The practical management of testosterone deficiency in men

Association between life's essential 8 and testosterone deficiency in US men: findings from national health and nutrition examination survey (NHANES) 2011-2016

Background

Testosterone deficiency (TD) is closely associated with cardiovascular diseases (CVD). We intended to explore the association of Life's Essential 8 (LE8), the recently updated measurement of cardiovascular health, with the prevalence of TD among US male adults.

Methods

The population-based cross-sectional study selected male adults aged 20 years or older from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016. According to the American Heart Association definitions, the LE8 score was measured on a scale of 0-100, and divided into health behavior and health factor scores, simultaneously. Furthermore, these scores were categorized into low (0-49), moderate (50-79), and high (80-100) classifications. TD is defined as a total testosterone level below 300ng/dL. Correlations were investigated by weighted multivariable logistic regression, and the robustness of the results were verified by subgroup analysis.

Results

A total of 4971 male adults with an average age of 47.46 ± 0.41 years were eligible for the final analyses, of whom 1372 were determined to have TD. The weighted mean LE8 score of the study population was 68.11 ± 0.41. After fully adjusting potential confounders, higher LE8 scores were significantly associated with low risk of TD (odd ratio [OR] for each 10-point increase, 0.79; 95% CI, 0.71-0.88) in a linear dose-response relationship. Similar patterns were also identified in the association of health factor scores with TD (OR for each 10-point increase, 0.74; 95% CI, 0.66-0.83). These results persisted when LE8 and health factor scores was categorized into low, moderate, and high groups. The inversed association of LE8 classifications and TD remained statistically significant among older, obese, and men without CVD.

Conclusions

LE8 and its health factor subscales scores were negatively associated with the presence of TD in linear fashions. Promoting adherence to optimal cardiovascular health levels may be advantageous to alleviate the burden of TD.

Association between weight-adjusted waist index and testosterone deficiency in adult American men: findings from the national health and nutrition examination survey 2013-2016

BACKGROUND

Testosterone deficiency (TD) and obesity are globally recognized health concerns, with a bidirectional causal relationship between them. And a newly discovered obesity indicator, the Weight-Adjusted-Waist Index (WWI), has been proposed, demonstrating superior adiposity identification capability compared to traditional body mass index (BMI) and waist circumference (WC) indicators. Therefore, we present the inaugural investigation into the associations of WWI with total testosterone levels and the risk of TD.

METHODS

Data restricted to the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2016 were analyzed. Only males aged > 20 years who completed body measures and underwent serum sex hormone testing were potentially eligible for analysis. Weighted multivariable linear regression and logistic regression analyses were employed to investigate the relationships between WWI and total testosterone levels, and the risk of TD, respectively. Smooth curve fittings and weighted generalized additive model (GAM) regression were conducted to examine the linear relationship among them. Additionally, subgroup analyses with interaction tests were performed to assess the stability of the results.

RESULTS

Finally, a total of 4099 participants with complete data on testosterone and WWI were included in the formal analysis. The mean age of study participants was 46.74 ± 0.35 years with a TD prevalence of 25.54%. After adjusting all potential confounders, the continuous WWI displayed a negative linear relationship with total testosterone levels (β=-61.41, 95%CI: -72.53, -50.29, P < 0.0001) and a positive linear relationship with risk of TD (OR = 1.88, 95%CI: 1.47, 2.39, P < 0.0001). When WWI was transformed into quartiles as a categorical variable, participants in Q4 exhibited lower total testosterone levels (β=-115.4, 95%CI: -142.34, -88.45, P < 0.0001) and a higher risk of TD (OR = 3.38, 95% CI: 2.10, 5.44, P < 0.001). These associations remained stable in subgroup analyses without significant interaction (all P for interaction > 0.05).

CONCLUSIONS

This investigation firstly unveiled a negative linear association between WWI and total testosterone levels, coupled with a positive linear relationship with the prevalence of TD in U.S. male adults aged 20 years and older. Further studies are needed to validate the potential utility of WWI for the early identification and timely intervention of TD.

Association between life's essential 8 and male biochemical androgen deficiency: evidence from NHANES 2013-2016

Purpose

To evaluate the association of Life's Essential 8 (LE8) and its subscales with male biochemical androgen deficiency (MBAD) and total testosterone based on the data from the national health and nutrition examination survey (NHANES) database.

Methods

Data of males aged 20 years or older from NHANES of 2013-2016 were extracted. LE8 score was calculated based on American Heart Association definitions. Total testosterone (TT) values were measured in NHANES using precise isotope dilution liquid chromatography. MBAD was defined as serum TT of <300 ng/dL. Univariate and multivariable analyses were conducted. Propensity score matching (PSM) and weighted regression after matching were added as sensitivity analyses. The generalized additive model, smooth curve fitting, and the recursive algorithm were used to determine the potential inflection points. Piecewise regression models with log-likelihood ratio test were used to quantify nonlinear effects.

Results

A total of 3094 participants who were males and aged 20 years or above were included. Out of them, 805 males were diagnosed with MBAD. After adjusting the confounders in the multivariable model, LE8 was independently associated with MBAD (OR 0.96, P < 0.001) and TT (β 2.7, P < 0.001). The association remained robust even after PSM. The non-linear relationship of LE8 behaviors score with MBAD and TT was revealed.

Conclusion

LE8 was an independent protective factor of MBAD and a feasible approach to promote male endocrine sexual function.

Association between weight-adjusted waist index and serum total testosterone in males aged 6-19 years in the United States: Data from NHANES 2013-2016

Objective

This study aimed to estimate the association between weight-adjusted waist index and serum total testosterone (sTT) in males aged 6-19 years in the United States.

Methods

A cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) 2013-2016. sTT was considered as the response variable, and weight-adjusted waist circumference index (WWI) as the independent variable. Multiple linear regression was performed to estimate the association between the two variables, and subgroup analysis was performed to identify sensitive cohorts. Smoothing curve fitting and threshold effects analysis was carried out to assess possible nonlinear relationships between WWI and sTT.

