Symptomatic androgen deficiency develops only when both total and free testosterone decline in obese men who may have incident biochemical secondary hypogonadism: Prospective results from the EMAS

European Association of Urology Guidelines on Male Sexual and Reproductive Health: 2025 Update on Male Infertility

BACKGROUND AND OBJECTIVE

To present a summary of the updated 2025 European Association of Urology (EAU) Guidelines on Sexual and Reproductive Health (SRH) on male infertility, providing practical recommendations on the clinical work-up with a focus on diagnosis, treatment and follow-up.

METHODS

For the 2025 SRH guidelines, new and relevant evidence was identified, collated, and appraised via a structured assessment of the literature. Databases searched included Medline, EMBASE, and the Cochrane Libraries. Recommendations within the guidelines were developed by the panel to prioritise clinically important care decisions. The strength of each recommendation was determined according to a balance between desirable and undesirable consequences of alternative management strategies, the quality of the evidence (including the certainty of estimates), and the nature and variability of patient values and preferences.

KEY FINDINGS AND LIMITATIONS

Key recommendations emphasise the importance of a thorough urological assessment of all men seeking medical help for fertility problems to ensure appropriate treatment. The guidelines also stress the clinical relevance of a parallel investigation of the female partner during the diagnostic and management work-up of the infertile couple, to promote shared-decision making in terms of timing and therapeutic strategies. Furthermore, the guidelines recommend to counsel all infertile men and men with abnormal semen parameters on the associated health risks. Key changes in the male infertility guidelines for 2025 include: the addition of two new sections addressing exome sequencing and probiotic treatment; and significant update of the evidence base and recommendations for the diagnostic work-up of male infertility.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This overview of the 2025 SHR guidelines offers valuable insights into the diagnosis, classification, treatment and follow-up of male factor infertility and are designed for effective integration into clinical practice.

SHBG Gene Polymorphisms and Their Influence on Serum SHBG, Total and Free Testosterone Concentrations in Men

CONTEXT

Genetic variation in SHBG structure may affect estimates of sex steroid exposure by altering the affinity of the protein for its ligand. Consequently, free hormone calculations assuming constant binding affinity may, for certain genetic variations, lead to incorrect diagnoses if genetic variation is not taken into consideration.

OBJECTIVE

To investigate the effects of genetic variation in SHBG on calculated and measured serum free testosterone (T) in men.

DESIGN, SETTING AND PARTICIPANTS

Population-based sibling-pair study in 999 healthy men aged 25 to 45 (mean, 34.5) years.

MAIN OUTCOME MEASURES

Genotyping using microarray (Illumina) for single-nucleotide polymorphism (SNPs) suggested to affect binding affinity and/or concentration of SHBG or T. SHBG concentrations were measured using immunoassay and in a subset (n = 32) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Total T was measured using LC-MS/MS. Free T was calculated and in a subset (n = 314) measured directly using LC-MS/MS after equilibrium dialysis.

RESULTS

Allelic frequencies of analyzed SNPs ranged from 0.5% to 58.2%. Compared to wild-type, SHBG concentrations were lower in rs6258 heterozygotes (-24.7%; P < .05) and higher in rs6259 heterozygotes, rs727428 homozygotes, and carriers of rs1799941 (+10.8 to 23.1%; all P < .05). Total T was higher in rs727428 homozygotes and carriers of rs5934505, rs1799941and rs6259 (+3.9 to 21.4%; all P < .05). No clear effects on measured free T were found, except for a trend toward higher values in rs6259 homozygotes, significant for calculated free T (+18.7%; P < .05) in the larger global study population.

CONCLUSION

In these men, analyzed SNPs were relatively prevalent and affected serum concentrations of total T and SHBG but not calculated or measured free T except for a higher trend in rs6259 homozygotes.

Integrated stress response mediates HSP70 to inhibit testosterone synthesis in aging testicular Leydig cells

The integrated stress response (ISR) is implicated in age-related diseases, while the molecular chaperone heat shock protein 70 (HSP70) can facilitate proper protein folding. However, the regulatory mechanism of ISR in insufficient testosterone synthesis of aging Leydig cells (LCs) remains unclear. This study aims to elucidate the regulatory role of ISR in inadequate testosterone synthesis of aging LCs. We observed a positive correlation between testosterone and HSP70 levels, which were found to be decreased in elderly men. ISR was detected in testicular tissue from old mice. The expression of testosterone synthesis related protein and the content of testosterone decreased in testicular tissue of old mice. Conversely, inhibition of the integrated stress response in testicular tissue led to an increase in steroid synthase expression among old mice. Furthermore, inhibiting ISR specifically within aging LCs resulted in enhanced protein translation efficiency and increased expression levels of new HSP70 and steroidogenic acute regulatory protein (StAR). These findings suggest that ISR occurrence within aging LCs affects StAR protein expression through regulation of HSP70-mediated translation, consequently impairing testosterone synthesis.

Use of calculated free testosterone in men: advantages and limitations

PURPOSE OF REVIEW

Due to technical requirements and high cost, equilibrium dialysis-free testosterone (T) measurements are not commonly available in clinical practice. Clinicians rely on calculated free T (cFT) as a proxy. This review discusses using free T as a second-line assessment, highlighting its relevance in preventing misdiagnosis and overtreatment of male hypogonadism.

RECENT FINDINGS

While there is consensus on measuring total T - comprising sex hormone-binding globulin (SHBG)-bound, albumin-bound, and free T - as a first step in diagnosing male hypogonadism, evidence confirms that aging and conditions like obesity influence both total T and SHBG levels. Furthermore, low free T has been associated with symptoms of androgen deficiency, even in men with normal total T. Clinicians should, however, be aware of limitations of free T calculations, particularly the lack of standardization. Recent developments include establishing age-stratified free T reference ranges measured by equilibrium dialysis.

SUMMARY

Free T remains a subject of longstanding controversy. Factors such as age and obesity can alter total T and SHBG levels. Free T serves as a second-line indicator of androgen exposure, taking SHBG fluctuations into account. Given that commonly used free T calculators only provide approximations of free T, there is a need to further standardize free T calculators.

Mechanisms of erectile dysfunction induced by aging: A comprehensive review

BACKGROUND

With the increasing trend ofpopulation aging, erectile dysfunction (ED) among elderly men has emerged as apressing health concern. Despite extensive research on the relationship betweenED and aging, ongoing discoveries and evidence continue to arise.

OBJECTIVE

Through this comprehensiveanalysis, we aim to provide a more nuanced theoretical framework for thedevelopment of preventive and therapeutic strategies for senile ED, ultimatelyenhancing the quality of life for elderly men.

