Muscle function following testosterone replacement in men on opioid therapy for chronic non-cancer pain: A randomized controlled trial

Muscle strength changes and physical activity during gender-affirming hormone therapy: A systematic review

BACKGROUND

Higher muscle strength is associated with improved overall health and lower mortality. Muscle strength changes during gender-affirming hormone therapy is possibly linked to gender-affirming hormone therapy modality, age at initiation, gender-affirming hormone therapy duration, and physical activity.

AIM

To review published literature on muscle strength changes during gender-affirming hormone therapy.

METHODS

Studies were included if they met the PICOS criteria; P: transgender individuals ≥18 years, I: gender-affirming hormone therapy, C: gender-affirming hormone therapy-naïve transgender persons or cisgender controls, O: muscle strength and physical activity in relation to muscle strength, S: prospective cohorts or cross-sectional.

RESULTS

Fifteen studies with data on 1206 transgender persons (722 transmasculine persons, median age 23-37 years and 484 transfeminine persons, median age 27-41 years) were included. Prospective design was used in eight out of 15 studies (two out of eight on transmasculine, two out of eight on transfeminine, and four out of eight on both) and seven out of 15 were cross-sectional (two out of seven on transmasculine, four out of seven on transfeminine, and one out of seven on both). Isometric elbow flexion/extension, lower body strength, and handgrip strength were assessed in one out of 15 studies, four out of 15, and 12 out of 15 studies, respectively. Bias rating was moderate to high.

PROSPECTIVE STUDIES

Masculinizing gender-affirming hormone therapy resulted in increased (four out of six studies) or unchanged (two out of six studies) muscle strength, while feminizing gender-affirming hormone therapy resulted in decreased (three out of six studies) or unchanged (three out of six studies) muscle strength. Muscle strength changes mainly occurred during the first year after initiating gender-affirming hormone therapy and age at initiation had no impact.

CROSS-SECTIONAL STUDIES

Transmasculine and transfeminine persons had higher strength compared with cisgender women, but lower strength than cisgender men. Physical activity was unchanged during gender-affirming hormone therapy in five out of prospective studies, while transfeminine persons were less physically active than cisgender men in five out of five prospective studies.

CONCLUSION

Muscle strength appeared to increase during masculinizing gender-affirming hormone therapy and decrease during feminizing gender-affirming hormone therapy, whereas physical activity was unchanged. Given high risk of bias, more research is necessary. Improving transgender care requires engagement of transgender persons in physical activity.

The causal impact of bioavailable testosterone levels on osteoarthritis: a bidirectional Mendelian randomized study

BACKGROUND

It has been shown that low testosterone levels are associated with the development of osteoarthritis (OA). In our study, we aimed to investigate a bidirectional causal relationship between bioavailable testosterone levels and OA using Mendelian randomization (MR) analysis.

METHODS

In our study, the datasets from publicly available genome-wide association study (GWAS) were adopted, including the OA-related dataset (ukb-b-14486) and the bioavailable testosterone levels-related dataset (ebi-a-GCST90012104). The UKB-B-14,486 dataset contains 462,933 samples in total, including 38,472 OA samples, 424,461 control samples, and 9,851,867 SNPs, all collected from the European population in 2018. Additionally, the EBI-A-GCST90012104 dataset includes 382,988 samples and 16,137,327 SNPs, which reflect data from the European population in 2020. In total, five methods were utilized, namely MR Egger, Weighted median, Inverse variance weighted (IVW), Simple mode, and Weighted mode. Among them, IVW was the main analytical method. Additionally, the sensitivity analysis was carried out through the heterogeneity test, the horizontal pleiotropy test, and the Leave-One-Out (LOO) method.

RESULTS

The result of forward MR analysis demonstrated that bioavailable testosterone levels were considerably relevant to OA, and were a risk factor for OA (OR = 1.01, 95% CI: [1.00, 1.02], P = 0.02). However, through reverse MR analysis, we did not find a causal relationship between OA and bioavailable testosterone levels. Moreover, the results of the sensitivity analysis suggested that our results were reliable.

CONCLUSION

The results of our study supported a causal relationship between bioavailable testosterone levels and OA.