Results

The study included 4207 participants. The mean value of sTT (117.93 ng/dl) was used as the grouping basis, with 1066 participants having serum total testosterone levels above the mean. A negative association was observed between WWI and sTT [beta coefficient (β) = -72.50, 95% confidence interval (CI): -79.45, -65.55], which decreased as WWI increased (P for trend<0.05). Subgroup analysis indicated a stronger negative correlation in late adolescent (16-19 years) males (β = -128.94, 95% CI: -146.75, -111.13). The smoothing curve fit analysis revealed a U-shaped curve relationship for the negative correlation between WWI and sTT. Threshold effect analysis suggested a significant change when WWI exceeded 10.09 (β = -15.82, 95% CI: -24.11, -7.54), and stepwise threshold effect analysis indicated that this negative correlation became less stable when WWI exceeded 11.45 (β = -0.80, 95% CI: -9.15, 7.56).

Conclusions

Participants with higher WWI exhibited lower total testosterone levels, and a negative association was found between WWI and total testosterone, particularly in late adolescent males aged 16-19 years. Among males aged 6-19 years, caution should be exercised regarding the risk of lower testosterone levels associated with elevated WWI, particularly when WWI is below 10.09.

Comparison of Intratesticular Testosterone between Men Receiving Nasal, Intramuscular, and Subcutaneous Pellet Testosterone Therapy: Evaluation of Data from Two Single-Center Randomized Clinical Trials

PURPOSE

Testosterone replacement therapy (TRT) can potentially cause decreased spermatogenesis and subsequent infertility. Recent studies have suggested that 17-hydroxyprogesterone (17-OHP) is a reliable surrogate for intratesticular testosterone (ITT) that is essential for spermatogenesis. We evaluated data from two ongoing open-label, randomized, two-arm clinical trials amongst different treatment preparations (Trial I) subcutaneous testosterone pellets (TP) and (Trial II) intranasal testosterone (NT) or intramuscular testosterone cypionate (TC).

MATERIALS AND METHODS

Seventy-five symptomatic hypogonadal men (2 serum testosterone <300 ng/dL) were randomized into open label randomized clinical trials. Eligible subjects received 800 mg TP, 11 mg TID NT or 200 mg ×2 weeks TC. 17-OHP and Serum testosterone were evaluated at baseline and follow-up. The primary outcome was changes in 17-OHP. Secondary outcome was changes in serum testosterone. Data was analyzed by two-sample and single-sample t-tests, and determination of equal or unequal variances was computed using F-tests.

RESULTS

Median participant age was 45 years old, with overall baseline 17-OHP of 46 and serum testosterone of 223.5 ng/dL. 17-OHP significantly decreased in subjects prescribed long-acting TP or TC. The 4-month change in 17-OHP in the NT group (-33.3% from baseline) was less than the change seen in TC (-65.3% from baseline) or TP (-44% from baseline) (p=0.005). All testosterone formulations increased serum testosterone levels at follow-up, with the largest increase seen in TC (+157.6%), followed by NT (+114.3%) and TP (+79.6%) (p=0.005).

CONCLUSIONS

Short-acting nasal testosterone appear to have no impact on serum 17-OHP especially in comparison to long-acting testosterone formulations. All modalities saw significant increases in serum testosterone levels at follow-up. NT and other short acting testosterone formulations may better preserve ITT and be beneficial for hypogonadal men seeking to maintain fertility potential while on TRT.

Update on canine anorchia: A review

Abnormalities of the external genitals are an important issue in dog breeding because of the unfavourable qualities and characteristics of breeds, resulting in consistent economic losses. Despite their significance, little scientific attention has been given to these problems. Although there are several reviews on cryptorchidism in dogs, none have described anorchia. Testicular agenesis is a rare reproductive disorder with a congenital origin. Moreover, no author has described the diagnostic procedure for making a definitive diagnosis of anorchia in dogs. It is important to have a well-structured diagnostic scheme to help practical veterinarians make a confirmatory diagnosis. This review article aims to provide an update on canine anorchia diagnosis based on the poor research studies published in recent years. We have also contributed to the pathogenesis of this disorder using human medicine studies. Finally, the review includes therapeutic hypotheses that can be expanded in future studies.

The association between sex hormones and periodontitis among American adults: A cross-sectional study

INTRODUCTION

After adulthood, as a person grows older, the secretion of sex hormones in the body gradually decreases, and the risk of periodontitis increases. But the relationship between sex hormones and periodontitis is still controversial.

METHODS

We investigated the association between sex hormones and periodontitis among Americans over 30 years old. 4,877 participants containing 3,222 males and 1,655 postmenopausal females who had had periodontal examination and detailed available sex hormone levels, were included in our analysis from the 2009-2014 National Health and Nutrition Examination Surveys cycles. We applied multivariate linear regression models to estimate the connection between sex hormones and periodontitis after converting sex hormones into categorical variables through tertile. Additionally, to ensure the stability of the analysis results, we carried out a trend test, subgroup analysis, and interaction test.

RESULTS

After fully adjusting the covariates, estradiol levels were not associated with periodontitis in both males and females with a P for trend = 0.064 and 0.064, respectively. For males, we found that sex hormone-binding globulin was positively associated with periodontitis (tertile3 vs tertile1: OR=1.63, 95% CI=1.17-2.28, p = 0.004, P for trend = 0.005). Congruously, free testosterone (tertile3 vs tertile1: OR=0.60, 95% CI=0.43-0.84, p = 0.003), bioavailable testosterone (tertile3 vs tertile1: OR=0.51, 95% CI=0.36-0.71, p < 0.001), and free androgen index (tertile3 vs tertile1: OR=0.53, 95% CI=0.37-0.75, p < 0.001) was found to be negatively associated with periodontitis. Moreover, subgroup analysis of age found a closer relationship between sex hormones and periodontitis in those younger than 50 years.

CONCLUSION

Our research suggested that males with lower bioavailable testosterone levels affected by sex hormone-binding globulin were at a higher risk of periodontitis. Meanwhile, estradiol levels were not associated with periodontitis in postmenopausal women.

Association between snoring frequency and male serum testosterone: Findings from the 2015-2016 National Health and Nutrition Examination Survey

BACKGROUND

This study aimed to assess the association between snoring frequency and male serum testosterone levels.

