms to define the population (transgender), intervention (GAHT), and physical performance outcomes.

EVIDENCE SYNTHESIS

Existing literature comprises cross-sectional or small uncontrolled longitudinal studies of short duration. In nonathletic trans men starting testosterone therapy, within 1 year, muscle mass and strength increased and, by 3 years, physical performance (push-ups, sit-ups, run time) improved to the level of cisgender men. In nonathletic trans women, feminizing hormone therapy increased fat mass by approximately 30% and decreased muscle mass by approximately 5% after 12 months, and steadily declined beyond 3 years. While absolute lean mass remains higher in trans women, relative percentage lean mass and fat mass (and muscle strength corrected for lean mass), hemoglobin, and VO2 peak corrected for weight was no different to cisgender women. After 2 years of GAHT, no advantage was observed for physical performance measured by running time or in trans women. By 4 years, there was no advantage in sit-ups. While push-up performance declined in trans women, a statistical advantage remained relative to cisgender women.

CONCLUSION

Limited evidence suggests that physical performance of nonathletic trans people who have undergone GAHT for at least 2 years approaches that of cisgender controls. Further controlled longitudinal research is needed in trans athletes and nonathletes.

The Utility of Preclinical Models in Understanding the Bone Health of Transgender Individuals Undergoing Gender-Affirming Hormone Therapy

PURPOSE OF REVIEW

To summarise the evidence regarding the effects of gender-affirming hormone therapy (GAHT) on bone health in transgender people, to identify key knowledge gaps and how these gaps can be addressed using preclinical rodent models.

RECENT FINDINGS

Sex hormones play a critical role in bone physiology, yet there is a paucity of research regarding the effects of GAHT on bone microstructure and fracture risk in transgender individuals. The controlled clinical studies required to yield fracture data are unethical to conduct making clinically translatable preclinical research of the utmost importance. Novel genetic and surgical preclinical models have yielded significant mechanistic insight into the roles of sex steroids on skeletal integrity. Preclinical models of GAHT have the potential inform clinical approaches to preserve skeletal integrity and prevent fractures in transgender people undergoing GAHT. This review highlights the key considerations required to ensure the information gained from preclinical models of GAHT are informative.

The Experience of HIV-Positive Transgender Women Engaging in Physical Activity: An Interpretative Phenomenological Analysis

Regular physical activity should benefit HIV-positive transgender women because they are a particularly vulnerable population. However, engaging in physical activity seems particularly difficult among this population. To inform the development of interventions to increase adherence to physical activity, we explored perceptions of physical activity in 10 semi-structured interviews with HIV-positive transgender women. Interviews were subjected to a qualitative approach named interpretative phenomenological analysis (IPA). Inspired by Cooley's theory, we chose to illustrate the results according to a three-level structure, i.e., confronting oneself to oneself with a specific identity, then confronting oneself with others on an interpersonal level, and eventually confronting oneself with society as a normative frame through the specific prism of physical activity, and thus relationship to one's body. The idea of practicing physical activity meant for them: having to face what they tried to be kept hidden, being ostracized by the cis population, and facing social heteronormativity. The fears about health were mostly about HIV and the transitioning process side effects. The psychological issues were mostly about the fear of developing male shaped bodies and worsened by traumatic life stories. External factors were often related to the passing concept and violence caused by stigma and discrimination. The group appeared as a strong motivation factor, facilitating self-acceptance and socialization.

Bone Health in the Transgender Population

» Transgender women are more susceptible to low bone mineral density (BMD) before initiating gender-affirming hormone therapy (GAHT), and while bone density initially improves with GAHT, it gradually declines while still remaining above baseline. Transgender women older than 50 years have a comparable fracture risk as age-matched cisgender women. Transgender men typically have normal or increased BMD before initiating and while receiving GAHT and are not at increased risk of fractures.» Transgender youth who receive puberty-blocking medications experience either no change or a slight decrease in BMD that returns to baseline after initiating GAHT.» It is important to abide by the International Society for Clinical Densitometry guidelines whenever ordering, performing, or reading a BMD scan for a gender-diverse patient.» There are no specific guidelines concerning vitamin D and calcium supplementation or the use of bisphosphonates in the transgender population, so the current recommendation is to abide by the guidelines for cisgender individuals.

Musculoskeletal health considerations for the transgender athlete

BACKGROUND

In addition to the familiar sports-related injuries and conditions experienced by cisgender athletes, transgender athletes may also face unique challenges to maintaining their musculoskeletal health. Encouraging sports medicine professionals to become familiar with accepted nomenclature and terminology related to transgender athletes will enable open communication on the field, in the athletic training facility, and office.

OBJECTIVE

Understanding contemporary medical and surgical gender-affirming treatments and the unique ways in which the musculoskeletal system might be affected by each - such as impairments in bone health, changes in ligamentous function and the potential increased risk for deep venous thromboembolism - is essential for provision of optimal musculoskeletal care to transgender athletes. Knowledge of the existing participation policies for transgender athletes is also key for enabling sports medicine professionals to effectively counsel athletes about the need for specialized protective equipment. Additionally, this knowledge is important for appropriately managing therapeutic use exemptions in the competitive sports setting.

CONCLUSION

This article provides an overview of the current accepted nomenclature, common gender-affirming medical and surgical treatments, unique musculoskeletal health considerations, and participation policies for transgender athletes.

