Testosterone and dihydrotestosterone and incident ischaemic stroke in men in the Cardiovascular Health Study

A protective role of genetically predicted sex hormone-binding globulin on stroke

Introduction

The role of sex hormone-binding globulin (SHBG) on stroke has been investigated in several observational studies. To provide the causal estimates of SHBG on stroke and its subtypes, bi-directional and multivariable Mendelian randomization (MR) analyses are performed.

Methods

The genetic instruments of SHBG were obtained from the UK Biobank. Outcome datasets for stroke and its subtypes were taken from the MEGASTROKE Consortium. The main analysis used in this study is the inverse variance weighting, complemented by other sensitivity approaches to verify the conformity of findings.

Results

We found that the risk of stroke grew by 13% (odd ratio [OR] = 0.87, 95% confidence interval [CI] = 0.79-0.95, P = 0.0041) and the risk of ischemic stroke grew by 15% (OR = 0.85, 95%CI = 0.77-0.95, P = 0.0038) caused by genetically predicted SHBG. The causal association remains robust in the reverse MR and multivariable MR analyses for stroke (reverse MR: all P > 0.01 for the IVW method; MVMR: OR = 0.72, 95%CI = 0.59-0.87, P = 0.0011) and ischemic stroke (reverse MR: all P > 0.01 for IVW; MVMR: OR = 0.70, 95%CI = 0.56-0.86, P = 0.0007).

Conclusion

Our MR study provides novel evidence that SHBG has an inverse association with stroke and ischemic stroke, exerting protective effects on stroke.

Associations of Serum Testosterone and Sex Hormone-Binding Globulin With Incident Cardiovascular Events in Middle-Aged to Older Men

BACKGROUND

The influence of testosterone on risk for cardiovascular events in men is uncertain. Previous observational studies of sex hormones and incident cardiovascular disease in men have reported inconsistent findings, limited by cohort sizes and different selection criteria.

OBJECTIVE

To analyze associations of serum total testosterone and sex hormone-binding globulin (SHBG) with incident cardiovascular events in men.

DESIGN

Cohort study.

SETTING

UK Biobank prospective cohort.

PARTICIPANTS

Community-dwelling men aged 40 to 69 years.

MEASUREMENTS

Testosterone and SHBG were assayed, and free testosterone was calculated. Cox proportional hazards regression was done, with outcomes of incident myocardial infarction (MI), hemorrhagic stroke (HS), ischemic stroke (IS), heart failure (HF), and major adverse cardiovascular events (MACE), adjusted for sociodemographic, lifestyle, and medical factors.

RESULTS

Of 210 700 men followed for 9 years, 8790 (4.2%) had an incident cardiovascular event. After adjustment for key variables, lower total testosterone concentrations (quintile 1 vs. quintile 5) were not associated with incident MI (fully adjusted hazard ratio [HR], 0.89 [95% CI, 0.80 to 1.00]), HS (HR, 0.94 [CI, 0.70 to 1.26]), IS (HR, 0.95 [CI, 0.82 to 1.10]), HF (HR, 1.15 [CI, 0.91 to 1.45]), or MACE (HR, 0.92 [CI, 0.84 to 1.00]). Men with lower calculated free testosterone values had a lower incidence of MACE (HR, 0.90 [CI, 0.84 to 0.97]). Lower SHBG concentrations were associated with higher incidence of MI (HR, 1.23 [CI, 1.09 to 1.38]) and lower incidence of IS (HR, 0.79 [CI, 0.67 to 0.94]) and HF (HR, 0.69 [CI, 0.54 to 0.89]), but not with HS (HR, 0.81 [CI, 0.57 to 1.14]) or MACE (HR, 1.01 [CI, 0.92 to 1.11]).

LIMITATION

Observational study; single baseline measurement of testosterone and SHBG.

CONCLUSION

Men with lower total testosterone concentrations were not at increased risk for MI, stroke, HF, or MACE. Calculated free testosterone may be associated with risk for MACE. Men with lower SHBG concentrations have higher risk for MI but lower risk for IS and HF, with causality to be determined.

PRIMARY FUNDING SOURCE

Western Australian Health Translation Network, Medical Research Future Fund, and Lawley Pharmaceuticals.