METHODS

We analyzed data from the 2015 to 2016 National Health and Nutrition Examination Survey. Snoring frequency was relied on self-report, and was divided into never, rarely (1-2 nights a week), occasionally (3-4 nights a week), or frequently (5 or more nights a week) groups. Multivariable analysis controlling for age, race, waist circumference, total cholesterol, diabetes, and hypertension was used to evaluate the association between snoring frequency and male serum testosterone. Furthermore, we performed the subgroup analyses stratified by age and waist circumference.

RESULTS

Our analysis included 1900 participants. In the fully adjusted model, only frequent snoring was inversely associated with male serum testosterone (β -0.053, 95% CI -0.101 to -0.006, P = 0.028); According to the subgroup analysis stratified by age, only in 40-59 years group, frequent snoring was inversely associated with male serum testosterone in the fully adjusted model (β -0.113, 95% CI -0.196 to -0.031, P = 0.007). As for the subgroup analysis stratified by waist circumference, our results showed only in the waist circumference ≥102 cm group (abdominal obesity), frequent snoring was inversely associated with male serum testosterone (β -0.133, 95% CI -0.216 to -0.05, P = 0.002).

CONCLUSIONS

Frequent snoring (5 or more nights a week) is inversely associated with male serum testosterone levels, especially in those aged 40-59 years and those with abdominal obesity.

Sex Differences in the Effect of Vitamin D on Fatigue in Palliative Cancer Care-A Post Hoc Analysis of the Randomized, Controlled Trial 'Palliative-D'

Simple Summary

Previous studies have shown an association between low 25-hydroxyvitamin D levels and fatigue in cancer patients. In the recently published randomized, placebo-controlled, double-blind, multicenter trial ‘Palliative-D’, the correction of vitamin D deficiency reduced opioid use and fatigue in vitamin-D-deficient cancer patients admitted to palliative care. No subgroup analyses in women and men were made in the Palliative-D study. This post hoc analysis suggests that the positive effect of vitamin D supplementation on cancer-related fatigue may be more pronounced in men than in women. The vitamin-D-induced effect on fatigue could not be explained by reduced opioid doses among the vitamin-D-treated patients. Future studies focused on analyzing sex differences in the effect of vitamin D in palliative cancer care is needed before firm conclusions can be drawn.

Abstract

In the randomized, placebo-controlled, double-blind trial ‘Palliative-D’, vitamin D treatment of 4000 IE/day for 12 weeks reduced opioid use and fatigue in vitamin-D-deficient cancer patients. In screening data from this trial, lower levels of vitamin D were associated with more fatigue in men but not in women. The aim of the present study was to investigate possible sex differences in the effect of vitamin D in patients with advanced cancer, with a specific focus on fatigue. A post hoc analysis of sex differences in patients completing the Palliative-D study (n = 150) was performed. Fatigue assessed with the Edmonton Symptom Assessment Scale (ESAS) was reduced in vitamin-D-treated men; −1.50 ESAS points (95%CI −2.57 to −0.43; p = 0.007) but not in women; −0.75 (95%CI −1.85 to 0.36; p = 0.18). Fatigue measured with EORTC QLQ-C15-PAL had a borderline significant effect in men (−0.33 (95%CI −0.67 to 0.03; p = 0.05)) but not in women (p = 0.55). The effect on fatigue measured with ESAS in men remained the same after adjustment for opioid doses (p = 0.01). In conclusion, the positive effect of the correction of vitamin D deficiency on fatigue may be more pronounced in men than in women. However, studies focused on analyzing sex differences in this context must be performed before firm conclusions can be drawn.

3β-Hydroxysteroid dehydrogenase expressed by gut microbes degrades testosterone and is linked to depression in males

Testosterone deficiency can lead to depressive symptoms in humans; however, the causes of this deficiency are incompletely understood. Here, we isolated Mycobacterium neoaurum from the fecal samples of testosterone-deficient patients with depression and showed that this strain could degrade testosterone in vitro. Furthermore, gavaging rats with M. neoaurum reduced their serum and brain testosterone levels and induced depression-like behaviors. We identified the gene encoding 3β-hydroxysteroid dehydrogenase (3β-HSD) as the enzyme causing testosterone degradation. Introducing 3β-HSD into Escherichia coli enhanced its ability to degrade testosterone. Gavaging rats with 3β-HSD-producing E. coli reduced their serum and brain testosterone levels and caused depression-like behaviors. Finally, compared with 16.67% of participants without depression, 42.99% (46/107) of the fecal samples of patients with depression harbored 3β-HSD, and 60.87% (28/46) of these fecal samples expressed 3β-HSD. These results suggest that 3β-HSD expressed by gut microbes may be associated with depressive symptoms due to testosterone degradation.

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.

Correction of Androgen Deficiency in Men with Type 2 Diabetes

BACKGROUND

In men with low levels of testosterone in the blood, it is believed that the symptoms can be regarded as an association between testosterone deficiency syndrome and related comorbidities.

AIM

To investigate the effectiveness of testosterone therapy in patients with type 2 diabetes (T2D) and androgen deficiency.

MATERIALS AND METHODS

Testosterone replacement therapy was carried out in 26 men with T2D and clinically or laboratory-confirmed androgen deficiency. The age of the subjects ranged from 35 to 69 years old. Laboratory studies included determinations of the concentration of the hormones estradiol, luteinizing hormone (LH), and prostate-specific antigen (PSA). The observation period was 9 months.

RESULTS

The average level of total blood testosterone in the subjects before treatment was 9.4 mol/l and was likely lower than that of the control group (19.3 ± 1.6 nmol/l). The levels of total testosterone in the subjects ranged from 3.9 nmol/l to 10.7 nmol/l, and hormone levels measuring less than 8.0 nmol/l were observed in only 11 patients. After a course of testosterone replacement therapy, a stabilization in total testosterone levels at the level of reference values (as compared to the start of treatment) was observed in the blood of men with T2D after 9 months of observation and the administration of the fourth injection (16.83 ± 0.75 nmol/l).

CONCLUSION

The use of long-acting injectable testosterone undecanoate leads to normalization of total testosterone levels in the blood of men with T2D and androgen deficiency, and LH levels in these patients are unlikely to change.