Clinical Concerns on Sex Steroids Variability in Cisgender and Transgender Women Athletes

In the female athletic community, there are several endogenous and exogenous variables that influence the status of the hypothalamus-pituitary-ovarian axis and serum sex steroid hormones concentrations (e. g., 17β-estradiol, progesterone, androgens) and their effects. Moreover, female athletes with different sex chromosome abnormalities exist (e. g., 46XX, 46XY, and mosaicism). Due to the high variability of sex steroid hormones serum concentrations and responsiveness, female athletes may have different intra- and inter-individual biological and functional characteristics, health conditions, and sports-related health risks that can influence sports performance and eligibility. Consequently, biological, functional, and/or sex steroid differences may exist in the same and in between 46XX female athletes (e. g., ovarian rhythms, treated or untreated hypogonadism and hyperandrogenism), between 46XX and 46XY female athletes (e. g., treated or untreated hyperandrogenism/disorders of sexual differentiation), and between transgender women and eugonadal cisgender athletes. From a healthcare perspective, dedicated physicians need awareness, knowledge, and an understanding of sex steroid hormones' variability and related health concerns in female athletes to support physiologically healthy, safe, fair, and inclusive sports participation. In this narrative overview, we focus on the main clinical relationships between hypothalamus-pituitary-ovarian axis function, endogenous sex steroids and health status, health risks, and sports performance in the heterogeneous female athletic community.

Gender-affirming hormonal therapy for transgender and gender-diverse people-A narrative review

As the number of transgender and gender-diverse (TGD) people accessing gender-affirming care increases, the need for healthcare professionals (HCPs) providing gender-affirming hormonal therapy (GAHT) also increases. This chapter provides an overview of the HCPs interested in getting involved in providing GAHT.

Characterising body composition and bone health in transgender individuals receiving gender-affirming hormone therapy

BACKGROUND

Gender-affirming hormone therapy (GAHT) is prescribed to produce secondary sex characteristics aligning external anatomy with gender identity to mitigate gender dysphoria. Transgender women are generally treated with oestrogens and anti-androgens, whereas transgender men are treated with testosterone. The objective of this narrative review was to characterise the influence of GAHT on body composition and bone health in the transgender population to help address weight concerns and chronic disease risk.

METHODS

Studies were extracted from PubMed and Scopus and limited to only those utilising imaging technologies for precise adipose tissue, lean mass, and bone mineral density (BMD) quantification.

RESULTS

Although methodologies differed across the 20 investigations that qualified for inclusion, clear relationships emerged. Specifically, among transgender women, most studies supported associations between oestrogen therapy and decreases in lean mass and increases in both, fat mass and body mass index (BMI). Within transgender men, all studies reported associations between testosterone therapy and increases in lean mass, and although not as consistent, increases in BMI and decreases in fat mass. No consistent changes in BMD noted for either group.

CONCLUSIONS

Additional research is needed to appropriately assess and evaluate the implications of these body composition changes over time (beyond 1 year) in larger, more diverse groups across all BMI categories. Future studies should also seek to evaluate nutrient intake, energy expenditure and other important lifestyle habits to diminish health disparities within this vulnerable population. Policies are needed to help integrate registered dietitians into the routine care of transgender individuals.

Medical considerations in the care of transgender and gender diverse patients with eating disorders

Transgender and gender diverse (TGD) individuals are at increased risk for the development of eating disorders, but very little has been published with regards to the unique aspects of their medical care in eating disorder treatment. Providing gender affirming care is a critical component of culturally competent eating disorder treatment. This includes knowledge of gender affirming medical and surgical interventions and how such interventions may be impacted by eating disordered behaviors, as well as the role of such interventions in eating disorder treatment and recovery. TGD individuals face barriers to care, and one of these can be provider knowledge. By better understanding these needs, clinicians can actively reduce barriers and ensure TGD individuals are provided with appropriate care. This review synthesizes the available literature regarding the medical care of TGD patients and those of patients with eating disorders and highlights areas for further research.

Osteoporosis and Bone Health in Transgender Individuals

This review discusses the changes in bone mass, structure, and metabolism that occur upon gender-affirming hormonal treatment (GAHT) in transgender adults and adolescents, as well as their clinical relevance. In general, available evidence shows that GAHT in transgender adults is not associated with major bone loss. In transgender adolescents, pubertal suppression with gonadotropin-releasing hormone agonist monotherapy impairs bone development, but at least partial recovery is observed after GAHT initiation. Nevertheless, a research gap remains concerning fracture risk and determinants of bone strength other than bone mineral density. Attention for bone health is warranted especially in adult as well as adolescent trans women, given the relatively high prevalence of low bone mass both before the start of treatment and after long-term GAHT in this population. Strategies to optimize bone health include monitoring of treatment compliance and ensuring adequate exposure to administered sex steroids, in addition to general bone health measures such as adequate physical activity, adequate vitamin D and calcium intake, and a healthy lifestyle. When risk factors for osteoporosis exist the threshold to perform DXA should be low, and treatment decisions should be based on the same guidelines as the general population.