METHODS

This review delves deeper into thecore mechanisms underlying ED in the context of aging and offers acomprehensive overview of published meta-analyses and systematic reviewspertinent to these conditions.

RESULTS AND CONCLUSION

Our findings revealthat local structural damage to the penis, vascular dysfunction, neuronalinjury, hormonal alterations, other physiological changes, and psychologicalbarriers all play pivotal roles in the pathogenesis of aging-related ED.Furthermore, more than 20 diseases closely associated with aging have beenimplicated in the occurrence of ED, further compounding the complexity of thisissue.

Preoperative high serum total testosterone levels predict preserved postoperative sexual function in patients after nerve-sparing robot-assisted radical prostatectomy

OBJECTIVE

To assess the association among preoperative total testosterone levels, postoperative sexual function, and prognosis after robot-assisted radical prostatectomy.

METHODS

Patients who underwent robot-assisted radical prostatectomy in our institution were included in the study. Based on preoperative total testosterone levels, they were divided into low (<3.0 ng/mL) and high (≥3.0 ng/mL) total testosterone groups. Sexual function was evaluated using the International Index of Erectile Function scores, Expanded Prostate Cancer Index Composite scores, and the potency rate from preoperatively to 12 months after surgery. Oncological outcomes were evaluated based on biochemical recurrence.

RESULTS

Out of 233 patients included, no significant difference in sexual function was found between the high (n = 183) and the low (n = 50) total testosterone groups at any point before or after surgery. However, in nerve-sparing cases, preservation in postoperative sexual function was observed only in the high total testosterone group (International Index of Erectile Function scores and Expanded Prostate Cancer Index Composite sexual function scores, at any point after surgery, p < 0.05; potency rate, at 3, 6, and 12 months after surgery; p < 0.05). Additionally, the high total testosterone group showed better biochemical recurrence-free survival than the low total testosterone group (p = 0.008).

CONCLUSIONS

In the high total testosterone group, preservation in sexual function was observed after the nerve-sparing procedure, while the biochemical recurrence rate was low. Therefore, patients with high levels of total testosterone may be advised to consider nerve-sparing interventions.

Management of male obesity-related secondary hypogonadism: A clinical update

The global obesity pandemic has resulted in a rise in the prevalence of male obesity-related secondary hypogonadism (MOSH) with emerging evidence on the role of testosterone therapy. We aim to provide an updated and practical approach towards its management. We did a comprehensive literature search across MEDLINE (via PubMed), Scopus, and Google Scholar databases using the keywords "MOSH" OR "Obesity-related hypogonadism" OR "Testosterone replacement therapy" OR "Selective estrogen receptor modulator" OR "SERM" OR "Guidelines on male hypogonadism" as well as a manual search of references within the articles. A narrative review based on available evidence, recommendations and their practical implications was done. Although weight loss is the ideal therapeutic strategy for patients with MOSH, achievement of significant weight reduction is usually difficult with lifestyle changes alone in real-world practice. Therefore, androgen administration is often necessary in the management of hypogonadism in patients with MOSH which also improves many other comorbidities related to obesity. However, there is conflicting evidence for the appropriate use of testosterone replacement therapy (TRT), and it can also be associated with complications. This evidence-based review updates the available evidence including the very recently published results of the TRAVERSE trial and provides comprehensive clinical practice pearls for the management of patients with MOSH. Before starting testosterone replacement in functional hypogonadism of obesity, it would be desirable to initiate lifestyle modification to ensure weight reduction. TRT should be coupled with the management of other comorbidities related to obesity in MOSH patients. Balancing the risks and benefits of TRT should be considered in every patient before and during long-term management.

The Role of Testosterone Therapy in Men's Health

Over the last 3 decades, there has been an increased interest in testosterone replacement therapy. This trend is a result of an aging population, endocrine disruptors in our foods and environment and rising obesity rates. In addition, there has been a surge in Men's Health clinics and online direct-to-consumer Web sites, making testosterone replacement therapy much more readily accessible. As more men seek to increase their testosterone levels, more long-term random control studies are needed to gain better insight into testosterone optimization to support the anecdotal observation commonly experienced in the practice setting.

Comparable bio-evaluation of curcumin and chitosan-encapsulated curcumin nanoparticles against the reprotoxic potential of fenpropathrin pyrethroid in rats: Genomic and morphometric prospectives

This study delves into the intricate exploration of potential toxic effects resulting from subchronic exposure to fenpropathrin (FNP) on the reproductive system of male SD rats. Adding to the novelty, our study undertakes a pioneering comparison of the effects of curcumin (CUR) and curcumin-encapsulated chitosan nanoparticles (CS.CUR.NPs) on these toxic effects. The study involved a cohort of sixty male SD rats (six groups): vehicle control, CUR, Cs.CUR.NPs, FNP, and two combination groups (FNP with CUR or Cs.CUR.NPs). The synthesized Cs.CUR.NPs nanoparticles underwent meticulous characterization using Fourier Infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The findings revealed that FNP caused oxidative stress, sperm abnormalities, reduced motility and sperm count FNP decreased serum LH, FSH, 17-β estradiol, and testosterone levels. FNP downregulated the mRNA expression of the spermatogenesis and steroidogenesis-related genes, While, downregulated hypothalamic KISS-1 and KISS-1r expression. Histopathological alterations were assessed and scored. Surprisingly, the treatment with CUR and Cs.CUR.NPs exhibited remarkable restorative effects on semen quality, sex hormone levels, antioxidant capacity, and mRNA expression of the targeted genes. Notably, Cs.CUR.NPs displayed superior properties when compared to CUR. Nevertheless, further research is imperative to evaluate their efficacy across various bodily tissues.

Approach to the Patient: The Evaluation and Management of Men ≥50 Years With Low Serum Testosterone Concentration

Although testosterone replacement in men with classic hypogonadism due to an identified pathology of the hypothalamic-pituitary-testicular axis is uncontroversial, the role of testosterone treatment for men with age-related declines in circulating testosterone is unclear. This is due to the lack of large, long-term testosterone therapy trials assessing definitive clinical endpoints. However, men ≥50 years of age, particularly those who have a body mass index >25 kg/m2 and multiple comorbidities, commonly present with clinical features of androgen deficiency and low serum testosterone concentrations. Clinicians are faced with the question whether to initiate testosterone therapy, a difficult dilemma that entails a benefit-risk analysis with limited evidence from clinical trials. Using a case scenario, we present a practical approach to the clinical assessment and management of such men.