An autofluorescence-based isolation of Leydig cells for testosterone deficiency treatment

Effective procedures for the purification of Leydig cells (LCs) can facilitate functional studies and transplantation therapies. However, current methods to purify LCs from testes are still far from satisfactory. Here, we found that testicular autofluorescence existed in the interstitium along with the gradual maturation of LCs from birth to adulthood. These autofluorescent cells were further isolated by fluorescence-activated cell sorting (FACS) and determined to be composed of LCs and macrophages. To further purify LCs, we combined two fluorescence channels of FACS and successfully separated LCs and macrophages. Of note, we confirmed that the obtained LCs not only possessed high purity, viability and quantity but also had intact steroidogenic activity and excellent responsiveness to luteinizing hormone. Moreover, subcutaneous transplantation of isolated LCs could alleviate the symptoms of testosterone deficiency in castrated mice. In summary, we established an effective autofluorescence-based method for isolating LCs. This method will aid in the future success of using LCs for basic and translational applications.

Low lean mass is associated with lower urinary tract symptoms in US men from the 2005-2006 national health and nutrition examination survey dataset

We investigated the relationship between low lean mass (LLM) and lower urinary tract symptoms (LUTS) using the 2005–2006 National Health and Nutrition Examination Survey (NHANES) dataset. We enrolled 959 men with an average age of 52.08 ± 7.91 years and performed weighted multiple regression analysis to determine the independent relationship between exposure variables (LLM, alternate LLM) and outcomes variables (urinary hesitancy, incomplete emptying, urinary frequency, nocturia, daytime LUTS, clinical LUTS) after adjusting for confounding factors. The prevalence of urinary hesitancy (OR = 7.76, P < 0.0001), incomplete emptying (OR = 2.49, P = 0.0070), urinary frequency (OR = 3.28, P < 0.0001), daytime LUTS (OR = 3.88, P < 0.0001) and clinical LUTS (OR = 8.11, P < 0.0001) was significantly higher among men with LLM compared to men without LLM. Moreover, alternate LLM (ALLM) was positively associated with urinary hesitancy (OR = 17.97, P < 0.0001), incomplete emptying (OR = 4.68, P = 0.0003), daytime LUTS (OR = 2.47, P = 0.0136) and clinical LUTS (OR = 12.18, P < 0.0001). These findings demonstrate that both LLM and ALLM were associated with a higher risk of LUTS in men aged ≥ 40 years, which suggested that early management and treatment of lean mass loss may improve or alleviate LUTS.

Case of Anorchia in a Mixed-Breed Dog

Anorchia is a rare and often poorly understood disorder of sexual development. In the present case report, we used a multidisciplinary approach to diagnose a case of anorchia in a 30-month old dog. The diagnostic process began with gathering the dog medical history followed by a clinical visit with the patient, which included a general wellness examination as well as an examination of the genital system. As suggested in the relevant literature, the dog underwent an ultrasound and then computed tomography (CT) of the genital system, which confirmed the diagnosis of testicular agenesis. Genetic testing confirmed the male XY karyotype. Hormone testing also supported the diagnosis: testosterone and anti-Müllerian hormone levels were below their reference ranges, and luteinizing hormone (LH) was above 1 ng/mL. Following the diagnostic procedures suggested in the relevant literature, the present study confirms anorchia in the dog and describes a case of testicular agenesis in the canine species.

Testosterone Disorders and Male Hypogonadism in Kidney Disease

Chronic kidney disease (CKD) causes substantial alterations in the male endocrine system, which affect puberty, libido, and sexual function. A major effect of CKD is a reduction in testosterone levels because of both primary and hypogonadotrophic hypogonadism. In addition to impairment of pubertal growth and sexual maturation in children with CKD, clinical evidence suggests that uremic hypogonadism strongly contributes to several CKD complications, including erectile dysfunction, muscle wasting and frailty, anemia, decreased bone mineralization, depression, and cognitive impairment. This review focuses on a reappraisal of the physiologic role of testosterone, with an emphasis on the hypogonadal condition linked to CKD and its complications.

Transplantation of encapsulated human Leydig-like cells: A novel option for the treatment of testosterone deficiency

Previous studies have demonstrated that the transplantation of alginate-poly-ʟ-lysine-alginate (APA)-encapsulated rat Leydig cells (LCs) provides a promising approach for treating testosterone deficiency (TD). Nevertheless, LCs have a limited capacity to proliferate, limiting the efficacy of LC transplantation therapy. Here, we established an efficient differentiation system to obtain functional Leydig-like cells (LLCs) from human stem Leydig cells (hSLCs). Then we injected APA-encapsulated LLCs into the abdominal cavities of castrated mice without an immunosuppressor. The APA-encapsulated cells survived and partially restored testosterone production for 90 days in vivo. More importantly, the transplantation of encapsulated LLCs ameliorated the symptoms of TD, such as fat accumulation, muscle atrophy and adipocyte accumulation in bone marrow. Overall, these results suggest that the transplantation of encapsulated LLCs is a promising new method for testosterone supplementation with potential clinical applications in TD.

Human reproductive behavior, life history, and the Challenge Hypothesis: A 30-year review, retrospective and future directions

The Challenge Hypothesis (Wingfield et al., 1990) originally focused on adult male avian testosterone elevated in response to same-sex competition in reproductive contexts. The purpose of the present paper is to demonstrate how the Challenge Hypothesis has shaped ideas about human life histories. We conduct a citation analysis, drawing upon 400 Google Scholar citations in the human literature to identify patterns in this body of scholarship. We cover key factors, such as context and personality traits, that help explain variable testosterone responses such as winning/losing to adult competitive behavior. Findings from studies on courtship and sexual behavior indicate some variation in testosterone responses depending on factors such as motivation. A large body of research indicates that male testosterone levels are often lower in contexts of long-term committed partnerships and nurturant fathering and aligned with variation in male mating and parenting effort. As the Challenge Hypothesis is extended across the life course, DHEA and androstenedione (rather than testosterone) appear more responsive to juvenile male competitive behavior, and during reproductive senescence, baseline male testosterone levels decrease just as male life history allocations show decreased mating effort. We discuss how research on testosterone administration, particularly in older men, provides causal insight into effects of testosterone in humans, and how this "natural experiment" can be viewed in light of the Challenge Hypothesis. We synthesize central concepts and findings, such as an expanded array of costs of testosterone that inform life history tradeoffs between maintenance and reproductive effort, and we conclude with directions for future research.