Gender-affirming hormone therapy: An updated literature review with an eye on the future

In line with increasing numbers of transgender (trans) and gender nonbinary people requesting hormone treatment, the body of available research is expanding. More clinical research groups are presenting data, and the numbers of participants in these studies are rising. Many previous review papers have focused on all available data, as these were scarce, but a more recent literature review is timely. Hormonal regimens have changed over time, and older data may be less relevant for today's practice. In recent literature, we have found that even though mental health problems are more prevalent in trans people compared to cisgender people, less psychological difficulties occur, and life satisfaction increases with gender-affirming hormone treatment (GAHT) for those who feel this is a necessity. With GAHT, body composition and contours change towards the affirmed sex. Studies in bone health are reassuring, but special attention is needed for adolescent and adult trans women, aiming at adequate dosage of hormonal supplementation and stimulating therapy compliance. Existing epidemiological data suggest that the use of (certain) estrogens in trans women induces an increased risk of myocardial infarction and stroke, the reason that lifestyle management can be an integral part of trans health care. The observed cancer risk in trans people does not exceed the known cancer-risk differences between men and women. Now it is time to integrate the mostly reassuring data, to leave the overly cautious approach behind, to not copy the same research questions repeatedly, and to focus on longer follow-up data with larger cohorts.

The ENIGI (European Network for the Investigation of Gender Incongruence) Study: Overview of Acquired Endocrine Knowledge and Future Perspectives

Literature on the efficacy and safety of gender-affirming hormonal treatment (GAHT) in transgender people is limited. For this reason, in 2010 the European Network for the Investigation of Gender Incongruence (ENIGI) study was born. The aim of this review is to summarize evidence emerging from this prospective multicentric study and to identify future perspectives. GAHT was effective in inducing desired body changes in both trans AMAB and AFAB people (assigned male and female at birth, respectively). Evidence from the ENIGI study confirmed the overall safety of GAHT in the short/mid-term. In trans AMAB people, an increase in prolactin levels was demonstrated, whereas the most common side effects in trans AFAB people were acne development, erythrocytosis, and unfavorable changes in lipid profile. The main future perspectives should include the evaluation of the efficacy and safety of non-standardized hormonal treatment in non-binary trans people. Furthermore, long-term safety data on mortality rates, oncological risk, and cardiovascular, cerebrovascular and thromboembolic events are lacking. With this aim, we decided to extend the observation of the ENIGI study to 10 years in order to study all these aspects in depth and to answer these questions.

Bone health in transgender people: a narrative review

Bone health in transmen and transwomen is an important issue that needs to be evaluated by clinicians. Prior to gender-affirming hormone treatment (GAHT), transwomen have lower bone mineral density (BMD) and a higher prevalence of osteopenia than cismen probably related to external factors, such as hypovitaminosis D and less physical activities. Gonadotropin-releasing hormone (GnRH) analogues in transgender youth may cause bone loss; however, the addition of GAHT restores or at least improves BMD in both transboys and transgirls. The maintenance or increase in BMD shown in short-term longitudinal studies emphasizes that GAHT does not have a negative effect on BMD in adult transwomen and transmen. Gonadectomy is not a risk factor if GAHT is taken correctly. The prevalence of fractures in the transgender population seems to be the same as in the general population but more studies are required on this aspect. To evaluate the risk of osteoporosis, it is mandatory to define the most appropriate reference group not only taking into consideration the medical aspects but also in respect of the selected gender identity of each person.

SPORTS AND PERFORMANCE IN THE TRANSGENDER POPULATION: A SYSTEMATIC REVIEW AND META-ANALYSIS

ABSTRACT Introduction: The debate surrounding the regulations on the participation of transgender individuals in sports is not recent, but it is still ongoing. Some sports organizations are more flexible in this regard, while others are more conservative. Objective: Through a systematic review and meta-analysis, this study summarizes the scientific evidence of the effects of cross-sex hormone therapy on muscle strength, hematocrit, and hemoglobin measurements, parameters that seem to be linked to sports performance. Methods: We conducted electronic searches for manuscripts published before November 20th, 2020. Studies published in three different databases (PubMed, SciELO, and Lilacs) were included, without any time or language restriction, and using keywords such as “transgender”, “gender dysphoria”, “strength”, “hematocrit”, and “hemoglobin”. The PRISMA systematization was used for the elaboration of this review, while a meta-analysis was conducted to mathematically evidence the results. The meta-analysis was performed using the random effect model, to find the pooled estimate effect of cross-sex hormone therapy on the parameters analyzed. Results: The electronic search retrieved 21 articles that were eligible for inclusion. Cross-sex hormone therapy influenced the three parameters analyzed in almost all the studies. Overall, there was a significant increase in muscle strength in female-to-males (FtMs), per muscle group analyzed: +17.7% (95% confidence interval [CI]14.9;20.6). In male-to-females (MtFs) the results of the muscle strength analysis were more controversial, but the pooled estimate effect showed a decrease: −3.6% (95% confidence interval [CI] −6.6; −0.6). Conclusion: Muscle strength, hematocrit, and hemoglobin were altered as a result of cross-sex hormone therapy in both FtMs and MtFs. However, there was a lack of studies comparing the transgender individuals to the population of the same desired gender. Such studies are needed, to better infer rules for the participation of transgender athletes in Olympic sports. Level of Evidence I; Systematic Review and Meta-analysis.

Relationship Between Serum Estradiol Concentrations and Clinical Outcomes in Transgender Individuals Undergoing Feminizing Hormone Therapy: A Narrative Review

Transgender, including gender diverse and nonbinary, individuals are treated with estradiol with or without antiandrogen to align their physical appearance with their gender identity, improve mental health and quality of life. Consensus guidelines give target ranges for serum estradiol concentration based on premenopausal female reference ranges. However, limited studies have evaluated the relationship between serum estradiol concentrations and clinical outcomes in transgender individuals undergoing feminizing hormone therapy. The available evidence has not found that higher serum estradiol concentrations, together with suppressed testosterone, enhance breast development, or produce more feminine changes to body composition. However, ensuring testosterone suppression appears to be an important factor to maximize these physical changes. Higher serum estradiol concentrations have been associated with higher areal bone mineral density. Although the resultant long-term clinical implications are yet to be determined, this could be a consideration for individuals with low bone mass. The precise serum estradiol concentration that results in adequate feminization without increasing the risk of complications (thromboembolic disease, cholelithiasis) remains unknown. Further prospective trials are required.