Age-Related Hormones Changes and Its Impact on Health Status and Lifespan

The increase in life expectancy is accompanied with an increased consultation of age-related pathologies including endocrine disorders. Two main areas are focusing the attention of medical and social research in older population: the diagnosis and care of this heterogeneous population, and the interventional measures potentially useful to mitigate age-related functional declines and to increase health and quality of lifespan. Thus, better understanding the physiopathology of aging and establishing accurate diagnostic and personalized approaches are a priority and currently an unmet need of the medical community. The endocrine system plays a major role in survival and lifespan through regulating vital processes such as energy consumption and optimizing the stress response among others. The aim of this paper is to review the physiological evolution of the main hormonal functions in aging and its clinical translation to improve our approach to the aging patient.

The role of male hypogonadism, aging, and chronic diseases in characterizing adult and elderly men with erectile dysfunction: a cross-sectional study

BACKGROUND

Erectile function depends on a complex interaction between demographic, metabolic, vascular, hormonal, and psychological factors that trigger erectile dysfunction (ED). In the present study we carried out a cross-sectional study assessing the impact of non-communicable chronic diseases (NCDs), male hypogonadism, and demographic factors in characterizing men with ED. Four hundred thirty-three consecutive outpatients with ED were extracted from the electronic database from January 2017 to December 2019. The International Index of Erectile Function (IIEF) 5 score was used to diagnose ED and stratify its severity, standardized values of serum testosterone (10.5 nM/L) and luteinizing hormone (LH 9.4 IU/L) to diagnose and classify male hypogonadism and the Charlson Comorbidity Index (CCI) to weigh the role of each NCD on ED.

RESULTS

Forty-six percent of participants were eugonadal (EuG), 13% had organic hypogonadism (OrH), and the remaining 41% had functional hypogonadism (FuH). Hypogonadal men had a significantly lower IIEF 5 score (p < .0001) than EuG. FuH had a higher CCI than OrH and EuG (all p < .0001). In a multivariable model, only free T (FT) and Sex Hormone Binding Globulin (SHBG) showed a direct correlation with the IIEF 5 score (all p < .0001). Age and CCI had an inverse correlation with IIEF 5 score (all p < .0001).

CONCLUSION

Serum FT, SHBG, and CCI are the leading determinants of ED severity. Besides overt hypogonadism, a relevant burden of severe NTCDs in middle-aged or older adults features the patient's characteristics who will suffer from severe ED. Appropriate clinical approaches and, when necessary, treatments are required in these clusters of patients.

Obesity in Adults: Position Statement of Polish Association for the Study on Obesity, Polish Association of Endocrinology, Polish Association of Cardiodiabetology, Polish Psychiatric Association, Section of Metabolic and Bariatric Surgery of the Association of Polish Surgeons, and the College of Family Physicians in Poland

Obesity in adults and its complications are among the most important problems of public health. The search was conducted by using PubMed/MEDLINE, Cochrane Library, Science Direct, MEDLINE, and EBSCO databases from January 2010 to December 2022 for English language meta-analyses, systematic reviews, randomized clinical trials, and observational studies from all over the world. Six main topics were defined in the joint consensus statement of the Polish Association for the Study on Obesity, the Polish Association of Endocrinology, the Polish Association of Cardio-diabetology, the Polish Psychiatric Association, the Section of Metabolic and Bariatric Surgery of the Society of Polish Surgeons, and the College of Family Physicians in Poland: (1) the definition, causes and diagnosis of obesity; (2) treatment of obesity; (3) treatment of main complications of obesity; (4) bariatric surgery and its limitations; (5) the role of primary care in diagnostics and treatment of obesity and barriers; and (6) recommendations for general practitioners, regional authorities and the Ministry of Health. This statement outlines the role of an individual and the adequate approach to the treatment of obesity: overcoming obstacles in the treatment of obesity by primary health care. The approach to the treatment of obesity in patients with its most common complications is also discussed. Attention was drawn to the importance of interdisciplinary cooperation and considering the needs of patients in increasing the long-term effectiveness of obesity management.

Effects of treatment for diabetes mellitus on testosterone concentrations: A systematic review

BACKGROUND

Low testosterone levels are frequently present in men with obesity and insulin resistance. Currently available treatment options (testosterone replacement therapy or lifestyle changes) hold possible risks or are insufficient. Since low testosterone levels are closely related to obesity and type 2 diabetes, treatment modalities for these conditions could result into improvement of testosterone levels.

OBJECTIVES

To summarize the available evidence on the effects of traditional and recent treatment modalities for diabetes mellitus on testosterone levels and androgen-deficiency-related signs and symptoms.

MATERIALS AND METHODS

PubMed was searched from the year 2000 till present using MESH terms: "hypogonadism," "testosterone," "testosterone deficiency," "functional hypogonadism," and the different classes of medications. Studies with observational and experimental designs on humans that evaluated the effect of antidiabetic medications on gonadotropins and testosterone were eligible for inclusion.

RESULTS

Current available data show no or only limited improvement on testosterone levels with the classic antidiabetic drugs. Studies with GLP1-receptor analogues show beneficial effects on both body weight and testosterone levels in men with low testosterone levels and obesity with or without type 2 diabetes. However, data are limited to small and heterogeneous study groups and only few studies report data about impact on androgen-deficiency-related signs and symptoms.

DISCUSSION AND CONCLUSION

With the recent advances in the knowledge of the pathophysiological pathways in obesity, there is an enormous progress in the development of medications for obesity and type 2 diabetes. Newer incretin-based agents have a great potential for the treatment of functional hypogonadism due to obesity since they show promising weight reducing results. However, before the use of GLP1-receptor analogues can be suggested to treat functional hypogonadism, further studies are needed.

Adult- and late-onset male hypogonadism: the clinical practice guidelines of the Italian Society of Andrology and Sexual Medicine (SIAMS) and the Italian Society of Endocrinology (SIE)

PURPOSE

To provide the evidence-based recommendations on the role of testosterone (T) on age-related symptoms and signs remains.

METHODS

The Italian Society of Andrology and Sexual Medicine (SIAMS) and the and the Italian Society of Endocrinology (SIE) commissioned an expert task force to provide an updated guideline on adult-onset male hypogonadism. Derived recommendations were based on Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Clinical diagnosis of adult-onset hypogonadism should be based on a combination of clinical and biochemical parameters. Testosterone replacement therapy (TRT) should be offered to all symptomatic subjects with hypogonadism after the exclusion of possible contraindications. T gels and the long-acting injectable T are currently available preparations showing the best efficacy/safety profile. TRT can improve all aspects of sexual function, although its effect is limited in more complicated patients. Body composition (reducing fat mass and increasing lean mass) is improved after TRT, either in subjects with or without metabolic syndrome or type 2 diabetes. Conversely, the role of TRT in improving glycometabolic control is more conflicting. TRT can result in increasing bone mineral density, particularly at lumbar site, but no information on fracture risk is available. Limited data support the use of TRT for improving other outcomes, including mood frailty and mobility.