Systematic review and meta-analyses on associations of endogenous testosterone concentration with health outcomes in community-dwelling men

OBJECTIVES

The overall study aim is to clarify the relation of endogenous sex hormones with major health outcomes in men. This paper reports a systematic review focusing on published estimates for testosterone associations.

SETTING

Community-dwelling men.

PARTICIPANTS

20 180 adult men participated in the final set of studies identified and selected from a systematic review. Eligible studies included prospective cohort studies with plasma or serum testosterone concentrations measured for adult men using mass spectrometry with at least 5 years of follow-up data and one of the specified outcome measures recorded. Only published or grey literature items written in English were considered.

PRIMARY AND SECONDARY OUTCOME MEASURES

Planned prospective outcome measures: cardiovascular disease (CVD) events, CVD deaths, all-cause mortality, cancer deaths, cancer diagnoses, cognitive decline, dementia. Meta-analyses were of the most frequently reported outcomes in selected studies: CVD deaths and all-cause mortality. Succinct characterisations of testosterone associations with other outcomes are also presented.

RESULTS

Screening of 1994 deduplicated items identified 9 suitable studies, with an additional 2 identified by colleagues (11 in total). Summary estimates of mean testosterone concentration and age at recruitment for 20 180 adult men were 15.4±0.7 nmol/L and 64.9±3.3 year. Despite considerable variation in mean testosterone, a metaregression estimated no significant dependence on mean age at recruitment among studies (slope=-0.03, 95% CI -0.11 to 0.06). Meta-analyses demonstrated negligible heterogeneity and no significant effect of a 5 nmol/L increase in testosterone on the risk of all-cause mortality (HR=0.96, 95% CI 0.89 to 1.03) or death from CVD (HR=0.95, 95% CI 0.83 to 1.08).

CONCLUSIONS

Analyses of published estimates did not demonstrate associations of endogenous testosterone with CVD deaths or with all-cause mortality. Suggested further research includes the planned individual participant data meta-analyses for selected studies, enabling the investigation of non-linear summary effects.

PROSPERO REGISTRATION NUMBER

PROSPERO: CRD42019139668.

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.

Testosterone, dihydrotestosterone, bone density, and hip fracture risk among older men: The Cardiovascular Health Study

BACKGROUND

Little is known about the relationships of dihydrotestosterone (DHT), a more potent androgen than testosterone (T), with bone mineral density (BMD) and fracture risk. Our objectives were to evaluate the relationships of T, DHT and sex hormone binding globulin (SHBG) with BMD, fracture risk, and lean body mass (LBM).

METHODS

We evaluated 1128 older men free of cardiovascular disease in a prospective cohort study using data from the Cardiovascular Health Study. T and DHT were measured by liquid chromatography-tandem mass spectrometry and SHBG by fluoroimmunoassay. Our outcomes included incident hip fracture (n = 106) over a median of 10.2 years and BMD and LBM by dual-energy x-ray absorptiometry (n = 439).

RESULTS

In Cox regression models mutually adjusted for T, SHBG, and covariates, each standard deviation increment in DHT (0.23 ng/ml) was associated with a 26% lower risk of hip fracture (adjusted hazard ratio [aHR] 0.74, 95% confidence interval (CI) 0.55-1.00, p = 0.049). Similarly, SHBG was associated with fracture in mutually adjusted models (aHR HR 1.26, 95% CI, 1.01-1.58, p = 0.045). In contrast, T (aHR, 1.16, 95% CI, 0.86-1.56, p = 0.324) was not significantly associated with fracture in mutually adjusted models. T, DHT and SHBG were not associated with BMD. T and DHT were both positively associated with LBM in individual models.

CONCLUSIONS

In older men, DHT was inversely associated with hip fracture risk and SHBG was positively associated with hip fracture risk, while T was not. Future studies should elucidate the mechanisms by which DHT affects bone health.