Testosterone levels positively linked to muscle mass but not strength in adult males aged 20-59 years: a cross-sectional study

Background

The relationship between testosterone levels and muscle mass and strength remains contentious. This study aimed to explore the relationship among total serum testosterone levels, muscle mass, and strength in young to middle-aged adults.

Methods

The analysis included 4,495 participants (age 39.2 ± 0.2 years, mean ± SE) from the National Health and Nutrition Examination Survey conducted between 2011 and 2014. Weighted regression models were used to assess the association of testosterone levels with muscle mass and strength.

Results

For male participants, log2-transformed testosterone levels were positively associated with appendicular lean mass adjusted for body mass index (β: 0.05, 95% confidence interval [CI]: 0.03-0.07, P < 0.001) and negatively associated with low muscle mass (odds ratio: 0.40, 95% CI: 0.24-0.67, P = 0.006). However, no significant association was found between testosterone levels and grip strength (β: 1.16, 95% CI: 0.26 to 2.58, P = 0.086) or low muscle strength (odds ratio: 0.51, 95% CI: 0.25-1.04, P = 0.059). For female participants, no significant association was observed between testosterone levels and muscle mass (β: 0.01, 95% CI: 0.02 to -0.01, P = 0.294) or muscle strength (β: 0.14, 95% CI: 0.45 to 0.73, P = 0.508). Restricted cubic spline analysis revealed a linear relationship between total testosterone levels and appendicular lean mass adjusted for body mass index in male participants (nonlinear: P = 0.367).

Conclusion

Our study indicates that testosterone levels are positively associated with muscle mass but not with muscle strength in young to middle-aged males.

Exogenous Opioids and the Human Endocrine System: An Endocrine Society Scientific Statement

The use and misuse of opioids are a growing global problem. Although the effects of these drugs on the human endocrine system have been studied for decades, attention on their related clinical consequences, particularly on the hypothalamic-pituitary system and bone health, has intensified over recent years. This Statement appraises research data related to the impact of opioids on the gonadal and adrenal function. Whereas hypogonadism is well recognized as a side effect of opioids, the significance of their inhibitory actions on the hypothalamic-pituitary-adrenal system and the occurrence of clinically relevant adrenal insufficiency is not fully elucidated. The often-inconsistent results of studies investigating how opioids affect the secretion of GH, prolactin, arginine vasopressin, and oxytocin are assessed. The accumulating evidence of opioid actions on bone metabolism and their negative sequelae on bone mineral density and risk of fracture are also reviewed. In each section, available data on diagnostic and management approaches for opioid endocrine sequelae are described. This Statement highlights a plethora of gaps in research associated with the effects and clinical consequences of opioids on the endocrine system. It is anticipated that addressing these gaps will improve the care of people using or misusing opioids worldwide. The Statement is not intended to serve as a guideline or dictate treatment decisions.

Cardiovascular safety of testosterone replacement therapy in men: an updated systematic review and meta-analysis

INTRODUCTION

The cardiovascular (CV) safety of testosterone (T) replacement therapy (TRT) is still conflicting. Recent data suggested a TRT-related increased risk of atrial fibrillation (AF). The aim of this study was to systematic review and meta-analyze CV risk related to TRT as derived from placebo controlled randomized trials (RCTs).

AREAS COVERED

An extensive Medline, Embase, and Cochrane search was performed. All placebo-controlled RCTs reporting data on TRT-related CV safety were considered. To better analyze the role of T on AF, population-based studies investigating the relationship between endogenous circulating T levels and AF incidence were also included and analyzed.

EXPERT OPINION

Out of 3.615, 106 studies were considered, including 8.126 subjects treated with TRT and 7.310 patients allocated to placebo. No difference between TRT and placebo was observed when major adverse CV events were considered. Whereas the incidence of non-fatal arrhythmias and AF was increased in the only trial considering CV safety as the primary endpoint, this was not confirmed when all other studies were considered (MH-OR 1.61[0.84;3.08] and 1.44[0.46;4.46]). Similarly, no relationship between endogenous T levels and AF incidence was observed after the adjustment for confounders Available data confirm that TRT is safe and it is not related to an increased CV risk.

Percent body fat was negatively correlated with Testosterone levels in male

BACKGROUND

Lower testosterone levels in men have been consistently associated with metabolic abnormalities, particularly obesity. This study aims to investigate the relationship between testosterone and obesity by analyzing the correlation between testosterone levels and body fat percentage using data from the NHANES (National Health and Nutrition Examination Survey) database.