CONCLUSIONS

TRT can improve sexual function and body composition particularly in less complicated adult and in aging subjects with hypogonadism. When hypogonadism is adequately diagnosed, T appropriately prescribed and subjects correctly followed up, no short-term increased risk of adverse events is observed. Longer and larger studies are advisable to better clarify TRT long-term efficacy/safety profile.

Diagnosis of hypogonadism in ageing men

To make the diagnosis of hypogonadism in an ageing man, in absence of rare organic cause often referred to as functional or late onset hypogonadism (LOH), he should present with a clinical syndrome suggestive of androgen deficiency and have consistently low serum testosterone (T) levels. This does not differ from the diagnosis of any other form of hypogonadism. Particular to LOH diagnostic are uncertainties surrounding this entity: signs and symptoms of androgen deficiency (including sexual symptoms) are nonspecific in older men; clinical significance of only moderately low T levels is uncertain; comorbidity plays a substantial role with potential for reversibility; the place of T therapy in these men is debatable. This context demands for a pragmatic, but appropriately conservative approach to diagnosis. Evaluation should be stepwise with clinical evaluation, if suggestive for androgen deficiency, followed by measurement of a fasting morning serum T, if unequivocally low to be confirmed in a separate morning sample by a second low T or, if initial T borderline low or in presence of factors known to affect SHBG, by a low calculated free T level. All other (free) T results make hypogonadism an unlikely cause of the patient's symptoms. In the absence of consensus cut-off levels for total and free T in the published clinical guidelines for diagnosis of hypogonadism, it seems appropriate in the context of LOH to use stringent criteria indicating a convincingly low serum T. The approach to the diagnosis of LOH is not fundamentally different from that of other forms of hypogonadism but should put extra weight on prioritizing the shunning of overdiagnosis above the risk of underdiagnosis.

The role of testosterone in male sexual function

Sexual function, and testosterone (T) levels, progressively decline in aging men. Associated morbidities and metabolic disorders can accelerate the phenomenon. The specific contribution of low T to sexual function impairment in aging men has still not been completely clarified. Similarly, the role of T replacement therapy (TRT), as well as the combination of TRT with phosphodiesterase type 5 inhibitors (PDE5i) for patients with erectile dysfunction (ED), is still conflicting. Here we aim to summarize and critically discuss all available data supporting the contribution of low T to sexual impairment observed with aging as well as the possible role of TRT. Available data on men with sexual dysfunction show that reduced sexual desire is the most important correlate of male hypogonadism. Conversely, aging and associated morbidities substantially attenuate the relationship between ED and T. TRT is effective in improving sexual function in middle-aged and older subjects but its role is small and extremely variable. Lifestyle interventions can result in similar outcomes to those of TRT. In conclusion, it is our opinion that PDE5i along with lifestyle measures should be considered the first approach for treating ED even in subjects with milder T deficiency. When these interventions fail or are difficult to apply, TRT should be considered.

Ageing male (part I): Pathophysiology and diagnosis of functional hypogonadism

This narrative review summarizes key points of the pathogenesis and diagnosis of the ageing-related decline of testosterone (T) in men. The condition is commonly termed late-onset hypogonadism (LOH), but because it is more often caused by other factors than chronological ageing (obesity and other comorbidities), a more appropriate term is functional hypogonadism (FH). Unlike the classical organic hypogonadism, no anatomical or genetic aberrations are found in FH, and the suppression of T is milder. Moreover, FH can be reversible if the underlying cause (e.g. obesity, chronic disease) is removed/treated. Low serum total T in connection with more specific hypogonadism-associated symptoms (primarily sexual) form the basis of the diagnosis of FH. When T concentrations are borderline, the accuracy of diagnosis can be improved by assessment of free or calculated free T, especially when suppressed SHBG levels (usually related to obesity) are likely. Current data indicate that FH (low T and sexual symptoms) is not a common condition, and it is detectable in about 2% of community-dwelling men aged 40-80 years.

Diagnosis and Evaluation of Hypogonadism

A systematic approach to diagnose hypogonadism initially establishes the presence of symptoms/signs of testosterone deficiency, considers other potential causes of manifestations, and excludes conditions that transiently suppress testosterone. Hypogonadism is confirmed by measuring fasting serum total testosterone in the morning on at least 2 separate days, or free testosterone by equilibrium dialysis or calculated free testosterone in men with conditions that alter sex hormone-binding globulin or serum total testosterone near lower limit of normal. To guide management, further evaluation is performed to identify the specific cause of hypogonadism and whether it is potentially reversible or an irreversible pathologic disorder.

Society for Endocrinology guidelines for testosterone replacement therapy in male hypogonadism

Male hypogonadism (MH) is a common endocrine disorder. However, uncertainties and variations in its diagnosis and management exist. There are several current guidelines on testosterone replacement therapy that have been driven predominantly by single disciplines. The Society for Endocrinology commissioned this new guideline to provide all care providers with a multidisciplinary approach to treating patients with MH. This guideline has been compiled using expertise from endocrine (medical and nursing), primary care, clinical biochemistry, urology and reproductive medicine practices. These guidelines also provide a patient perspective to help clinicians best manage MH.

Increased risk of testosterone deficiency is associated with the systemic immune-inflammation index: a population-based cohort study

PURPOSE

This study aimed to explore the relationship between serum testosterone levels and systemic immune-inflammation index (SII).

METHODS

Complete SII and serum testosterone data of men over 20 years of age were retrieved from the 2011-2016 National Health and Nutrition Examination Survey to conduct a prevalence survey. To calculate SII, the platelet count was multiplied by the neutrophil-to-lymphocyte count ratio. Isotope dilution liquid chromatography and tandem mass spectrometry were employed to measure serum testosterone concentration. Testosterone deficiency (TD) was defined as a serum testosterone level ≤ 300ng/dl. Weighted proportions and multivariable regression analyses were used to analyze the association between SII and TD.