Testosterone therapy in hypogonadal patients and the associated risks of cardiovascular events

Since the male secondary sex characters, libido and fertility are attributed to their major androgen hormone testosterone, the sub-optimum levels of testosterone in young adults may cause infertility and irregularities in their sexual behaviour. Such deficiency is often secondary to maladies involving testes, pituitary or hypothalamus that could be treated with an administration of exogenous testosterone. In the last few decades, the number of testosterone prescriptions has markedly increased to treat sub-optimal serum levels even though its administration in such conditions is not yet approved. On account of its associated cardiovascular hazards, the food and drug authority in the United States has issued safety alerts on testosterone replacement therapy (TRT). Owing to a great degree of conflict among their findings, the published clinical trials seem struggling in presenting a decisive opinion on the matter. Hence, the clinicians remain uncertain about the possible cardiovascular adversities while prescribing TRT in hypogonadal men. The uncertainty escalates even further while prescribing such therapy in older men with a previous history of cardiovascular ailments. In the current review, we analysed the pre-clinical and clinical studies to evaluate the physiological impact of testosterone on cardiovascular and related parameters. We have enlisted studies on the association of cardiovascular health and endogenous testosterone levels with a comprehensive analysis of epidemiological studies, clinical trials, and meta-analyses on the cardiovascular risk of TRT. The review is aimed to assist clinicians in making smart decisions regarding TRT in their patients.

Effectiveness of testosterone therapy in hypogonadal patients and its controversial adverse impact on the cardiovascular system

Testosterone is the major male hormone produced by testicles which are directly associated with man's appearance and secondary sexual developments. Androgen deficiency starts when the male hormonal level falls from its normal range though, in youngsters, the deficiency occurs due to disruption of the normal functioning of pituitary, hypothalamus glands, and testes. Thus, testosterone replacement therapy was already known for the treatment of androgen deficiency with lesser risks of producing cardiovascular problems. Since from previous years, the treatment threshold in the form of testosterone replacement therapy has effectively increased to that extent that it was prescribed for those conditions which it was considered as inappropriate. However, there are some research studies and clinical trials available that proposed the higher risk of inducing cardiovascular disease with the use of testosterone replacement therapy. Thus under the light of these results, the FDA has published the report of the increased risk of cardiovascular disease with the increased use of testosterone replacement therapy. Nevertheless, there is not a single trial available or designed that could evaluate the risk of cardiovascular events with the use of testosterone replacement therapy. As a result, the use of testosterone still questioned the cardiovascular safety of this replacement therapy. Thus, this literature outlines the distribution pattern of disease by investigating the data and link between serum testosterone level and the cardiovascular disease, also the prescription data of testosterone replacement therapy patients and their tendency of inducing cardiovascular disease, meta-analysis and the trials regarding testosterone replacement therapy and its connection with the risks of causing cardiovascular disease and lastly, the possible effects of testosterone replacement therapy on the cardiovascular system. This study aims to evaluate the available evidence regarding the use of testosterone replacement therapy when choosing it as a treatment plan for their patients.

Gonadal hormones and stroke risk: PCOS as a case study

It is well known that stroke incidence and outcome is sex-dependent and influenced by age and gonadal hormones. In post-menopausal and/or aged females, declining estrogen levels increases stroke risk. However, women who experience early menopause also have an increase in stroke risk. This suggests that, regardless of age, gonadal hormones regulate stroke risk and severity. This review discusses prolonged gonadal hormone dysfunction in a common female endocrine disorder known as polycystic ovarian syndrome, PCOS, and the associated increased risk of stroke due to resulting hyperandrogenism and metabolic comorbidities.

Independent ischemic stroke risk factors in older Americans: a systematic review

The Framingham Stroke Risk Profile (FSRP) is a validated model for predicting 10-year ischemic stroke risk in middle-aged adults, yet has not been demonstrated to consistently translate in older populations. This is a systematic review of independent risk factors measured among > 65 year olds, with subsequent first ischemic stroke, using PRISMA guidelines. We appraised peer-reviewed publications that included participants > 65 years old at risk assessment. Combined with other criteria, results were abstracted from 28 papers reporting six types of stroke risk factors: Serologic/Diagnostic, Conventional, Psychosocial, Genetic, Cognitive, and Antibiotic use. These studies demonstrated levels of serum androgens, C-reactive protein, and advanced glycation endproducts; thrombin generation; left ventricular mass; depressive symptoms; phosphodiesterase 4D single nucleotide polymorphisms; coagulation factor XII gene; peak thrombus generation; and lower cognitive functioning were independent risk factors for ischemic stroke in older adults. Plasma adipokines, free fatty acids and antibiotic use did not predict ischemic stroke. Purpose in life and APOEε2 allele were protective for ischemic stroke. This systematic review provides evidence of risk and protective factors for ischemic stroke in older cohorts that are not included in the FSRP. Further studies are needed to understand whether these factors are important enough to comprise a risk score.