Development of Hip Bone Geometry During Gender-Affirming Hormone Therapy in Transgender Adolescents Resembles That of the Experienced Gender When Pubertal Suspension Is Started in Early Puberty

Bone geometry can be described in terms of periosteal and endocortical growth and is partly determined by sex steroids. Periosteal and endocortical apposition are thought to be regulated by testosterone and estrogen, respectively. Gender-affirming hormone (GAH) treatment with sex steroids in transgender people might affect bone geometry. However, in adult transgender people, no change in bone geometry during GAH was observed. In this study, we investigated changes in bone geometry among transgender adolescents using a gonadotropin-releasing hormone agonist (GnRHa) and GAH before achieving peak bone mass. Transgender adolescents treated with GnRHa and subsequent GAH before the age of 18 years were eligible for inclusion. Participants were grouped based on their Tanner stage at the start of GnRHa treatment and divided into early, mid, and late puberty groups. Hip structure analysis software calculating subperiosteal width (SPW) and endocortical diameter (ED) was applied to dual-energy X-ray absorptiometry scans performed at the start of GnRHa and GAH treatments, and after ≥2 years of GAH treatment. Mixed-model analyses were performed to study differences over time. Data were visually compared with reference values of the general population. A total of 322 participants were included, of whom 106 were trans women and 216 trans men. In both trans women and trans men, participants resembled the reference curve for SPW and ED of the experienced gender but only when GnRHa was started during early puberty. Those who started during mid and late puberty remained within the reference curve of the gender assigned at birth. A possible explanation might be sought in the phenomenon of programming, which conceptualizes that stimuli during critical windows of development can have major consequences throughout one's life span. Therefore, this study adds insights into sex-specific bone geometry development during puberty of transgender adolescents treated with GnRHa, as well as the general population. © 2021 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

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

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.

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

Males enjoy physical performance advantages over females within competitive sport. The sex-based segregation into male and female sporting categories does not account for transgender persons who experience incongruence between their biological sex and their experienced gender identity. Accordingly, the International Olympic Committee (IOC) determined criteria by which a transgender woman may be eligible to compete in the female category, requiring total serum testosterone levels to be suppressed below 10 nmol/L for at least 12 months prior to and during competition. Whether this regulation removes the male performance advantage has not been scrutinized. Here, we review how differences in biological characteristics between biological males and females affect sporting performance and assess whether evidence exists to support the assumption that testosterone suppression in transgender women removes the male performance advantage and thus delivers fair and safe competition. We report that the performance gap between males and females becomes significant at puberty and often amounts to 10-50% depending on sport. The performance gap is more pronounced in sporting activities relying on muscle mass and explosive strength, particularly in the upper body. Longitudinal studies examining the effects of testosterone suppression on muscle mass and strength in transgender women consistently show very modest changes, where the loss of lean body mass, muscle area and strength typically amounts to approximately 5% after 12 months of treatment. Thus, the muscular advantage enjoyed by transgender women is only minimally reduced when testosterone is suppressed. Sports organizations should consider this evidence when reassessing current policies regarding participation of transgender women in the female category of sport.

A Randomized Double-Blind Placebo-Controlled Pilot Trial on the Effects of Testosterone Undecanoate Plus Dutasteride or Placebo on Muscle Strength, Body Composition, and Metabolic Profile in Transmen

BACKGROUND

While the effects of androgens on muscle are well described in hypogonadal men, literature is still scarce on muscular strength or size variations in transmen; in this population there are no data regarding the relative effect of testosterone (T) and its metabolite dihydrotestosterone on muscle.

AIM

Our primary objective was to compare the effects on muscle strength of 54-week administration of testosterone undecanoate (TU) combined with the 5α-reductase inhibitor dutasteride (DT) or placebo (PL). Secondary outcomes included evaluation of body composition, bone, cutaneous androgenic effects, and metabolic variations.

METHODS

In this randomized, double-blind PL-controlled pilot trial, 16 ovariectomized transmen were randomized to receive TU 1,000 mg IM at week 0, 6, 18, 30, 42 plus a PL pill orally daily (TU + PL, n = 7) or plus DT 5 mg/d (TU + DT, n = 7).

OUTCOMES

At week 0 and 54 the following parameters were evaluated: isokinetic knee extension and flexion peak torque and handgrip strength, body composition, and bone mineral density, biochemical, hematological, and hormonal parameters.

RESULTS

Handgrip and lower limb strength increased significantly in both groups with no differences between the 2 groups. Fat mass decreased and lean mass increased significantly similarly in both groups. Metabolic parameters remained stable in the 2 groups except for high-density lipoprotein cholesterol that was reduced in both groups. Hepatic and renal function remained normal in both groups and no major adverse effects were registered in either group.

CLINICAL IMPLICATIONS

These results may be particularly relevant for transmen experiencing cutaneous androgenic adverse events such as acne and androgenetic alopecia and in light of the development of non-5α-reduced androgens.

STRENGTHS & LIMITATIONS

The strength of this study was the randomized, double-blind PL-controlled design, while the small number of subjects was definitely the biggest limitation.