RESULTS

Overall, the data of 7389 participants were analyzed, The SII ranged from 1.53 - 6297.60. Of the participants, 28.42% had a low serum testosterone level (≤ 300 ng/dl). In the fully adjusted multivariable logistic model, the second quartile (OR: 1.27, p = 0.0737), the third quartile (OR: 1.43, p = 0.0090), and the fourth quartile (OR:1.48, p = 0.0042) of SII significantly increased the TD incidence rate, with the lowest quartile of the SII as a reference. For subgroup analysis, statistically significant associations were observed in participants aged 20-40, obese, non-hypertensive, and non-diabetic. The interaction test revealed no significant effect on this connection.

CONCLUSIONS

There was a positive relationship between a high SII and an increased prevalence of TD in a nationwide sample of adult men in the United States. Further prospective studies on a larger scale are warranted to confirm the causality between SII and TD.

Recommendations on the diagnosis, treatment and monitoring of testosterone deficiency in men

The relative proportional increase of the elderly population within many countries will become one of the most significant social transformations of the twenty-first century and, for the first time in history, persons aged 65 or above outnumbered children under five years of age globally. One in four persons living in Europe and Northern America will be aged 65 or over. One of the goals of ISSAM is to raise awareness of the special health needs of older men. Since a significant number of aging men will eventually become testosterone deficient, the Hypogonadism panel of ISSAM updates its guidelines.

Changes in white adipose tissue gene expression in a randomized control trial of dieting obese men with lowered serum testosterone alone or in combination with testosterone treatment

PURPOSE

The aim of this study was to determine early weight loss-associated changes in subcutaneous abdominal white adipose tissue (WAT) gene expression in obese men with lowered serum testosterone by RNA next-generation sequencing.

METHODS

Fourteen men, mean age (IQR) 51.6 years (43.4-54.5), BMI 38.3 kg/m² (34.6-40.8) and total testosterone 8.4 nmol/L (7.5-9.5) provided subcutaneous WAT samples at baseline and after 2 weeks of a very low energy diet.

RESULTS

Body weight loss was similar in participants receiving testosterone (n = 6), -5.27 kg [95% CI -6.17; -4.26], and placebo (n = 8), -4.57 kg [95% CI -6.10; -3.55], p = 0.86. In placebo-treated men, of the 14,410 genes expressed in subcutaneous WAT, four genes, Angiopoietin-like 4, Semaphorin 3 G, Neuropilin 2 and Angiopoietin 4, were upregulated (adjusted false discovery rate P < 0.05). In an exploratory analysis comparing men receiving testosterone and placebo, the most-upregulated gene in the testosterone group (exploratory p < 0.0005) was the neuropeptide y receptor 2.

CONCLUSIONS

In obese men, dieting is associated with upregulation of WAT-expressed Angiopoietin-like 4, a secreted protein that regulates lipid metabolism, Semaphorin 3 G, a proposed adipocyte differentiation factor and secreted adipokine, and its receptor Neuropilin 2, as well as Angiopoietin 4, a vascular integrity factor. In an exploratory analysis, testosterone was associated with the upregulation of neuropeptide y receptor 2, a receptor involved in appetite regulation. Further studies are needed to confirm these observations and their potential biological implications.

TRIAL REGISTRATION

clinicaltrials.gov, Identifier NCT01616732, Registration date: June 8, 2012.

Androgen Misuse and Abuse

Androgens are potent drugs requiring prescription for valid medical indications but are misused for invalid, unproven, or off-label reasons as well as being abused without prescription for illicit nonmedical application for performance or image enhancement. Following discovery and first clinical application of testosterone in the 1930s, commercialization of testosterone and synthetic androgens proliferated in the decades after World War II. It remains among the oldest marketed drugs in therapeutic use, yet after 8 decades of clinical use, the sole unequivocal indication for testosterone remains in replacement therapy for pathological hypogonadism, organic disorders of the male reproductive system. Nevertheless, wider claims assert unproven, unsafe, or implausible benefits for testosterone, mostly representing wishful thinking about rejuvenation. Over recent decades, this created an epidemic of testosterone misuse involving prescription as a revitalizing tonic for anti-aging, sexual dysfunction and/or obesity, where efficacy and safety remains unproven and doubtful. Androgen abuse originated during the Cold War as an epidemic of androgen doping among elite athletes for performance enhancement before the 1980s when it crossed over into the general community to become an endemic variant of drug abuse in sufficiently affluent communities that support an illicit drug industry geared to bodybuilding and aiming to create a hypermasculine body physique and image. This review focuses on the misuse of testosterone, defined as prescribing without valid clinical indications, and abuse of testosterone or synthetic androgens (androgen abuse), defined as the illicit use of androgens without prescription or valid indications, typically by athletes, bodybuilders and others for image-oriented, cosmetic, or occupational reasons.

Both comorbidity burden and low testosterone can explain symptoms and signs of testosterone deficiency in men consulting for sexual dysfunction

Low testosterone (T) is frequent in men with chronic illnesses. The clinical features of T deficiency (TD) overlap with those of chronic diseases. The aim of this study is to evaluate the relative contribution of chronic disease score (CDS) and low T to the presence of TD symptoms. A consecutive series of 3862 men (aged 52.1 ± 13.1 years) consulting for sexual dysfunction were studied. Several clinical and biochemical parameters were collected, including the structured interview, ANDROTEST, for the assessment of TD symptoms. Penile color Doppler ultrasound (PCDU) was also performed. Based on the medications taken, the CDS was calculated. For a subset of 1687 men, information on mortality was collected (follow-up of 4.3 ± 2.6 years). Higher CDS was associated with lower free and total T (TT) as well as with higher ANDROTEST score. When introducing CDS and TT in multivariable models adjusted for age, severe erectile dysfunction and impaired morning erections were associated with both CDS (odds ratio and 95% confidence interaval, OR [95% CI] = 1.25 [1.13; 1.37] and 1.38 [1.29; 1.48], respectively) and low TT (OR [95% CI] = 1.11 [1.00; 1.23] and 1.13 [1.06; 1.21], respectively). Similar results were obtained for PCDU parameters. Hypoactive sexual desire was associated with low TT (OR [95% CI] = 1.21 [1.13; 1.30]), whereas it was inversely related with CDS (OR [95% CI] = 0.91 [0.84; 0.97]). When considering mortality for major cardiovascular events, TT <8 nmol l⁻¹, but not CDS, was a significant predictor (hazard ratio [95% CI] = 5.57 [1.51; 20.63]). Chronic illnesses are associated with an overt TD. Both chronic diseases and low T can be involved in determining symptoms present in subjects complaining for sexual dysfunction. This should be considered in the diagnostic workup for TD.