Androgens In Men Study (AIMS): protocol for meta-analyses of individual participant data investigating associations of androgens with health outcomes in men

INTRODUCTION

This study aims to clarify the role(s) of endogenous sex hormones to influence health outcomes in men, specifically to define the associations of plasma testosterone with incidence of cardiovascular events, cancer, dementia and mortality risk, and to identify factors predicting testosterone concentrations. Data will be accrued from at least three Australian, two European and four North American population-based cohorts involving approximately 20 000 men.

METHODS AND ANALYSIS

Eligible studies include prospective cohort studies with baseline testosterone concentrations measured using mass spectrometry and 5 years of follow-up data on incident cardiovascular events, mortality, cancer diagnoses or deaths, new-onset dementia or decline in cognitive function recorded. Data for men, who were not taking androgens or drugs suppressing testosterone production, metabolism or action; and had no prior orchidectomy, are eligible. Systematic literature searches were conducted from 14 June 2019 to 31 December 2019, with no date range set for searches. Aggregate level data will be sought where individual participant data (IPD) are not available. One-stage IPD random-effects meta-analyses will be performed, using linear mixed models, generalised linear mixed models and either stratified or frailty-augmented Cox regression models. Heterogeneity in estimates from different studies will be quantified and bias investigated using funnel plots. Effect size estimates will be presented in forest plots and non-negligible heterogeneity and bias investigated using subgroup or meta-regression analyses.

ETHICS AND DISSEMINATION

Ethics approvals obtained for each of the participating cohorts state that participants have consented to have their data collected and used for research purposes. The Androgens In Men Study has been assessed as exempt from ethics review by the Human Ethics office at the University of Western Australia (file reference number RA/4/20/5014). Each of the component studies had obtained ethics approvals; please refer to respective component studies for details. Research findings will be disseminated to the scientific and broader community via the publication of four research articles, with each involving a separate set of IPD meta-analyses (articles will investigate different, distinct outcomes), at scientific conferences and meetings of relevant professional societies. Collaborating cohort studies will disseminate findings to study participants and local communities.

PROSPERO REGISTRATION NUMBER

CRD42019139668.

Acute Ultraviolet Light Exposure and Post-Resistance Exercise Serum Testosterone: A Pilot Study in Older Men

Testosterone deficiency is linked to a multitude of conditions including depression, sexual dysfunction, and cognitive impairment. Although synthetic testosterone-boosting pharmaceuticals have gained wide use, recent data suggests that vitamin D, ingested orally, may positively impact serum testosterone. Furthermore, evidence tying ultraviolet (UV) light exposure to endogenous vitamin D synthesis presents an intriguing possibility for naturally enhancing serum testosterone. This investigation sought to determine the effect of acute UV light exposure on resistance exercise-induced acute testosteronemia and vitamin D in older men. Six older adult men of varying activity levels (age 62 ± 1.79 yrs., height 179.92 ± 1.12 cm., body mass 83.79 ± 3.12 kg., BMI 25.95 ± 1.15 kg/m2) participated in two testing sessions separated by one week: 1) Resistance exercise followed by standard passive recovery (RERC) and 2) RE plus UV light exposure during the first 10-minutes of RE passive recovery (RERC-UV). The RE protocol was identical in both sessions and consisted of four sets of 10RM on leg press, chest press, and back row with 1-minute of rest between sets followed by 30-minutes of post-RE passive recovery. Serum testosterone and vitamin D were measured preand post-RE in 5-minute increments during the 30-minute recovery. Analysis of variance revealed neither RE or RERC-UV significantly affected serum testosterone or vitamin D. These findings suggest that acute UV light exposure may be insufficient to positively impact serum testosterone and vitamin D following a single bout of RE in older adult men.