CONCLUSION

For the first time we demonstrated that the addition of DT does not impair the anabolic effects of T on muscles in transmen previously exposed to T, supporting the hypothesis that the conversion in dihydrotestosterone is not essential for this role. Gava G, Armillotta F, Pillastrini P, et al. A Randomized Double-Blind Placebo-Controlled Pilot Trial on the Effects of Testosterone Undecanoate Plus Dutasteride or Placebo on Muscle Strength, Body Composition, and Metabolic Profile in Transmen. J Sex Med 2021;18:646-655.

Sublingual Estradiol Is Associated with Higher Estrone Concentrations than Transdermal or Injectable Preparations in Transgender Women and Gender Nonbinary Adults

Purpose: Serum hormone profiles among different feminizing gender-affirming hormone therapies (GAHT) are poorly characterized. To address this gap, we described the serum estrogen profiles of three 17β-estradiol preparations, taken with or without an antiandrogen, using a novel liquid chromatography-mass spectrometry (LC-MS/MS) assay in adults taking feminizing GAHT. Methods: This was a secondary analysis of 93 healthy transgender women and gender nonbinary adults taking feminizing GAHT in a prospective cross-sectional study. Eligible participants took 17β-estradiol (sublingual tablet, transdermal patch, or intramuscular/subcutaneous injection) with or without oral spironolactone for ≥12 months before study entry. We determined serum estrone and estradiol concentrations for each hormone preparation and described the association between estrone and (1) clinically relevant estradiol concentration ranges (≤200 and >200 pg/mL) and (2) antiandrogen use. To achieve our objectives, we described our protocol for developing an LC-MS/MS assay to measure estrone and estradiol concentrations. Results: Estrone concentrations were higher among participants taking sublingual 17β-estradiol tablets compared with transdermal or injectable preparations (p < 0.0001). Estradiol concentrations were higher for injectable versus transdermal preparations (p = 0.0201), but both were similar to sublingual tablet concentrations (p > 0.05). Estradiol >200 pg/mL (vs. ≤200 pg/mL) was associated with higher estrone concentrations among participants taking sublingual 17β-estradiol, but not transdermal or injectable 17β-estradiol. We observed no association between spironolactone and estrone concentrations (p > 0.5). Conclusion: Estrone concentrations were higher among transgender women and gender nonbinary adults taking sublingual 17β-estradiol compared with transdermal or injectable preparations. The role of estrone in clinical monitoring and the influence of other antiandrogens (e.g., cyproterone acetate) on the estrogen profile remain to be determined.

Gender-Affirming Hormone Therapy and Bone Health: Do Different Regimens Influence Outcomes in Transgender Adults? A Narrative Review and Call for Future Studies

BACKGROUND

Gender-affirming hormone therapy (GAHT) influences bone health in transgender individuals. Several hormone preparations and administration routes are available for GAHT, but no studies have compared clinical and laboratory bone health measures across different GAHT regimens.

CONTENT

We searched PubMed (MEDLINE), Embase, and Google Scholar for studies measuring bone turnover markers and bone mineral density before and during GAHT in transgender adults. We summarized bone health data by hormone type and administration route (estrogen or testosterone; oral, transdermal/percutaneous, intramuscular). Among trans women, we also examined outcomes among regimens containing different adjunctive agents (antiandrogens or gonadotropin-releasing hormone analogs).

SUMMARY

Most hormone preparations maintained or increased areal bone mineral density among trans adults taking GAHT for at least 12 months from baseline. Different bone turnover markers were measured across studies, and we were unable to compare or comment on the direct influence of selected hormone preparations on these clinical laboratory measures. Larger and uniformed studies are needed to measure volumetric bone mineral density and biomarkers of bone metabolism in trans adults taking standardized GAHT regimens.

Insulin resistance in transgender individuals correlates with android fat mass

BACKGROUND

Transgender individuals receiving gender-affirming hormone therapy (GAHT) are at increased risk of adverse cardiovascular outcomes. This may be related to effects on body composition and insulin resistance.

AIMS

To examine relationships between body fat distribution and insulin resistance in transgender individuals on established GAHT.

METHODS

Comparisons of body composition (dual energy X-ray absorptiometry) and insulin resistance [Homeostasis Model of Insulin Resistance (HOMA2-IR)] were made between transgender individuals (43 trans men and 41 trans women) on established GAHT (>12 months) and age-matched cisgender controls (30 males and 48 females). Multiple linear regressions were used to examine the relationship between HOMA2-IR and fat mass with gender, adjusting for age and total duration of GAHT and Pearson correlation coefficients are reported.

RESULTS

Compared with control cisgender women, trans men had mean difference of +7.8 kg (4.0, 11.5), p < 0.001 in lean mass and higher android:gynoid fat ratio [0.2 (0.1, 0.3), p < 0.001], but no difference in overall fat mass or insulin resistance. Compared with control cisgender men, trans women had median difference in lean mass of -6.9 kg (-10.6, -3.1), p < 0.001, fat mass of +9.8 kg (3.9, 14.5), p = 0.001, lower android:gynoid fat ratio -0.1 (-0.2,-0.0), p < 0.05), and higher insulin resistance 1.6 (1.3-1.9), p < 0.001). Higher HOMA2-IR correlated with higher android (r ² = 0.712, p < 0.001) and gynoid (r ² = 0.572, p < 0.001) fat mass in both trans men and trans women.

CONCLUSION

Android fat more strongly correlates with insulin resistance than gynoid fat in transgender individuals. Higher fat mass and insulin resistance in trans women may predispose to increased cardiovascular risk. Despite adverse fat distribution, insulin resistance was not higher in trans men.