Cardiovascular risk and testosterone - from subclinical atherosclerosis to lipoprotein function to heart failure

The cardiovascular (CV) benefit and safety of treating low testosterone conditions is a matter of debate. Although testosterone deficiency has been linked to a rise in major adverse CV events, most of the studies on testosterone replacement therapy were not designed to assess CV risk and thus excluded men with advanced heart failure or recent history of myocardial infarction or stroke. Besides considering observational, interventional and prospective studies, this review article evaluates the impact of testosterone on atherosclerosis process, including lipoprotein functionality, progression of carotid intima media thickness, inflammation, coagulation and thromboembolism, quantification of plaque volume and vascular calcification. Until adequately powered studies evaluating testosterone effects in hypogonadal men at increased CV risk are available (TRAVERSE trial), clinicians should ponder the use of testosterone in men with atherosclerotic cardiovascular disease and discuss benefit and harms with the patients.

Free testosterone and cardiometabolic parameters in men: comparison of algorithms

OBJECTIVE

Calculating the free testosterone level has gained increasing interest and different indirect algorithms have been suggested. The objective was to compare free androgen index (FAI), free testosterone estimated using the linear binding model (Vermeulen: cFTV) and the binding framework accounting for allosterically coupled SHBG monomers (Zakharov: cFTZ) in relation to cardiometabolic conditions.

DESIGN

A prospective cohort study including 5350 men, aged 30-70 years, participating in population-based surveys (MONICA I-III and Inter99) from 1982 to 2001 and followed until December 2012 with baseline and follow-up information on cardiometabolic parameters and vital status.

RESULTS

Using age-standardized hormone levels, FAI was higher among men with baseline cardiometabolic conditions, whereas cFTV and cFTZ levels were lower compared to men without these conditions as also seen for total testosterone. Men in highest quartiles of cFTV or cFTZ had lower risk of developing type 2 diabetes (cFTV: HR = 0.74 (0.49-1.10), cFTZ: HR = 0.59 (0.39-0.91)) than men in lowest quartile. In contrast, men with highest levels of FAI had a 74% (1.17-2.59) increased risk of developing type 2 diabetes compared to men in lowest quartile.

CONCLUSION

The association of estimated free testosterone and the studied outcomes differ depending on algorithm used. cFTV and cFTZ showed similar associations to baseline and long-term cardiometabolic parameters. In contrast, an empiric ratio, FAI, showed opposite associations to several of the examined parameters and may reflect limited clinical utility.

Glutathione (GSH) improves sperm quality and testicular morphology in streptozotocin-induced diabetic mice

Diabetes mellitus (DM) is known to cause reproductive impairment. In men, it has been linked to altered sperm quality and testicular damage. Oxidative stress (OS) plays a pivotal role in the development of DM complications. Glutathione (GSH) is a part of a nonenzymatic antioxidant defense system that protects lipid, protein, and nucleic acids from oxidative damage. However, the protective effects of exogenous GSH on the male reproductive system have not been comprehensively examined. This study determined the impact of GSH supplementation in ameliorating the adverse effect of type 1 DM on sperm quality and the seminiferous tubules of diabetic C57BL/6NTac mice. GSH at the doses of 15 mg kg⁻¹ and 30 mg kg⁻¹ was given intraperitoneally to mice weekly for 6 consecutive weeks. The mice were then weighed, euthanized, and had their reproductive organs excised. The diabetic (D Group) showed significant impairment of sperm quality and testicular histology compared with the nondiabetic (ND Group). Diameters of the seminiferous lumen in diabetic mice treated with 15 mg kg⁻¹ GSH (DGSH15) were decreased compared with the D Group. Sperm motility was also significantly increased in the DGSH15 Group. Improvement in testicular morphology might be an early indication of the protective roles played by the exogenous GSH in protecting sperm quality from effects of untreated type 1 DM or diabetic complications. Further investigation using different doses and different routes of GSH is necessary to confirm this suggestion.

Diet during early life defines testicular lipid content and sperm quality in adulthood

Childhood obesity is a serious concern associated with ill health later in life. Emerging data suggest that obesity has long-term adverse effects upon male sexual and reproductive health, but few studies have addressed this issue. We hypothesized that exposure to high-fat diet during early life alters testicular lipid content and metabolism, leading to permanent damage to sperm parameters. After weaning (day 21 after birth), 36 male mice were randomly divided into three groups and fed with a different diet regimen for 200 days: a standard chow diet (CTRL), a high-fat diet (HFD) (carbohydrate: 35.7%, protein: 20.5%, and fat: 36.0%), and a high-fat diet for 60 days, then replaced by standard chow (HFD_t). Biometric and metabolic data were monitored. Animals were then euthanized, and tissues were collected. Epididymal sperm parameters and endocrine parameters were evaluated. Testicular metabolites were extracted and characterized by 1H-NMR and GC-MS. Testicular mitochondrial and antioxidant activity were evaluated. Our results show that mice fed with a high-fat diet, even if only until early adulthood, had lower sperm viability and motility, and higher incidence of head and tail defects. Although diet reversion with weight loss during adulthood prevents the progression of metabolic syndrome, testicular content in fatty acids is irreversibly affected. Excessive fat intake promoted an overaccumulation of proinflammatory n-6 polyunsaturated fatty acids in the testis, which is strongly correlated with negative effects upon sperm quality. Therefore, the adoption of high-fat diets during early life correlates with irreversible changes in testicular lipid content and metabolism, which are related to permanent damage to sperm quality later in life.

Decreased testosterone secretion index and free testosterone level with multiple symptoms for late-onset hypogonadism identification: a nationwide multicenter study with 5980 aging males in China

Late-onset hypogonadism (LOH) is a syndrome in middle-aged and elderly men caused by age-related testosterone deficiency. Age-related change of total testosterone (TT) of Asian males is different from Caucasian population, suggesting difference for LOH identification in Asians. A nationwide cross-sectional study involving six centers in China was conducted. Totally 6296 men aged 40-79 were recruited. After exclusions 5980 men were left for analyses. The serum TT level, was neither decreased with aging nor correlated with most hypogonadal symptoms. Instead, ten hypogonadal symptoms were found to be significantly correlated with free testosterone and testosterone secretion index, thus were chosen to form a concise scale. Further analysis identified a level of free testosterone <210 pmol/L, testosterone secretion index <1.8, and the concise scale score ≧17 could be diagnosed as having significantly aggravated LOH. This study developed an evidence-based criteria for LOH identification in Chinese population and may be adopted in other Asians. It includes the impaired testosterone secretion ability and deficiency of bioavailable testosterone, which should be the main cause in LOH pathogenesis despite normal TT levels, as well as correlated multiple hypogonadal symptoms. Our results may guide the LOH treatment to increase testicular function of testosterone secretion and bioavailable testosterone.