Testosterone replacement therapy and cardiovascular risk

Testosterone is the main male sex hormone and is essential for the maintenance of male secondary sexual characteristics and fertility. Androgen deficiency in young men owing to organic disease of the hypothalamus, pituitary gland or testes has been treated with testosterone replacement for decades without reports of increased cardiovascular events. In the past decade, the number of testosterone prescriptions issued for middle-aged or older men with either age-related or obesity-related decline in serum testosterone levels has increased exponentially even though these conditions are not approved indications for testosterone therapy. Some retrospective studies and randomized trials have suggested that testosterone replacement therapy increases the risk of cardiovascular disease, which has led the FDA to release a warning statement about the potential cardiovascular risks of testosterone replacement therapy. However, no trials of testosterone replacement therapy published to date were designed or adequately powered to assess cardiovascular events; therefore, the cardiovascular safety of this therapy remains unclear. In this Review, we provide an overview of epidemiological data on the association between serum levels of endogenous testosterone and cardiovascular disease, prescription database studies on the risk of cardiovascular disease in men receiving testosterone therapy, randomized trials and meta-analyses evaluating testosterone replacement therapy and its association with cardiovascular events and mechanistic studies on the effects of testosterone on the cardiovascular system. Our aim is to help clinicians to make informed decisions when considering testosterone replacement therapy in their patients.

Chronic Testosterone Deprivation Sensitizes the Middle-Aged Rat Brain to Damaging Effects of Testosterone Replacement

INTRODUCTION

An increasing number of middle-aged men are being screened for low testosterone levels and the number of prescriptions for various forms of testosterone replacement therapy (TRT) has increased dramatically over the last 10 years. However, the safety of TRT has come into question with some studies suggesting increased morbidity and mortality.

OBJECTIVE

Because the benefits of estrogen replacement in postmenopausal women and ovariectomized rodents are lost if there is an extended delay between estrogen loss and replacement, we hypothesized that TRT may also be sensitive to delayed replacement.

METHODS

We compared the effects of testosterone replacement after short-term (2 weeks) and long-term testosterone deprivation (LTTD; 10 weeks) in middle-aged male rats on cerebral ischemia, oxidative stress, and cognitive function. We hypothesized that LTTD would increase oxidative stress levels and abrogate the beneficial effects of TRT.

RESULTS

Hypogonadism itself and TRT after short-term castration did not affect stroke outcome compared to intact rats. However, after long-term hypogonadism in middle-aged male Fischer 344 rats, TRT exacerbated the detrimental behavioral effects of experimental focal cerebral ischemia, whereas this detrimental effect was prevented by administration of the free-radical scavenger tempol, suggesting that TRT exacerbates oxidative stress. In contrast, TRT improved cognitive performance in non-stroked rats regardless of the length of hypogonadism. In the Morris water maze, peripheral oxidative stress was highly associated with decreased cognitive ability.

CONCLUSIONS

Taken together, these data suggest that TRT after long-term hypogonadism can exacerbate functional recovery after focal cerebral ischemia, but in the absence of injury can enhance cognition. Both of these effects are modulated by oxidative stress levels.

Systemic effects of the hormonal treatment of male hypogonadism with preliminary indications for the management of COVID-19 patients

Male hypogonadism, defined as an inadequate production of testosterone (T), is associated with a greater morbidity and mortality. Epidemiological studies identified T deficiency as a risk factor for cardiovascular disease. Also, low serum T levels impact on glucose homeostasis through a worse glucose uptake, utilization, and disposal, and the general negative impact on metabolism. The aim of this review is to provide a comprehensive and updated overview of the effects of T replacement therapy on metabolic and cardiovascular systems and prostate tissue in patients with hypogonadism, including molecular mechanisms through which T exerts its actions. Furthermore, recent findings on novel coronavirus disease (COVID-19) epidemiology have shown a greater mortality in male compared with female patients and a role of T in promoting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection of the host cells has been demonstrated. Hence, the secondary aim of this review is to provide preliminary indications on the management in patients with COVID-19.

Sleep restriction and testosterone concentrations in young healthy males: randomized controlled studies of acute and chronic short sleep

OBJECTIVE

Low testosterone in men increases the risk for various disorders. Severe sleep restriction (SR) may reduce testosterone, but the effects of long-term short sleep are unknown. This study tested the effects of SR on circulating testosterone in healthy young men.

DESIGN

Randomized controlled studies of SR vs habitual sleep (HS) in inpatient (study 1, n=14) and outpatient (study 2, n=13) settings.

METHODS

Study 1 involved severe, acute SR (4 hours time in bed [TIB]) vs HS (9 hours TIB) for 5 nights; study 2 consisted of mild, long-term SR (HS 1.5 hours of sleep/night) vs HS for 6 weeks. Plasma testosterone levels were measured at baseline and end point (study 1) or baseline, week 3, and week 6 (study 2) of each phase. Linear model analyses to assess the effects of SR on testosterone were performed separately for each study.