Reductions in testosterone are not indicative of exercise performance decrement in male endurance athletes

Our findings indicate that the participants of an 18 week intensive endurance exercise training program experienced significant (p < 0.001) reductions in resting testosterone (-25 to -45% decrease from pre-training), with some reaching the clinical criteria for androgen deficiency during the training regimen. Nonetheless, none of the participants displayed any running performance decrement, in fact, the opposite occurred (+18.6% improvement; p < 0.05). These preliminary findings suggest acute decreases in testosterone in and of itself may not be entirely indicative of a compromised exercise performance potential although elements of reproductive and bone health may still be compromised.

Hypogonadism in Exercising Males: Dysfunction or Adaptive-Regulatory Adjustment?

For decades researchers have reported men who engaged in intensive exercise training can develop low resting testosterone levels, alterations in their hypothalamic-pituitary-gonadal (HPG) axis, and display hypogonadism. Recently there is renewed interest in this topic since the International Olympic Committee (IOC) Medical Commission coined the term "Relative Energy Deficiency in Sports" (RED-S) as clinical terminology to address both the female-male occurrences of reproductive system health disruptions associated with exercise. This IOC Commission action attempted to move beyond the sex-specific terminology of the "Female Athlete Triad" (Triad) and heighten awareness/realization that some athletic men do have reproductive related physiologic disturbances such as lowered sex hormone levels, HPG regulatory axis alterations, and low bone mineral density similar to Triad women. There are elements in the development and symptomology of exercise-related male hypogonadism that mirror closely that of women experiencing the Triad/RED-S, but evidence also exists that dissimilarities exist between the sexes on this issue. Our research group postulates that the inconsistency and differences in the male findings in relation to women with Triad/RED-S are not just due to sex dimorphism, but that there are varying forms of exercise-related reproductive disruptions existing in athletic men resulting in them displaying a relative hypogonadism condition. Specifically, such conditions in men may derive acutely and be associated with low energy availability (Triad/RED-S) or excessive training load (overtraining) and appear transient in nature, and resolve with appropriate clinical interventions. However, manifestations of a more chronic based hypogonadism that persists on a more permanent basis (years) exist and is termed the "Exercise Hypogonadal Male Condition." This article presents an up-to-date overview of the various types of acute and chronic relative hypogonadism found in athletic, exercising men and proposes mechanistic models of how these various forms of exercise relative hypogonadism develop.

Low testosterone: Androgen deficiency, endurance exercise training, and competitive performance

Purpose

Our intent was to (a) characterize weekly changes in resting testosterone (T), cortisol (C), and the T:C ratio in males during an intensive endurance training program, and (b) determine if clinical androgen deficiency (AD) based upon T-level criteria developed.

Methods

An 18-week training program in which individual training volume (km/week) increased at 25% increments over baseline (BL) levels observed prior to the study beginning at 4-week intervals throughout the first 12 weeks. After 12 weeks, the volume was reduced to that of the first 4 weeks until the study end (week 18). Competitive performance running tests were assessed at BL and every 4 weeks, while blood T and C were assessed weekly.

Results

Performance improved from BL at weeks 4–16 (p < 0.01). T was reduced (p < 0.01) from BL at weeks 3, and 5–18. The greatest reduction from BL was at week 13, subsequently T returned toward BL at week 18. C was highly variable, and no significant changes from BL were noted. The T:C ratio at weeks 5, 6, and 8–16 was significantly less than at BL (p < 0.01), the greatest reduction at week 13. The T:C ratio values also returned toward BL by week 18. Finally, ∼50% of the subjects reached T levels to be classified as AD.

Conclusions

Sports scientists should recognize decreases in T or T:C ratio is not always indicative of compromised competitive performance potential. Clinicians should be aware increased training loads can lead to AD in men.

Digit ratio (2D:4D) and testosterone supplementation

BACKGROUND

Testosterone (T) is taken or prescribed to enhance appearance, increase athletic performance and libido and to treat hypogonadism. Digit ratio (2D:4D) is thought to be a negative correlate of prenatal T. Here we consider the relationship between 2D:4D and T supplementation.

AIMS

Our sample was taken from the BBC internet study. Respondents were asked (y/n) if they were taking; (i) T, (ii) hormone replacement therapy with T (HRTwT). We removed extreme 2D:4D values and age and considered the most numerous ethnic group (i.e. "Whites"). Analyses were performed with a two-factor (sex*T) analysis of variance with covariate age and dependent variables 2D:4D or right-left 2D:4D (Dr-l).

RESULTS

Out of 197,589 respondents, 793 (598 males) reported taking T. There was a significant main effect for right 2D:4D such that T supplementing males had higher 2D:4D than those who did not. The sex*T interaction was significant, but the effect reversed in females. There were 22,576 (661 males) participants who reported taking HRTwT. We found a significant main effect for right 2D:4D, males taking HRTwT had higher 2D:4D than those who did not. This was reversed in females. The sex*HRTwT interaction was significant, a high Dr-l was also found in males reporting HRTwT.

CONCLUSION

Males who reported taking T or HRTwT had high right 2D:4D and/or Dr-l. The situation with females may be the reverse of that found in males but effect sizes are less. The health implications of an association between high (feminized) 2D:4D and T supplementation in males are discussed.

Testosterone Supplementation and Cognitive Functioning in Men-A Systematic Review and Meta-Analysis

Testosterone supplementation (TS) is assumed important for cognitive functioning in men, but conflicting results have prevented firm conclusions. The current study systematically reviewed available randomized controlled trials (RCTs) on effects of TS on cognitive functioning in men, subjected the findings to meta-analysis, and explored between-study differences as possible moderators of the effects. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, two authors independently searched for eligible records in the electronic databases of PubMed, PsycINFO, Web of Science, the Cochrane Library, Cumulative Index of Nursing and Allied Health, and Embase and determined eligibility using the following (population, intervention, comparison, outcome) criteria: population, male adults (>18 years); intervention, TS; comparison, placebo; and outcome, results of standardized neuropsychological tests. Following duplicate removal, 3873 records were screened with 92 remaining for full-text screening. Twenty-one papers reporting results of 23 independent RCTs were included, of which none treated samples of clinically hypogonadal men. The small improvement found in overall cognitive functioning (Hedges g = 0.09; CI 95%: −0.02 to 0.19) failed to reach statistical significance (P = 0.108) and approached zero when adjusting for possible publication bias (g = 0.04). The effects for the 11 individual cognitive domains did not reach statistical significance (g: −0.04 to 0.19, P: 0.061 to 0.989). Small statistically significant (P < 0.05) effects were found for five study subsets but failed to meet the fail-safe criterion. The available evidence indicates that effects of TS on cognitive functioning in men with testosterone levels within normal ranges are less robust and of insufficient magnitude to be of clinical relevance. The effects in clinically hypogonadal men remain to be investigated.

