A European Network for the Investigation of Gender Incongruence in adolescents

BACKGROUND

Knowledge regarding the effects and side effects of gender-affirming hormone therapy (GAHT) in adults is rapidly growing, partly through international research networks such as the European Network for the Investigation of Gender Incongruence (ENIGI). However, data on the effects of puberty suppression (PS) and GAHT in transgender and gender diverse (TGD) youth are limited, although these data are of crucial importance, given the controversies surrounding this treatment.

AIM

We sought to present a detailed overview of the design of the ENIGI Adolescents study protocol, including the first baseline data.

METHODS

The ENIGI Adolescents study is an ongoing multicenter prospective cohort study. This study protocol was developed by 3 European centers that provide endocrine care for TGD adolescents and were already part of the ENIGI collaboration: Amsterdam, Ghent, and Florence.

OUTCOMES

Study outcomes include physical effects and side effects, laboratory parameters, bone mineral density, anthropometric characteristics, attitudes toward fertility and fertility preservation, and psychological well-being, which are measured in the study participants during PS and GAHT, up to 3 years after the start of GAHT.

RESULTS

Between November 2021 and May 2023, 172 TGD adolescents were included in the ENIGI Adolescents protocol, of whom 51 were assigned male at birth (AMAB) and 121 were assigned female at birth (AFAB); 3 AFAB participants reported a nonbinary gender identification. A total of 76 participants were included at the start of PS, at a median (IQR) age of 13.7 (12.9-16.5) years in AMAB and 13.5 (12.4-16.1) years in AFAB individuals. The remaining 96 participants were included at start of GAHT, at a median (IQR) age of 15.9 (15.1-17.4) years in AFAB and 16.0 (15.1-16.8) years in AMAB individuals. At the time of this report the study was open for inclusion and follow-up measurements were ongoing.

CLINICAL IMPLICATIONS

In response to the rising demand for gender-affirming treatment among TGD youth, this ongoing study is fulfilling the need for prospective data on the effects and safety of PS and GAHT, thus providing a foundation for evidence-based healthcare decisions.

STRENGTHS AND LIMITATIONS

This study has a strong multicenter, prospective design that allows for systematic data collection. The use of clinical and self-reported data offers a broad range of outcomes to evaluate. Nevertheless, the burden of additional measurements and questionnaires may lead to withdrawal or lower response rates. Few participants with a non-binary gender identity have been included.

CONCLUSION

With the ENIGI Adolescents study we aim to create a comprehensive dataset that we can use for a wide range of studies to address current controversies and uncertainties and to improve healthcare for TGD adolescents.

Mortality trends over five decades in adult transgender people receiving hormone treatment: a report from the Amsterdam cohort of gender dysphoria

BACKGROUND

Increased mortality in transgender people has been described in earlier studies. Whether this increased mortality is still present over the past decades is unknown. Therefore, we aimed to investigate trends in mortality over five decades in a large cohort of adult transgender people in addition to cause-specific mortality.

METHODS

We did a retrospective cohort study of adult transgender people who visited the gender identity clinic of Amsterdam University Medical Centre in the Netherlands. Data of transgender people who received hormone treatment between 1972 and 2018 were linked to Statistics Netherlands. People were excluded if they used alternating testosterone and oestradiol treatment, if they started treatment younger than age 17 years, or if they had ever used puberty-blockers before gender-affirming hormone treatment. Standardised mortality ratios (SMRs) were calculated using general population mortality rates stratified by age, calendar period, and sex. Cause-specific mortality was also calculated.

FINDINGS

Between 1972 and 2018, 8831 people visited the gender identity clinic. 4263 were excluded from the study for a variety of reasons, and 2927 transgender women and 1641 transgender men were included in the study, with a total follow-up time of 40 232 person-years for transgender women and 17 285 person-years for transgender men. During follow-up, 317 (10·8%) transgender women died, which was higher than expected compared with general population men (SMR 1·8, 95% CI 1·6-2·0) and general population women (SMR 2·8, 2·5-3·1). Cause-specific mortality in transgender women was high for cardiovascular disease, lung cancer, HIV-related disease, and suicide. In transgender men, 44 people (2·7%) died, which was higher than expected compared with general population women (SMR 1·8, 95% CI 1·3-2·4) but not general population men (SMR 1·2, 95% CI 0·9-1·6). Cause-specific death in transgender men was high for non-natural causes of death. No decreasing trend in mortality risk was observed over the five decades studied.