RESULTS

Study 1: There were no significant sleep-time interaction on testosterone concentrations (change in testosterone levels during HS = 22.86 ± 163.79 ng/dL; SR = 43.73 ± 159.96 ng/dL, P = .41) and no main effect of sleep duration (P = .13). Study 2: There were a trend for a sleep-time interaction (P = .067) and a main effect of sleep on testosterone concentrations from 6 weeks of SR (P = .0046). Testosterone concentrations were slightly lower but increased over time with SR relative to HS.

CONCLUSIONS

Sleep restriction does not adversely affect plasma testosterone levels in healthy young men. Given prior contradicting evidence, confirmatory studies should be done to ascertain the influence of sleep duration and quality on testosterone concentrations in men throughout life.

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.

Cardiovascular Safety and Possible Benefit of a 5-Alpha Reductase Inhibitor among Benign Prostatic Hyperplasia Patients, A Nationally Representative Cohort of Korean Men

Several studies suggest that 5-alpha reductase inhibitors (5ARIs) may be associated with elevated risk of cardiovascular disease (CVD). We investigated the association of 5ARI exposure and CVD incidence using the National Health Insurance Service-Health Screening Cohort, a nationally representative population-based sample of Koreans. We calculated the 4-year cumulative exposure to 5ARI for 215,003 men without prior 5ARI use. Participants were followed from January 1st, 2008 to December 31st, 2015. A subcohort of newly diagnosed benign prostatic hyperplasia (BPH) patients during 2004–2010 was also analyzed. The primary study outcome was CVD and secondary outcomes were myocardial infarction (MI) or stroke. Hazard ratios (HRs) were estimated using Cox proportional hazards models adjusted for conventional risk factors. In both the main cohort and BPH subcohort, the use of any 5ARI did not increase the risk of cardiovascular disease (HR = 1.06; 95% CI = 0.91–1.23; HR = 0.95; 95% CI = 0.88–1.03; respectively). Furthermore, as an unexpected finding, a dose-analysis among the BPH subcohort showed that the highest tertile of 5ARI exposure reduced the risk of CVD (HR = 0.82; 95% CI = 0.72–0.92; p-trend = 0.001), MI (HR = 0.69; 95% CI = 0.50–0.95), and stroke (HR = 0.84; 95% CI = 0.72–0.98) compared to non-users. Among men and BPH patients, 5ARI did not increase the risk of CVD. Among BPH patients, 5ARI use may reduce the risk CVD.

The Association of Serum Testosterone Levels With Recurrence and Mortality After Acute Ischemic Stroke in Males

The current study aimed to investigate whether low testosterone predicted the recurrence and clinical outcomes after acute ischemic stroke (AIS) in males. From June 2015 through August 2017, the study prospectively enrolled 110 male AIS patients. All received detailed evaluations at admission and were followed for at least 1 year. The cumulative incidence, overall survival, length of hospital stay, and the percentage of previous stroke were compared between subjects with testosterone <440 ng/dl and >440 ng/dl. The median age was 62 years (range, 35–93 years). The median serum testosterone at admission was 438 [203] ng/dl (range, 44–816 ng/dl); 55 patients (50%) had testosterone <440 ng/dl and were considered as low testosterone. The median follow-up was 23 months. During the period, 12 recurrences and 10 deaths occurred. The 1-year and 3-year cumulative recurrence rate were 8.3% and 11.9%, respectively; the 1-year and 3-year overall survival were 96.3% and 84.6%, respectively. The cumulative recurrence rates were similar between the two testosterone groups (log-rank test, p = .88). Low testosterone was associated with poor survival with marginal significance (log-rank test, p = .079). Men with low testosterone had a higher percentage of previous stroke (29.1% versus 12.7%, p = .035). The mean lengths of hospital stay were similar between the two testosterone groups (16.6 ± 15.8 days versus 14.0 ± 10.6, p = .31). Total testosterone at admission fails to predict stroke recurrence. However, men with low testosterone at admission are more likely to have previous stroke and may have a higher all-cause mortality rate after AIS.