Lifestyle, metabolic disorders and male hypogonadism - A one-way ticket?

Hypogonadism is more frequent among men with common metabolic diseases, notably obesity and type 2 diabetes. Indeed, endocrine disruption caused by metabolic diseases can trigger the onset of hypogonadism, although the underlying molecular mechanisms are not entirely understood. Metabolic diseases are closely related to unhealthy lifestyle choices, such as dietary habits and sedentarism. Therefore, hypogonadism is part of a pathological triad gathering unhealthy lifestyle, metabolic disease and genetic background. Additionally, hypogonadism harbors the potential to aggravate underlying metabolic disorders, further sustaining the mechanisms leading to disease. To what extent does lifestyle intervention in men suffering from these metabolic disorders can prevent, improve or reverse hypogonadism, is still controversial. Moreover, recent evidence suggests that the metabolic status of the father is related to the risk of inter and transgenerational inheritance of hypogonadism. In this review, we will address the proposed mechanisms of disease, as well as currently available interventions for hypogonadism.

European Academy of Andrology (EAA) guidelines on investigation, treatment and monitoring of functional hypogonadism in males: Endorsing organization: European Society of Endocrinology

BACKGROUND

Evidence regarding functional hypogonadism, previously referred to as 'late-onset' hypogonadism, has increased substantially during the last 10 year.

OBJECTIVE

To update the European Academy of Andrology (EAA) guidelines on functional hypogonadism.

METHODS

Expert group of academicians appointed by the EAA generated a series of consensus recommendations according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

RESULTS

The diagnosis of functional hypogonadism should be based on both the presence of clinical symptoms supported by repeatedly low morning fasting serum total testosterone (T) measured with a well-validated assay, after exclusion of organic causes of hypogonadism. Lifestyle changes and weight reduction should be the first approach in all overweight and obese men. Whenever possible, withdrawal/modification of drugs potentially interfering with T production should be advised. Testosterone replacement therapy (TRT) is contraindicated in men with untreated prostate or breast cancer, as well as severe heart failure. Severe low urinary tract symptoms and haematocrit >48%-50% represent relative contraindications for TRT. Prostate-specific antigen and digital rectal examination of the prostate should be undertaken in men >40 years of age before initiating TRT to exclude occult prostate cancer. Transdermal T should be preferred for initiation of TRT, whereas gonadotrophin therapy is only recommended when fertility is desired in men with secondary hypogonadism. TRT is able to improve sexual function in hypogonadal men. Other potential positive outcomes of TRT remain uncertain and controversial.

CONCLUSION

TRT can reliably improve global sexual function in men with hypogonadism in the short term. Long-term clinical benefits, and safety of TRT in functional hypogonadism, remain to be fully documented. Clinicians should therefore explicitly discuss the uncertainties and benefits of TRT and engage them in shared management decision-making.

Hypogonadism, Type-2 Diabetes Mellitus, and Bone Health: A Narrative Review

One of the complications from chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men is the high prevalence of hypogonadotropic hypogonadism (HH). Both T2DM and hypogonadism are associated with impaired bone health and increased fracture risk but whether the combination results in even worse bone disease than either one alone is not well-studied. It is possible that having both conditions predisposes men to an even greater risk for fracture than either one alone. Given the common occurrence of HH or hypogonadism in general in T2DM, a significant number of men could be at risk. To date, there is very little information on the bone health men with both hypogonadism and T2DM. Insulin resistance, which is the primary defect in T2DM, is associated with low testosterone (T) levels in men and may play a role in the bidirectional relationship between these two conditions, which together may portend a worse outcome for bone. The present manuscript aims to review the available evidences on the effect of the combination of hypogonadism and T2DM on bone health and metabolic profile, highlights the possible metabolic role of the skeleton, and examines the pathways involved in the interplay between bone, insulin resistance, and gonadal steroids.

Ramifications of variability in sex hormone-binding globulin measurement by different immunoassays on the calculation of free testosterone

Objective

Sex hormone-binding globulin (SHBG) is a glycoprotein which binds hormones such as testosterone. Around 97% of circulating testosterone is bound to SHBG or albumin and is therefore biologically unavailable; 2–3% of testosterone is free. Free testosterone is very technically challenging to quantify; in order to circumvent this problem, equations using testosterone and SHBG are used to estimate free testosterone. We decided to determine the effect of using different SHBG immunoassays on calculated free testosterone results.

Design

Anonymized surplus serum samples were analysed for SHBG on four different immunoassay platforms (Abbott Architect, Roche, Beckman and Siemens). The SHBG results were used to generate a Vermeulen calculated free testosterone.

Results

Beckman Access and Siemens Centaur both gave results close to the overall mean. Roche gave the highest SHBG concentrations with Abbott Architect producing the lowest results. Abbott Architect gave the highest calculated free testosterone results, followed by Beckman. Roche gave the lowest results. Sixty-five per cent of male samples had low calculated free testosterone and 27.5% of the females had high calculated free testosterone using the SHBG from the Abbott assay compared with 69% low male calculated free testosterone and 20% high female calculated free testosterone with the Roche assay.

Conclusion

Our results have shown significant differences in SHBG results produced by different analysers and subsequently the calculated free testosterone, which may affect result interpretation if method-specific reference ranges for calculated free testosterone are not used. Care should be taken to ensure reference ranges are appropriate for the analyser used to avoid misdiagnosis of hypo or hyperandrogenism, and ensure patients get the most appropriate treatment.

Metabolically healthy and unhealthy obesity in erectile dysfunction and male infertility

Introduction: Metabolically unhealthy obesity (MUHO) is the most important preventable cardiovascular (CV) risk factor. Recently, the significance of metabolically healthy obesity (MHO) as a CV risk factor has raised increasing interest. MUHO is a known risk factor for erectile dysfunction (ED); however, the effect of MHO on ED has barely been investigated. This review aims at summarizing the evidence supporting the relation of MUHO and MHO to male sexual functioning and fertility. Areas covered: An extensive Medline search on obesity and ED or male infertility was conducted to summarize the role of MUHO or MHO on male sexual dysfunction and infertility. Expert opinion: Longitudinal studies have demonstrated that MHO causes vascular damage, which is consistent with the impairment in penile blood flows found in ED subjects. In this population, MHO is a predictor of CV events. The relationship between male infertility and MUHO is currently debated and data on MHO are almost completely lacking. The only available study did not find an association between obesity classes and semen parameters. Although the andrological correlates of MHO must be better assessed, in the current state, evidence suggests that MHO does not represent a benign condition and measures for improving lifestyle are mandatory.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Obesity and male hypogonadism: Tales of a vicious cycle