Testosterone Deficiency, Weakness, and Multimorbidity in Men

The purposes of this study were to evaluate the association between total testosterone (TT) deficiency and weakness on multimorbidity in men. Analyses were performed to examine the prevalence of multimobidity among young, middle-aged, and older men, with and without testosterone deficiency. Multivariate logistic models were also used to determine the association between age-specific TT tertiles and multimorbidity, adjusting for key sociodemographic variables, as well as a secondary analysis adjusted for grip strength. Multimorbidity was more prevalent among men with testosterone deficiency, compared to normal TT in the entire group (36.6% vs 55.2%; p < 0.001); however, differences were only seen within young (testosterone deficiency: 36.4%; normal TT: 13.5%; p < 0.001) and older men (testosterone deficiency: 75.0%; normal TT: 61.5%; p < 0.001). Robust associations were found between the age-specific low-TT (OR: 2.87; 95%CI: 2.14–3.83) and moderate-TT (OR: 1.67; 95%CI: 1.27–2.20) tertiles (reference high-TT) and multimorbidity. Secondary analysis demonstrated that both low TT (OR: 1.82; 95%CI: 1.29–2.55) and moderate-TT (OR: 1.31; 95%CI: 1.01–1.69) were associated with multimorbidity, even after adjusting for obesity (OR: 1.75; 95%CI: 1.07–2.87) and NGS (OR: 1.21 per 0.05 unit lower NGS). Low TT and weakness in men were independently associated with multimorbidity at all ages; however, multimorbidity was more prevalent among young and older men with testosterone deficiency.

Orchiectomy and letrozole differentially regulate synaptic plasticity and spatial memory in a manner that is mediated by SRC-1 in the hippocampus of male mice

Hippocampal synaptic plasticity is the basis of spatial memory and cognition and is strongly regulated by both testicular androgens (testosterone, T) and hippocampal estrogens (17β-estradiol, E2) converted from T by aromatase, which is inhibited by letrozole (LET), but the contribution of each pathway to spatial memory and the associated mechanisms are unclear. In this study, we first used orchiectomy (ORX) and LET injection to investigate the effects of T and hippocampal E2 on spatial memory and hippocampal synaptic plasticity. Next, we examined the changes in steroid receptors and steroid receptor coactivator-1 (SRC-1) under these treatments. Finally, we constructed an SRC-1 RNA interference lentivirus and an AROM overexpression lentivirus to explore the roles of SRC-1 under T replacement and AROM overexpression. The results revealed spatial memory impairment only after LET. LET induced more actin depolymerization and greater losses of spines, synapses, and postsynaptic proteins compared with ORX. Moreover, although ERα and ERβ were affected by LET and ORX at similar levels, AR, GPR30, and SRC-1 were dramatically decreased by LET compared with ORX. Finally, the T and AROM overexpression-induced changes in synaptic proteins and actin polymerization were blocked by SRC-1 inhibition. These results demonstrate that testicular androgens play a limited role, whereas local E2 is more important for cognition, which may explain why castrated men such as eunuchs usually do not have cognitive disorders. These results also suggest a pivotal role of SRC-1 in the action of steroids; thus, SRC-1 may serve as a novel therapeutic target for cognitive disorders.

Steroid Receptor Coactivator-1 Knockdown Decreases Synaptic Plasticity and Impairs Spatial Memory in the Hippocampus of Mice

Steroids have been demonstrated to play profound roles in the regulation of hippocampal function by acting on their receptors, which need coactivators for their transcriptional activities. Previous studies have shown that steroid receptor coactivator-1 (SRC-1) is the predominant coactivator in the hippocampus, but its exact role and the underlying mechanisms remain unclear. In this study, we constructed SRC-1 RNA interference (RNAi) lentiviruses, injected them into the hippocampus of male mice, and then examined the changes in the expression of selected synaptic proteins, CA1 synapse density, postsynaptic density (PSD) thickness, and in vivo long-term potentiation (LTP). Spatial learning and memory behavior changes were investigated using the Morris water maze. We then transfected the lentiviruses into cultured hippocampal cells and examined the changes in synaptic protein and phospho-cyclic AMP response element-binding protein (pCREB) expression. The in vivo results showed that SRC-1 knockdown significantly decreased the expression of synaptic proteins and CA1 synapse density as well as PSD thickness; SRC-1 knockdown also significantly impaired in vivo LTP and disrupted spatial learning and memory. The in vitro results showed that while the expression of synaptic proteins was significantly decreased by SRC-1 knockdown, pCREB expression was also significantly decreased. The above results suggest a pivotal role of SRC-1 in the regulation of hippocampal synaptic plasticity and spatial learning and memory, strongly indicating SRC-1 may serve as a novel therapeutic target for hippocampus-dependent memory disorders.