Effect of gender affirming hormones on athletic performance in transwomen and transmen: implications for sporting organisations and legislators

OBJECTIVE

To examine the effect of gender affirming hormones on athletic performance among transwomen and transmen.

METHODS

We reviewed fitness test results and medical records of 29 transmen and 46 transwomen who started gender affirming hormones while in the United States Air Force. We compared pre- and post-hormone fitness test results of the transwomen and transmen with the average performance of all women and men under the age of 30 in the Air Force between 2004 and 2014. We also measured the rate of hormone associated changes in body composition and athletic performance.

RESULTS

Participants were 26.2 years old (SD 5.5). Prior to gender affirming hormones, transwomen performed 31% more push-ups and 15% more sit-ups in 1 min and ran 1.5 miles 21% faster than their female counterparts. After 2 years of taking feminising hormones, the push-up and sit-up differences disappeared but transwomen were still 12% faster. Prior to gender affirming hormones, transmen performed 43% fewer push-ups and ran 1.5 miles 15% slower than their male counterparts. After 1 year of taking masculinising hormones, there was no longer a difference in push-ups or run times, and the number of sit-ups performed in 1 min by transmen exceeded the average performance of their male counterparts.

SUMMARY

The 15-31% athletic advantage that transwomen displayed over their female counterparts prior to starting gender affirming hormones declined with feminising therapy. However, transwomen still had a 9% faster mean run speed after the 1 year period of testosterone suppression that is recommended by World Athletics for inclusion in women's events.

Bone health of transgender adults: what the radiologist needs to know

Sex steroids are important regulators of bone development before puberty and of bone homeostasis throughout adulthood. Gender-affirming therapies with sex steroids are used in transgender and gender diverse persons for treatment of gender dysphoria, which may have profound impacts on their bone metabolism. Many studies have described variable changes in bone density and geometry in transgender cohorts. In order to provide informed guidance on the effect of gender-affirming therapy, the International Society of Clinical Densitometry issued official position statements in 2019 for the performance and interpretation of dual-energy x-ray absorptiometry in transgender and gender-diverse patients. We review the effects of gender-affirming hormone therapy on bone physiology and the changes in bone modulation that have been reported in the literature in transgender patients who have received gender-affirming therapy. We also summarize the recent guidelines for interpretation of dual energy x-ray absorptiometry as an update for the radiologist.

Effects of gender-affirming hormone therapy on insulin resistance and body composition in transgender individuals: A systematic review

BACKGROUND

Transgender individuals receiving masculinising or feminising gender-affirming hormone therapy with testosterone or estradiol respectively, are at increased risk of adverse cardiovascular outcomes, including myocardial infarction and stroke. This may be related to the effects of testosterone or estradiol therapy on body composition, fat distribution, and insulin resistance but the effect of gender-affirming hormone therapy on these cardiovascular risk factors has not been extensively examined.

AIM

To evaluate the impact of gender-affirming hormone therapy on body composition and insulin resistance in transgender individuals, to guide clinicians in minimising cardiovascular risk.

METHODS

We performed a review of the literature based on PRISMA guidelines. MEDLINE, Embase and PsycINFO databases were searched for studies examining body composition, insulin resistance or body fat distribution in transgender individuals aged over 18 years on established gender-affirming hormone therapy. Studies were selected for full-text analysis if they investigated transgender individuals on any type of gender-affirming hormone therapy and reported effects on lean mass, fat mass or insulin resistance.

RESULTS

The search strategy identified 221 studies. After exclusion of studies that did not meet inclusion criteria, 26 were included (2 cross-sectional, 21 prospective-uncontrolled and 3 prospective-controlled). Evidence in transgender men suggests that testosterone therapy increases lean mass, decreases fat mass and has no impact on insulin resistance. Evidence in transgender women suggests that feminising hormone therapy (estradiol, with or without anti-androgen agents) decreases lean mass, increases fat mass, and may worsen insulin resistance. Changes to body composition were consistent across almost all studies: Transgender men on testosterone gained lean mass and lost fat mass, and transgender women on oestrogen experienced the reverse. No study directly contradicted these trends, though several small studies of short duration reported no changes. Results for insulin resistance are less consistent and uncertain. There is a paucity of prospective controlled research, and existing prospective evidence is limited by small sample sizes, short follow up periods, and young cohorts of participants.

CONCLUSION

Further research is required to further characterise the impact of gender-affirming hormone therapy on body composition and insulin resistance in the medium-long term. Until further evidence is available, clinicians should aim to minimise risk by monitoring cardiovascular risk markers regularly in their patients and encouraging healthy lifestyle modifications.

Muscle Strength, Size, and Composition Following 12 Months of Gender-affirming Treatment in Transgender Individuals

CONTEXT

As many sports are divided in male/female categories, governing bodies have formed regulations on the eligibility for transgender individuals to compete in these categories. Yet, the magnitude of change in muscle mass and strength with gender-affirming treatment remains insufficiently explored.

OBJECTIVE

This study explored the effects of gender-affirming treatment on muscle function, size, and composition during 12 months of therapy.

DESIGN, SETTINGS, PARTICIPANTS

In this single-center observational cohort study, untrained transgender women (TW, n = 11) and transgender men (TM, n = 12), approved to start gender-affirming medical interventions, underwent assessments at baseline, 4 weeks after gonadal suppression of endogenous hormones but before hormone replacement, and 4 and 12 months after treatment initiation.