INTERPRETATION

This observational study showed an increased mortality risk in transgender people using hormone treatment, regardless of treatment type. This increased mortality risk did not decrease over time. The cause-specific mortality risk because of lung cancer, cardiovascular disease, HIV-related disease, and suicide gives no indication to a specific effect of hormone treatment, but indicates that monitoring, optimising, and, if necessary, treating medical morbidities and lifestyle factors remain important in transgender health care.

FUNDING

None.

Sustained Breast Development and Breast Anthropometric Changes in 3 Years of Gender-Affirming Hormone Treatment

CONTEXT

Breast development is important for most trans women. An important limitation of current breast development measurement methods is that these do not allow for 3D volume analyses.

OBJECTIVES

To examine breast development and change in anthropometry during the first 3 years of gender-affirming hormone treatment using 3D imaging. Associations with clinical or laboratory parameters and satisfaction with the gained breast development were also studied.

DESIGN

Prospective cohort study.

SETTING

Specialized tertiary gender identity clinic in Amsterdam, the Netherlands.

PARTICIPANTS

Participants were 69 adult trans women with a median age of 26 years (interquartile range, 21-38).

INTERVENTIONS

Gender-affirming hormone treatment.

MAIN OUTCOME MEASURES

Volumetric and anthropometric breast development and satisfaction.

RESULTS

Breast volume increased by 72 cc (95% confidence interval [CI], 48-97) to 100 cc (standard deviation 48). This resulted in a cup-size <A-cup in 71% of the participants. Although the change in breast-chest difference plateaued after approximately 9 months, sustained increase in breast volume was observed during the 3-year observation period. Sternal notch to nipple distance increased by 1.3 cm (95% CI, 0.9-1.7) and internipple distance increased by 1.0 cm (95% CI, 0.4-1.5). At least 58% of trans women were satisfied with the gained breast size.

CONCLUSIONS

Sustained breast growth and development during hormone treatment was observed during the full 3-year observation period. The breasts of trans women are positioned more laterally and caudally on the chest compared with cis women. Although modest breast volumes were observed, breast development was satisfactory to most trans women.

Testosterone effects on functional amygdala lateralization: A study in adolescent transgender boys and cisgender boys and girls

The influence of testosterone on the development of human brain lateralization has been subject of debate for a long time, partly because studies investigating this are necessarily mostly correlational. In the present study we used a quasi-experimental approach by assessing functional brain lateralization in trans boys (female sex assigned at birth, diagnosed with Gender Dysphoria, n = 21) before and after testosterone treatment, and compared these results to the functional lateralization of age-matched control groups of cisgender boys (n = 20) and girls (n = 21) around 16 years of age. The lateralization index of the amygdala was determined with functional magnetic resonance imaging (fMRI) during an emotional face matching task with angry and fearful faces, as the literature indicates that boys show more activation in the right amygdala than girls during the perception of emotional faces. As expected, the lateralization index in trans boys shifted towards the right amygdala after testosterone treatment, and the cumulative dose of testosterone treatment correlated significantly with amygdala lateralization after treatment. However, we did not find any significant group differences in lateralization and endogenous testosterone concentrations predicted rightward amygdala lateralization only in the cis boys, but not in cis girls or trans boys. These inconsistencies may be due to sex differences in sensitivity to testosterone or its metabolites, which would be a worthwhile course for future studies.

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.

Kisspeptin Expression in the Human Infundibular Nucleus in Relation to Sex, Gender Identity, and Sexual Orientation

CONTEXT

Since the discovery of its central role in reproduction, our functional neuroanatomical knowledge of the hypothalamic kisspeptin system is predominantly based on animal studies. Although sex differences in kisspeptin expression have been shown in humans in adulthood, the developmental origin of this sex difference is unknown.