Obesity prevalence, particularly in children and young adults, is perilously increasing worldwide foreseeing serious negative health impacts in the future to come. Obesity is linked to impaired male gonadal function and is currently a major cause of hypogonadism. Besides signs and symptoms directly derived from decreased circulating testosterone levels, males with obesity also present poor fertility outcomes, further evidencing the parallelism between obesity and male reproductive function. In addition, males with androgen deficiency also exhibit increased fat accumulation and reduced muscle and mineral bone mass. Thus, compelling evidence highlights a vicious cycle where male hypogonadism can lead to increased adiposity, while obesity can be a cause for male hypogonadism. On the opposite direction, sustained weight loss can attain amelioration of male gonadal function. In this scenario, a thorough evaluation of gonadal function in men with obesity is crucial to dissect the causes from the consequences in order to target clinical interventions towards maximized improvement of reproductive health. This review will address the causes and consequences of the bidirectional relationship between obesity and hypogonadism, highlighting the implicit male reproductive repercussions.

Paediatric and adult-onset male hypogonadism

The hypothalamic-pituitary-gonadal axis is of relevance in many processes related to the development, maturation and ageing of the male. Through this axis, a cascade of coordinated activities is carried out leading to sustained testicular endocrine function, with gonadal testosterone production, as well as exocrine function, with spermatogenesis. Conditions impairing the hypothalamic-pituitary-gonadal axis during paediatric or pubertal life may result in delayed puberty. Late-onset hypogonadism is a clinical condition in the ageing male combining low concentrations of circulating testosterone and specific symptoms associated with impaired hormone production. Testosterone therapy for congenital forms of hypogonadism must be lifelong, whereas testosterone treatment of late-onset hypogonadism remains a matter of debate because of unclear indications for replacement, uncertain efficacy and potential risks. This Primer focuses on a reappraisal of the physiological role of testosterone, with emphasis on the critical interpretation of the hypogonadal conditions throughout the lifespan of the male individual, with the exception of hypogonadal states resulting from congenital disorders of sex development.

Clinical practice update on testosterone therapy for male hypogonadism: Contrasting perspectives to optimize care

US Endocrine Society (ES) published a clinical practice guideline on testosterone therapy in men with hypogonadism, and Endocrine Society of Australia (ESA) a position statement on management of male hypogonadism. Both emphasize the importance of diagnosing men who are androgen deficient due to organic (classical or pathological) hypogonadism arising from disorders of the hypothalamus, pituitary or testes, who assuredly benefit from testosterone therapy. Both recognize that men with an intact gonadal axis may have low testosterone concentrations, for instance older men or men with obesity or other medical comorbidities. ES guidelines classify such symptomatic men as having organic (advanced age) or functional (obesity, medical comorbidities) hypogonadism, giving an option for testosterone therapy as a shared decision between clinicians and individual patients. ESA did not recommend testosterone therapy in these men. ES offers a reference range for total testosterone established in young men, while ESA cites age-standardized reference ranges. ES recommends using free testosterone as well as total testosterone to identify men with hypogonadism in conditions where sex hormone-binding globulin (SHBG) is altered, or when total testosterone is borderline. ESA recommends confirmatory biochemical testing with total testosterone, recognizing that this may be lower than expected if SHBG concentrations are low. Both emphasize the importance of identifying pre-existing prostate and cardiovascular disease prior to initiating testosterone therapy, with ES providing specific recommendations for PSA measurement, deferring testosterone therapy after major cardiovascular events and indications for pituitary imaging. These contrasting approaches highlight gaps in the evidence base where individualized patient management is required.

Low Testosterone in Adolescents & Young Adults

Male hypogonadism, the clinical syndrome with variable symptoms associated with gonadal dysfunction, can affect men of all ages. In older males, physiologic changes of the aging testis, account for the majority of decreased testosterone levels in this population. For younger males and adolescents, the etiology of hypogonadism is commonly due to congenital or acquired conditions that disrupt the testis production of testosterone or signaling from the hypothalamic-pituitary-gonadal axis. Diagnosis of hypogonadism in younger males can be a challenge, as symptoms such as decreased libido or erectile dysfunction, common in the older men, are not usually present, and young men instead commonly complain of low energy. While an underlying congenital cause should always be considered in young men with hypogonadism, acquired conditions such as obesity, diabetes, anabolic steroid or illicit drug use have all been associated with low testosterone levels. Outside of modifying identifiable risk factors for hypogonadism, pharmacologic testosterone therapy can also lead to therapeutic dilemmas in young men who desire paternity. Topical or injectable administration of testosterone, through negative feedback on the hypothalamus and pituitary, can decrease spermatogenesis, posing an infertility risk. Other agents that can replace testosterone or increase the body's natural production of testosterone without decreasing spermatogenesis are preferred, such as intranasal testosterone, selective estrogen modulators, aromatase inhibitors or human-chorionic gonadotrophin, often used in combination. Clinicians must maintain a high level of suspicion to properly diagnose young men with hypogonadism and tailor treatment based on both the underlying etiology and fertility goals.

Free testosterone correlated with erectile dysfunction severity among young men with normal total testosterone

Erectile dysfunction (ED) due to androgen deficiency is rare in the young population. We retrospectively evaluated in this study men aged 18-40 years presenting with ED from 2015 to 2017. The International Index of Erectile Function-5 (IIEF-5) and Erection Hardness Grade Scores (EHGS) were used to assess erectile function. Total testosterone (TT), sex hormone-binding globulin (SHBG), lipid profile, and glycometabolic indicators were tested in fasting blood sample. TT and SHBG were detected by electrochemiluminescence immunoassay, and free (FT) and bio-available testosterone (BT) were calculated from a validated formula. Linear regression was used to analyze the data. In total, 140 cases (30.56 ± 4.81 years) with a mean TT levels of 6.15 ± 2.17 ng/ml were enrolled. Decreased levels of FT were associated with lower IIEF-5 scores(β = 0.176, P = 0.048) and EHGS (β = 0.198, P = 0.026) after adjustment for age, body mass index (BMI), smoking, comorbidities, high-sensitive C-reactive protein (hsCRP), uric acid, fructosamine, and quantitative insulin sensitivity check index (QUICKI). TT was only associated with EHGS in the crude model (β = 0.177, P = 0.037) and some single factor adjustment models, whereas BT and SHBG were not related with erectile function in any model. Low FT level, even in the presence of normal TT, is associated with ED severity in young men. FT levels should be screened in ED patient even with normal total testosterone.