MAIN OUTCOME MEASURES

Knee extensor and flexor strength were assessed at all examination time points, and muscle size and radiological density (using magnetic resonance imaging and computed tomography) at baseline and 12 months after treatment initiation.

RESULTS

Thigh muscle volume increased (15%) in TM, which was paralleled by increased quadriceps cross-sectional area (CSA) (15%) and radiological density (6%). In TW, the corresponding parameters decreased by -5% (muscle volume) and -4% (CSA), while density remained unaltered. The TM increased strength over the assessment period, while the TW generally maintained their strength levels.

CONCLUSIONS

One year of gender-affirming treatment resulted in robust increases in muscle mass and strength in TM, but modest changes in TW. These findings add new knowledge on the magnitude of changes in muscle function, size, and composition with cross-hormone therapy, which could be relevant when evaluating the transgender eligibility rules for athletic competitions.

Fracture Risk in Trans Women and Trans Men Using Long-Term Gender-Affirming Hormonal Treatment: A Nationwide Cohort Study

Concerns about bone health in transgender people using gender-affirming hormonal treatment (HT) exist, but the fracture risk is not known. In this nationwide cohort study, we aimed to compare the fracture incidence in transgender people using long-term HT with an age-matched reference population. All adult transgender people who started HT before 2016 at our gender-identity clinic were included and were linked to a random population-based sample of 5 age-matched reference men and 5 age-matched reference women per person. Fracture incidence was determined using diagnoses from visits to hospital emergency rooms nationwide between 2013 and 2015. A total of 1089 trans women aged <50 years (mean 38 ± 9 years) and 934 trans women aged ≥50 years (mean 60 ± 8 years) using HT for median 8 (interquartile range [IQR] 3-16) and 19 (IQR 11-29) years, respectively, were included. A total of 2.4% of the trans women aged <50 years had a fracture, whereas 3.0% of the age-matched reference men (odds ratio [OR] = 0.78, 95% confidence interval [CI] 0.51-1.19) and 1.6% of the age-matched reference women (OR = 1.49, 95% CI 0.96-2.32) experienced a fracture. In trans women aged ≥50 years, 4.4% experienced a fracture compared with 2.4% of the age-matched reference men (OR = 1.90, 95% CI 1.32-2.74) and 4.2% of the age-matched reference women (OR = 1.05, 95% CI 0.75-1.49). A total of 1036 trans men (40 ± 14 years) using HT for median 9 (IQR 2-22) years were included. Fractures occurred in 1.7% of the trans men, 3.0% of the age-matched reference men (OR = 0.57, 95% CI 0.35-0.94), and 2.2% of the age-matched reference women (OR = 0.79, 95% CI 0.48-1.30). In conclusion, fracture risk was higher in older trans women compared with age-matched reference men. In young trans women, fracture risk tended to be increased compared with age-matched reference women. Fracture risk was not increased in young trans men. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Bone health in adult trans persons: an update of the literature

PURPOSE OF REVIEW

Hormonal treatment in trans persons can affect bone health. In this review, recent studies published on this topic in adults are discussed.

RECENT FINDINGS

Before starting hormonal treatment, trans women were found to have lower bone mineral density than cis men, which seems to be related to lower vitamin D concentrations and lower lean body mass, whereas this was not found in trans men. Short-term and long-term studies show that hormonal treatment does not have detrimental effects on bone mineral density in trans women and trans men. Low estradiol concentrations were associated with a decrease in bone mineral density in trans women.

SUMMARY

Based on the reassuring findings in these studies, regularly assessing bone mineral density during hormonal treatment does not seem necessary. This confirms the Endocrine Society Guideline stating that bone mineral density should be measured only when risk factors for osteoporosis exist, especially in people who stop hormonal treatment after gonadectomy. The relationship with estradiol concentrations indicate that hormone supplementation should be adequate and therapy compliance should be stimulated. As vitamin D deficiency frequently occurs, vitamin D supplementation should be considered. Future research should focus on fracture risk and long-term changes in bone geometry.

Gender-Affirming Hormone Treatment Decreases Bone Turnover in Transwomen and Older Transmen

Sex steroids play a key role in bone turnover and preserving BMD; hence, gender-affirming hormone treatment (HT) in transgender people affects bone metabolism. Most studies have looked into the effect of HT on changes in BMD; however, they do not provide insights into changes in bone metabolism caused by HT. This study investigated changes in bone turnover markers (BTMs) and sclerostin, as well as their correlations with change in BMD in transwomen and transmen during the first year of HT. Transwomen received estradiol and antiandrogens; transmen received testosterone. Sclerostin; P1NP; alkaline phosphatase (ALP); CTx; and BMD of the total hip, the femoral neck, and the lumbar spine were evaluated at baseline and after 1 year of HT. There were 121 transwomen (median age 30 years, interquartile range [IQR] 24 to 41 years) and 132 transmen (median age 24 years, IQR 21 to 33 years) included in the study. In transwomen, ALP decreased in 19% (95% CI, -21 to-16), CTx in 11% (95% CI, -18 to-4), and sclerostin in 8% (95%CI, -13 to-4) of study participants after 1 year of HT. In contrast, in transmen P1NP, ALP, and sclerostin increased in 33% (95% CI, 24 to 42), 16% (95% CI, 12 to 20), and 15% (95% CI, 10 to 20) of study participants, respectively, after 1 year of HT. No age differences were seen in transwomen, whereas in transmen aged ≥50 years a decrease in all BTMs was found in contrast with the other age groups. These transmen had low estrogen concentration at the start of HT based on their postmenopausal state before the start of HT; their estradiol concentrations increased during testosterone treatment. Changes in BTMs and BMD were weakly correlated (correlation coefficient all <0.30). To conclude, 1 year of HT resulted in decreased bone turnover in transwomen and older transmen, whereas it increased in younger transmen. The decrease in bone resorption in older transmen shows the importance of estrogen as a key regulator of bone turnover. © 2019 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc.