OBJECTIVES

Our objectives were to determine the following: 1) when during development the sex difference in kisspeptin expression in the infundibular nucleus would emerge and 2) whether this sex difference is related to sexual orientation or transsexuality.

DESIGN AND SETTING

Postmortem hypothalamic tissues were collected by The Netherlands Brain Bank, and sections were stained for kisspeptin by immunohistochemistry.

PATIENTS

Hypothalami of 43 control subjects were categorized into three periods: infant/prepubertal (six girls, seven boys), adult (11 women, seven men), and elderly (six aged women, six aged men). Eight male-to-female (MTF) transsexuals, three HIV(+) heterosexual men, and five HIV(+) homosexual men were also analyzed.

MAIN OUTCOME MEASURE

We estimated the total number of kisspeptin-immunoreactive neurons within the infundibular nucleus.

RESULTS

Quantitative analysis confirmed that the human infundibular kisspeptin system exhibits a female-dominant sex difference. The number of kisspeptin neurons is significantly greater in the infant/prepubertal and elderly periods compared with the adult period. Finally, in MTF transsexuals, but not homosexual men, a female-typical kisspeptin expression was observed.

CONCLUSIONS

These findings suggest that infundibular kisspeptin neurons are sensitive to circulating sex steroid hormones throughout life and that the sex reversal observed in MTF transsexuals might reflect, at least partially, an atypical brain sexual differentiation.

Puberty suppression and executive functioning: An fMRI-study in adolescents with gender dysphoria

Adolescents with gender dysphoria (GD) may be treated with gonadotropin releasing hormone analogs (GnRHa) to suppress puberty and, thus, the development of (unwanted) secondary sex characteristics. Since adolescence marks an important period for the development of executive functioning (EF), we determined whether the performance on the Tower of London task (ToL), a commonly used EF task, was altered in adolescents with GD when treated with GnRHa. Furthermore, since GD has been proposed to result from an atypical sexual differentiation of the brain, we determined whether untreated adolescents with GD showed sex-atypical brain activations during ToL performance. We found no significant effect of GnRHa on ToL performance scores (reaction times and accuracy) when comparing GnRHa treated male-to-females (suppressed MFs, n=8) with untreated MFs (n=10) or when comparing GnRHa treated female-to-males (suppressed FMs, n=12) with untreated FMs (n=10). However, the suppressed MFs had significantly lower accuracy scores than the control groups and the untreated FMs. Region-of-interest (ROI) analyses showed significantly greater activation in control boys (n=21) than control girls (n=24) during high task load ToL items in the bilateral precuneus and a trend (p<0.1) for greater activation in the right DLPFC. In contrast, untreated adolescents with GD did not show significant sex differences in task load-related activation and had intermediate activation levels compared to the two control groups. GnRHa treated adolescents with GD showed sex differences in neural activation similar to their natal sex control groups. Furthermore, activation in the other ROIs (left DLPFC and bilateral RLPFC) was also significantly greater in GnRHa treated MFs compared to GnRHa treated FMs. These findings suggest that (1) GnRHa treatment had no effect on ToL performance in adolescents with GD, and (2) pubertal hormones may induce sex-atypical brain activations during EF in adolescents with GD.

A genetic analysis of coffee consumption in a sample of Dutch twins

Caffeine is by far the most commonly used psychoactive substance. Caffeine is consumed regularly as an ingredient of coffee. Coffee consumption and coffee preference was explored in a sample of 4,495 twins (including 1,231 pairs) registered with the Netherlands Twin Registry. Twin resemblance was assessed by tetrachoric correlations and the influence of both genetic and environmental factors was explored with model fitting analysis in MX. Results showed moderate genetic influences (39%) on coffee consumption. The remaining variance was explained by shared environmental factors (21%) and unique environmental factors (40%). The variance in coffee preference (defined as the proportion of coffee consumption relative to the consumption of coffee and tea in total) was explained by genetic factors (62%) and unique environmental factors (38%).