Variation in Practice Pattern of Male Hypogonadism: A Comparative Analysis of Primary Care, Urology, Endocrinology, and HIV Specialists

The objective of the current study was to measure the adherence of guideline-based evaluation and treatment of hypogonadism by medical specialty. A retrospective review was performed analyzing patients from a single academic institution within the past 10 years. The cohort of 193 men was grouped according to medical specialty of the diagnosing physician (50 urology, 49 primary care, 44 endocrinology, and 50 HIV medicine). Adherence to guidelines was assessed using the Endocrine Society's criteria. Primary care patients were older compared to the rest of the cohort ( p < .001) but BMI and cardiovascular risk factors were similar ( p = .900). Patients treated by urologists and endocrinologists had the highest percentage of low testosterone findings at initial encounter at 72% ( p < .001). Sixty-two percent of urology patients had low LH or FSH compared to 63.6% for endocrinology and 16% for primary care ( p < .001). As for brain MRI findings, no urology patients had positive findings (0/9) while eight pituitary adenomas (40%) were found by endocrinologists. Forty-five percent of men treated by urologists received TRT without repeat confirmation, compared to 58% of endocrinologists, 77% of primary care, and 88% of HIV medicine ( p < .001). All urology patients had PSA checked before TRT compared to 77.5% of primary care and 61.2% of endocrinology patients ( p = .063). Adherence to the guidelines helps prevent undue over-diagnosis and over-treatment of hypogonadism. This study suggests that adherence to guideline-based screening is varied among specialties.

A Content Analysis of Testosterone Websites: Sex, Muscle, and Male Age-Related Thematic Differences

Male testosterone supplementation is a large and growing industry. How is testosterone marketed to male consumers online? The present exploratory study entailed a content coding analysis of the home pages of 49 websites focused on testosterone supplementation for men in the United States. Four hypotheses concerning anticipated age-related differences in content coding were also tested: more frequent longevity content toward older men, and more frequent social dominance/physical formidability, muscle, and sex content toward younger men. Codes were created based on inductive observations and drawing upon the medical, life history, and human behavioral endocrinology literatures. Approximately half ( n = 24) of websites were oriented toward younger men (estimated audience of men 40 years of age or younger) and half ( n = 25) toward older men (estimated audience over 40 years of age). Results indicated that the most frequent content codes concerned online sales (e.g., product and purchasing information). Apart from sales information, the most frequent codes concerned, in order, muscle, sex/sexual functioning, low T, energy, fat, strength, aging, and well-being, with all four hypotheses also supported. These findings are interpreted in the light of medical, evolutionary life history, and human behavioral endocrinology approaches.

Health-related physical fitness and quality of life in men with congenital hypogonadotropic hypogonadism

Congenital hypogonadotropic hypogonadism is a rare disorder characterised by impaired testosterone secretion since birth, and represents a valuable model for studying the effects of testosterone replacement therapy (TRT) in humans. This cross-sectional study aimed to investigate all health-related physical fitness (HRPF) components and quality of life in a series of eight men with hypogonadotropic hypogonadism under regular TRT. The study group was compared to a control group of 16 healthy subjects paired for age, body mass index and physical activity. Body composition, aerobic capacity, muscular strength and endurance, and joint flexibility were evaluated in two different 7-day interval time points, based on the pharmacokinetics of testosterone in the hypogonadal group. Quality of life was assessed by the WHOQOL-brief questionnaire. Both groups had similar performances in all HRPF components evaluated, independently of plasma testosterone levels (p > .05). Quality of life was also similar in the four domains analysed (p > .05). The results of this pilot study suggest that regular testosterone replacement was efficient in providing HRPF and quality of life in a series of congenitally hypogonadal men to levels like those observed in healthy men. In addition, acute fluctuations in plasma testosterone did not correlate with changes in muscle strength and endurance.

Gonadal dysfunction in adult male patients with thalassemia major: an update for clinicians caring for thalassemia

INTRODUCTION

Hypogonadism is the most frequently reported endocrine complication, affecting 40%-80% of thalassemia major (TM) patients. The prevalence and severity of hypogonadism in TM varies among studies, depending on patients' age, genotype, transfusion frequency and starting age and efficiency of iron chelation. Areas covered: The diagnosis requires careful clinical assessment and appropriate laboratory testing. Its management is more complex compared to other 'classical' causes of hypogonadism because of multiple associated disorders (cardiac, hepatic and endocrine) and other contributing factors basically iron overload and iron toxicity. Expert commentary: Early recognition and treatment of hypogonadism in TM patients is most important to prevent late complications and to enhance the chances of parenthood. The goal of management is to restore deficient glandular function. If fertility is the issue and the testis is under-stimulated because of gonadotropin deficiency, it is possible to induce or restore spermatogenesis with exogenous gonadotropins in some patients. Assisted reproductive techniques may supplementary help to overcome previously untreatable causes of male infertility. These positive achievements should encourage health care providers to pay closer attention to the reproductive health of TM patients. This would involve the collaboration of clinicians caring for thalassemia with endocrinologists and specialists in assisted reproductive technologies.

Genetics of Sex Hormone-Binding Globulin and Testosterone Levels in Fertile and Infertile Men of Reproductive Age

Context

Testosterone (T) is a central androgenic hormone, and sex hormone-binding globulin (SHBG) is the major determinant of its bioactivity. There are no acknowledged genetic variants with clear-cut clinical implications, modulating T levels in men.

Objective

To confirm genetic associations of top loci (SHBG, GCKR, SLCO1B1, and JMJD1C) from genome-wide association (GWA) studies for serum SHBG and T.

Design Patients

Groups differing in general and reproductive parameters: young men (n = 540; 19.3 ± 1.8 years), severe idiopathic male infertility patients (n = 641; 31.6 ± 6.0 years), and male partners of pregnant women (n = 324; 31.9 ± 6.6 years). All patients were recruited at the Andrology Centre, Tartu University Hospital, Estonia.

Main Outcome Measures

Genetic associations with reproductive hormones, testicular and sperm parameters (linear regression, additive model); intergroup allele/genotype distribution comparisons.

Results

Associations with serum SHBG levels were robust for SHBG -68 G>A [rs1799941; meta-analysis: P = 3.7 × 10^-14; allelic effect (standard error) = 4.67 (0.62) nmol/L], SHBG +1091 C>T [rs727428; P = 7.3 × 10^-11; -3.74 (0.57)], SHBG Pro185Leu [rs6258; P = 1.2 × 10^-4, -12.2 (3.17)], and GCKR Pro446Leu [rs1260326; P = 1.5 × 10^-4; -2.2 (0.59)]. Measured T concentrations correlated with genetically modulated levels of SHBG (r = 0.48 to 0.74, P < 0.0001), guaranteeing stable availability of free T. Among infertile men, SHBG Pro185Leu substitution showed additional downstream effect on luteinizing hormone [P = 5.1 × 10^-5; -1.66 (0.57) IU/L] and follicle-stimulating hormone [P = 3.4 × 10^-3; -2.48 (1.23) IU/L]. No associations with male reproductive parameters were detected for SHBG Asp327Asn (rs6259), SLCO1B1 Val174Ala (rs4149056), and JMJD1C intronic variant rs7910927.