Bone Densitometry in Transgender and Gender Non-Conforming (TGNC) Individuals: 2019 ISCD Official Position

The indications for initial and follow-up bone mineral density (BMD) in transgender and gender nonconforming (TGNC) individuals are poorly defined, and the choice of which gender database to use to calculate Z-scores is unclear. Herein, the findings of the Task Force are presented after a detailed review of the literature. As long as a TGNC individual is on standard gender-affirming hormone treatment, BMD should remain stable to increasing, so there is no indication to monitor for bone loss or osteoporosis strictly on the basis of TGNC status. TGNC individuals who experience substantial periods of hypogonadism (>1 yr) might experience bone loss or failure of bone accrual during that time, and should be considered for baseline measurement of BMD. To the extent that this hypogonadism continues over time, follow-up measurements can be appropriate. TGNC individuals who have adequate levels of endogenous or exogenous sex steroids can, of course, suffer from other illnesses that can cause osteoporosis and bone loss, such as hyperparathyroidism and steroid use; they should have measurement of BMD as would be done in the cisgender population. There are no data that TGNC individuals have a fracture risk different from that of cisgender individuals, nor any data to suggest that BMD predicts their fracture risk less well than in the cisgender population. The Z-score in transgender individuals should be calculated using the reference data (mean and standard deviation) of the gender conforming with the individual's gender identity. In gender nonconforming individuals, the reference data for the sex recorded at birth should be used. If the referring provider or the individual requests, a set of "male" and "female" Z-scores can be provided, calculating the Z-score against male and female reference data, respectively.

Bone geometry and trabecular bone score in transgender people before and after short- and long-term hormonal treatment

BACKGROUND

Gender-affirming hormonal treatment (HT) in adult transgender people influences bone mineral density (BMD). Besides BMD, bone geometry and trabecular bone score are associated with fracture risk. However, it is not known whether bone geometry and TBS changes during HT.

PURPOSE

To investigate the bone geometry and TBS in adult transgender people at different time points, up to 25 years, of HT.

METHODS

A total of 535 trans women and 473 trans men were included, who were divided into three groups at time of their DXA: 20-29 years, 30-39 years, and 40-59 years. Subsequently, each group was divided into different HT durations: baseline, or after 5, 15, or 25 years of HT. Hip structure analysis was performed to measure subperiosteal width, endocortical diameter, average cortical thickness, and section modulus. TBS was calculated based on lumbar spine DXA images.

RESULTS

In trans women in all age groups and in young trans men, no differences were observed in periosteal width, endocortical diameter, average cortical thickness, and section modulus for different durations of HT. In trans men aged 40-59 years, subperiosteal width, endocortical diameter, and section modulus were slightly higher in the groups who were using HT compared to the (peri- or postmenopausal) baseline group. In younger trans women, TBS tended to be higher in those using HT compared to the baseline groups, and in older trans women TBS was higher in those using HT for 25 years versus baseline (+0.04, 95%CI +0.00; +0.08). In younger trans men, TBS tended to be lower in those who used HT compared to the baseline groups, and in older trans men TBS was lower in those using 5 years HT versus baseline (-0.05, 95%CI -0.08; -0.01).

CONCLUSION

No differences in cortical bone geometry parameters were found during different HT-durations. TBS increased in trans women and decreased in trans men, indicating that estrogens have positive effects on TBS. These data may be helpful in determining what sex reference values for calculating T-scores and Z-scores in adult transgender people should be used.

Health considerations for transgender women and remaining unknowns: a narrative review

Transgender (trans) women (TW) were assigned male at birth but have a female gender identity or gender expression. The literature on management and health outcomes of TW has grown recently with more publication of research. This has coincided with increasing awareness of gender diversity as communities around the world identify and address health disparities among trans people. In this narrative review, we aim to comprehensively summarize health considerations for TW and identify TW-related research areas that will provide answers to remaining unknowns surrounding TW's health. We cover up-to-date information on: (1) feminizing gender-affirming hormone therapy (GAHT); (2) benefits associated with GAHT, particularly quality of life, mental health, breast development and bone health; (3) potential risks associated with GAHT, including cardiovascular disease and infertility; and (4) other health considerations like HIV/AIDS, breast cancer, other tumours, voice therapy, dermatology, the brain and cognition, and aging. Although equally deserving of mention, feminizing gender-affirming surgery, paediatric and adolescent populations, and gender nonbinary individuals are beyond the scope of this review. While much of the data we discuss come from Europe, the creation of a United States transgender cohort has already contributed important retrospective data that are also summarized here. Much remains to be determined regarding health considerations for TW. Patients and providers will benefit from larger and longer prospective studies involving TW, particularly regarding the effects of aging, race and ethnicity, type of hormonal treatment (e.g. different oestrogens, anti-androgens) and routes of administration (e.g. oral, parenteral, transdermal) on all the topics we address.

Transgender bone health

Gonadal sex steroids play a pivotal role in bone health. Medical and surgical therapies for gender dysphoria in both adolescents and adults can lead to skeletal changes. This review evaluates the literature on transgender bone health, and how the data can be translated into clinical practice.