Testosterone and its metabolites: differential associations with cardiovascular and cerebrovascular events in men

As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly contributing factors to clinical manifestations of cardiovascular disease in the increasing demographic of aging men, has attracted considerable interest. This review focuses on observational studies of endogenous androgens, namely circulating testosterone and dihydrotestosterone, which have examined their associations with cardiovascular events such as myocardial infarction and stroke. Studies which have examined the associations of endogenous estrogens, namely circulating estradiol, with these outcomes are also discussed. In large prospective cohort studies of predominantly middle-aged and older men, lower circulating testosterone consistently predicts higher incidence of cardiovascular events. Of note, both lower circulating testosterone and lower dihydrotestosterone are associated with higher incidence of stroke. These associations are less apparent when myocardial infarction is considered as the outcome. Results for estradiol are inconsistent. Lower circulating testosterone has been shown to predict higher cardiovascular disease-related mortality, as has lower circulating dihydrotestosterone. It is possible that the relationship of circulating androgens to cardiovascular events or mortality outcomes may be U-shaped rather than linear, with an optimal range defining men at lowest risk. Epidemiological studies are observational in nature and do not prove causality. Associations observed in studies of endogenous androgens need not necessarily translate into similar effects of exogenous androgens. Rigorous randomized controlled trials are needed to clarify the effects of testosterone treatment on cardiovascular risk in men.

Potential relation between soluble growth differentiation factor-15 and testosterone deficiency in male patients with coronary artery disease

Background

There is a mutual interaction between inflammation and endocrine disorders in the development of coronary artery disease (CAD). Growth differentiation factor-15 (GDF-15) is associated with CAD, and the effects of testosterone on CAD as reported in literature have been considered as anti-atherosclerotic. The present study aimed to examine the possible association between serum GDF-15 and testosterone in male CAD patients.

Methods

GDF-15 and testosterone concentrations were determined in blood samples of 426 male patients with CAD and 220 male controls. Serum concentrations of hs-CRP, and other baseline characteristics were also measured.

Results

Serum levels of GDF-15 were higher in CAD patients when compared to controls, and testosterone concentrations were lower (p < 0.001). Patients with low testosterone levels had higher concentrations of GDF-15 (p < 0.001). In stratified analyses, inverse relations between GDF-15 levels and testosterone were noted for almost all strata, stratified by categories of hs-CRP, leukocytes, neutrophils, neutrophil to lymphocyte ratio, glucose, HDL-c, and LDL-c, and whether had hypertension, diabetes, and underwent percutaneous coronary intervention (PCI). Furthermore, in the linear regression models with bootstrap resampling with 1000 replications, high GDF-15 levels were independently associated with testosterone deficiency in male patients with CAD.

Conclusions

In male patients with CAD, high GDF-15 levels were associated with testosterone deficiency. These results support that upregulation of GDF-15 in the presence of low testosterone levels during CAD progression is a potential mechanism by which GDF-15 affects CAD.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0823-3) contains supplementary material, which is available to authorized users.

Simultaneous measurement of 18 steroids in human and mouse serum by liquid chromatography-mass spectrometry without derivatization to profile the classical and alternate pathways of androgen synthesis and metabolism

BACKGROUND

The recently identified alternate, or backdoor, pathway of DHT synthesis provides important novel information on androgen biosynthesis beyond the classical pathway. We report a rapid and versatile liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to simultaneously and accurately quantify key steroids in human or mouse serum involved in either the classical or backdoor androgen synthesis pathways.

METHODS

Serum (200 µL) fortified with isotopically labelled internal standards underwent liquid-liquid extraction (LLE) with MTBE and extracts were analysed on a LC-MS/MS. The targeted steroids for quantification were testosterone (T), dihydrotestosterone (DHT), 5α-androstane-3α,17β-diol (3α diol), 5α-androstane-3β,17β-diol (3β diol), dehydroepiandrosterone (DHEA), androstenedione (A4), androsterone (AD), estradiol (E2), estrone (E1), progesterone (P4), pregnenolone (P5), androstenediol (Adiol), 17-hydroxyprogesterone (17-OHP4) and 17-hydroxypregnenolone (17-OHP5), corticosterone (B), cortisol (F), allopregnanolone (Allo-P5) and dihydroprogesterone (DHP).

RESULTS

The limits of quantification (LOQ) were 5 pg/mL for E2 and E1, 25 pg/mL for T, 50 pg/mL for A4 and 0.10 ng/mL for DHT, 17OHP5, P4, P5, AD, Adiol, DHEA, AlloP5 and 0.20 ng/mL for 17OHP4, 3α diol, 3β diol, DHP, 0.25 ng/mL for B and 1 ng/mL for F. Accuracy, precision, reproducibility and recovery were within acceptable limits for bioanalytical method validation. The method is illustrated in human and mouse, male and female serum.