METHODS

The study included a total of 5959 participants from the NHANES 2011-2016. Multivariable linear regression models were used to assess the association between testosterone levels and body composition parameters, including total percent fat (TPF), android percent fat (APF), gynoid percent fat (GPF), android to gynoid ratio (A/G), and lean mass percent (LMP). Subgroup analyses stratified by sex were conducted using multivariable linear regression. To account for potential non-linear relationships, fitted smoothing curves and generalized additive models were utilized. A separate analysis of participants with a BMI ≥ 30 kg/m2 was conducted to validate the conclusions.

RESULT

Among males, testosterone levels showed a significant negative correlation with TPF (β = -11.97, P <0.0001), APF (β = -9.36, P<0.0001), GPF (β = -10.29, P <0.0001), and A/G (β = -320.93, P<0.0001), while a positive correlation was observed between LMP and testosterone levels (β = 12.62, P<0.0001). In females, a contrasting pattern emerged in the relationship between testosterone and body fat, but no significant correlation was found between testosterone and body composition in obese women.

CONCLUSIONS

The findings of this study support a negative association between body fat and testosterone levels in males.

Cardiovascular Outcomes of Hypogonadal Men Receiving Testosterone Replacement Therapy: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To investigate the impact of testosterone replacement therapy (TRT) on cardiovascular outcomes in hypogonadal men.

METHODS

A meta-analysis of 26 randomized controlled trials involving 10 941 participants was conducted. Various clinical outcomes, including all-cause mortality, cardiovascular-related mortality, myocardial infarction, stroke, congestive heart failure, atrial fibrillation, pulmonary embolism, and venous thrombosis, were assessed.

RESULTS

No statistically significant differences were observed between the TRT group and the control group in terms of these clinical outcomes. Sensitivity analysis and publication bias assessment supported the robustness of the findings. Meta-regression analysis found no significant associations between clinical outcomes and potential covariates, including age, diabetes, hypertension, dyslipidemia, and smoking.

DISCUSSION

Previous research on TRT and cardiovascular events, with comparisons to studies like the Testosterone Trials and the studies conducted by Vigen et al, Finkle et al, Layton et al, and Wallis et al, is provided. The significance of the systematic review and meta-analysis approach is emphasized, particularly its exclusive focus on hypogonadal patients.

CONCLUSION

This study offers reassurance that TRT does not increase mortality risk or worsen cardiovascular outcomes in hypogonadal men. However, further research, especially long-term studies involving diverse populations, is essential to strengthen the evidence base and broaden the applicability of these findings.

Testosterone administration enhances the expectation and perception of painful and non-painful somatosensory stimuli

The influence of testosterone on pain perception remains inconsistent in the literature. This randomized, placebo-controlled, double-blind, crossover study investigated the effect of testosterone administration on perception and expectation of electrocutaneous stimulus. Thirty healthy male participants received a single dose of testosterone in one session and a placebo in the other session. For each session, they completed a pain-rating task in which a predictability cue was inserted before a painful or non-painful electocutaneous stimulus delivery, while neural activity was simultaneously recorded by a 64-channel electroencephalographic (EEG) system. Expected and perceived pain ratings, as well as event-related potentials (ERPs) to electocutaneous stimuli and prestimulus EEG oscillatory activities while expecting upcoming electocutaneous stimuli were comprehensively compared between testosterone and placebo sessions. Compared with the placebo session, participants in the testosterone session reported greater pain rating and exhibited greater amplitude of N1 component on ERPs when perceiving both painful and non-painful electrocutaneous stimuli. Mediation analysis revealed that testosterone enhanced the pain-intensity ratings via the N1 response to the electrocutaneous stimulus. Upon viewing the predictability cues after testosterone administration, expected pain intensity increased and spontaneous low-frequency α-oscillation power in the frontal region decreased. These results provide evidence that testosterone enhanced perception and expectation of somatosensory events, and that this was a general effect rather than pain-specific. A plausible explanation for these findings is that testosterone acts to increase vigilance and sustained attention levels, as evidenced by the decreased α-oscillation power. Thus, our findings support a causal role for testosterone in heightening the biological salience of incoming somatosensory information.