Conclusions

Claims were replicated and additional associations were detected for four of seven tested GWAS top loci. Perspective clinical investigations of these variants are hypotestosteronemia among aging men and pharmacogenetics of hormone replacement therapy.

The relationship of salivary testosterone and male sexual dysfunction in opioid-associated androgen deficiency (OPIAD)

BACKGROUND

Opioids are an effective treatment for chronic non-malignant pain (CNP). Long-term use risks and side effects such as opioid-induced androgen deficiency (OPIAD) exist. This could be measured by saliva testosterone (Sal-T).

OBJECTIVES

To evaluate OPIAD in long-term opioid use in CNP patients.

METHODS

A cross-sectional study included CNP male outpatients under opioid treatment. Total-Testosterone (Total-T), Free-Testosterone (Free-T), Bio-Testosterone (Bio-T) and Sal-T were measured. Correlations were calculated by Spearman's rho (SPSS 20).

RESULTS

From 2012 to 2014, 134 from 249 (54%) consecutive male outpatients reported erectile dysfunction (ED), 37% of them related to opioids and 19% evidenced OPIAD. A total of 120 subjects (94 cases and 26 matched-controls) were included. A significantly lower luteinizing hormone, Total-T and Free-T were found, as well as, a significant correlation between Sal-T and Total-T (r = 0.234, p = 0.039), Bio-T (r = 0.241, p = 0.039), IIEF (r = 0.363, p = 0.003) and HAD-anxiety (r = -0.414, p = 0.012) in OPIAD patients. Sal-T levels were significantly lower in patients with severe-moderate ED versus mild ED (p = 0.045) and in patients with severe ED versus moderate-mild ED (p = 0.036).

CONCLUSIONS

These data demonstrate the high prevalence of ED in long-term use of opioids, part of this is associated to OPIAD, which can be tested by Sal-T as a non-invasive approach.

Sexual Dysfunction in Type 2 Diabetes at Diagnosis: Progression over Time and Drug and Non-Drug Correlated Factors

Aims

To present the longitudinal data of the SUBITO-DE study, a prospective survey involving male patients with new or recently diagnosed type 2 diabetes mellitus (T2DM) (<24 months).

Materials and Methods

Sexual function was assessed in male patients with T2DM at baseline (phase 1) and after a mean follow-up of 18 months (phase 2). Standard metabolic parameters and sexual and depressive symptoms were evaluated.

Results

Six of the 499 enrolled patients died of different causes during phase 1. Of the 493 surviving men invited to participate in phase 2, 450 (mean age 59.0±9.0 years) (90.2%) accepted and 43 (8.2%) were lost to follow-up. As compared to baseline, the proportion of the men who reported improvement in erectile dysfunction (ED) at follow-up was nearly double that of the men who reported worsening of ED (22.6% vs. 12.8%). The increase in frequency of sexual activity the men reported at follow-up assessment indicates that many never treated before baseline were taking an ED drug during the study period (106 subjects). Phosphodiesterase type 5 inhibitors (PDE5i) were the ED drugs most commonly taken at both baseline and follow-up. An overall improvement over baseline values was observed in metabolic targets for T2DM and depressive symptoms. Conversely, no change in lifestyle behaviors was recorded during the study.

Conclusions

Sexual dysfunction is a major concern in men with T2DM. The SUBITO-DE study demonstrates that, when combined with adequate counseling and tailored PDE5i therapy, an integrated approach to achieving metabolic targets in men with T2DM can improve sexual function as well as depressive symptoms.

Oxidation-reduction potential of semen: what is its role in the treatment of male infertility?

The diagnosis of male infertility relies largely on conventional semen analysis, and its interpretation has a profound influence on subsequent management of patients. Despite poor correlation between conventional semen parameters and male fertility potential, inclusion of advanced semen quality tests to routine male infertility workup algorithms has not been widely accepted. Oxidative stress is one of the major mediators in various etiologies of male infertility; it has deleterious effects on spermatozoa, including DNA damage. Alleviation of oxidative stress constitutes a potential treatment strategy for male infertility. Measurement of seminal oxidative stress is of crucial role in the identification and monitoring of patients who may benefit from treatments. Various tests including reactive oxygen species (ROS) assay, total antioxidant capacity (TAC) assay or malondialdehyde (MDA) assay used by different laboratories have their own drawbacks. Oxidation-reduction potential (ORP) is a measure of overall balance between oxidants and antioxidants, providing a comprehensive measure of oxidative stress. The MiOXSYS™ System is a novel technology based on a galvanostatic measure of electrons; it presents static ORP (sORP) measures with static referring to the passive or current state of activity between oxidants and antioxidants. Preliminary studies have correlated sORP to poor semen qualities. It is potentially useful in prognostication of assisted reproductive techniques outcomes, screening of antioxidants either in vivo or during IVF cycles, identification of infertile men who may benefit from treatment of oxidative stress, and monitoring of treatment success. The simplified laboratory test requiring a small amount of semen would facilitate clinical application and research in the field. In this paper, we discuss the measurement of ORP by the MiOXSYS System as a real-time assessment of seminal oxidative stress, and argue that it is a potential valuable clinical test that should be incorporated into the male infertility workup and become an important guide to the treatment of oxidative stress-induced male infertility.

Controversies and Advances With Testosterone Therapy: A 40-Year Perspective

Testosterone therapy (TTh) has become highly controversial. There are important health consequences of testosterone deficiency, and meaningful benefits with treatment. There is level 1 evidence that TTh improves sexual function and desire, body composition, and bone density. Concerns regarding cardiovascular risk were based on two deeply flawed retrospective studies and are contradicted by dozens of studies showing cardiovascular benefits of TTh or higher endogenous testosterone, including placebo-controlled studies in men with known heart disease (angina, heart failure). Prostate cancer should no longer be considered a risk of TTh. Testosterone is neither scourge nor panacea--it is just good medicine.