CONCLUSIONS

The presented method is sufficiently sensitive, specific and reproducible to meet the quality criteria for routine laboratory application for accurate quantitation of 18 steroid concentrations in male and female serum from humans or mice for the purpose of profiling androgen synthesis and metabolism pathways.

Testosterone induced downregulation of migration and proliferation in human Umbilical Vein Endothelial Cells by Androgen Receptor dependent and independent mechanisms

Recent research has emphasized the potential unfavorable effects of declining testosterone (T) levels in men and the putative beneficial effect of androgen therapy in select women. Some controversy surrounding the mechanism of action and the effects of T on endothelium remains. In this study, we evaluated the mechanism of T action on pooled primary Human Umbilical Vein Endothelial Cells (HUVEC) of mixed gender by focusing on two important processes, proliferation and migration. In our in vitro model system, we found that only the supra-physiological dose of T affected these two processes irrespective of the ratio of male to female cells in the pools. At a concentration of 1 μM, T downregulated the proliferation of HUVEC by inducing arrest in the G1 cell cycle phase in an Androgen Receptor (AR)-independent manner. We show that treatment with 1 μM T also induced downregulation of HUVEC migration. This process was AR-dependent and was associated with persistent phosphorylation of ezrin, radixin and moesin. Regardless of the mechanism of action, the treatment of HUVEC with both supra- and physiological doses of T was associated with posttranscriptional stabilization of the AR upon ligand binding.

Testosterone treatment in older men: clinical implications and unresolved questions from the Testosterone Trials

A decrease in the concentration of circulating testosterone in many older men is a biomarker and possibly a rectifiable contributing factor to ill health. Low circulating testosterone concentration has been associated with cardiovascular disease, reduced cognition, fracture risk, and anaemia. However, randomised placebo-controlled trials are essential to clarify the benefits and possible risks of testosterone treatment in men without hypothalamic, pituitary, or testicular disease. The Testosterone Trials (T-Trials) were a coordinated set of trials that, following a screening-to-enrolment ratio of 65:1, randomly assigned 790 men aged 65 years or older who had a baseline testosterone concentration of less than 9·54 nmol/L and symptoms consistent with hypogonadism, but no recognisable hypothalamic-pituitary-testicular axis pathology, to daily transdermal testosterone or placebo for 12 months. In the main trial, testosterone treatment resulted in a modest benefit for sexual function, whereas the other primary outcomes of vitality and physical function were not met. Data from concomitant substudies raised a possible concern over changes in coronary plaque volume, showed a neutral effect on memory and other cognitive functions, and revealed improvements in volumetric bone mineral density and anaemia. Although insufficient to alter the existing clinical equipoise, the T-Trials provided substantial new data on organ-specific outcomes for testosterone treatment in older men. Further clinical trials are necessary to determine whether testosterone treatment will translate into patient-valued health outcomes and to clarify effects on the cardiovascular system.

Role of androgens in energy metabolism affecting on body composition, metabolic syndrome, type 2 diabetes, cardiovascular disease, and longevity: lessons from a meta-analysis and rodent studies

Testosterone is a sex hormone produced by testicular Leydig cells in males. Blood testosterone concentrations increase at three time-periods in male life-fetal, neonatal (which can be separated into newborn and infant periods), and pubertal stages. After peaking in the early 20s, the blood bioactive testosterone level declines by 1-2% each year. It is increasingly apparent that a low testosterone level impairs general physical and mental health in men. Here, this review summarizes recent systematic reviews and meta-analyses of epidemiological studies in males (including cross-sectional, longitudinal, and androgen deprivation studies, and randomized controlled testosterone replacement trials) in relation to testosterone and obesity,  body composition, metabolic syndrome, type 2 diabetes, cardiovascular disease, and longevity. Furthermore, underlying mechanisms are discussed using data from rodent studies involving castration or androgen receptor knockout. This review provides an update understanding of the role of testosterone in energy metabolism. Abbreviations AR: androgen receptor; CV: cardiovascular; FDA: US Food and Drug Administration; HFD: high-fat diet; KO: knockout; MetS: metabolic syndrome; RCT: randomized controlled trial; SHBG: sex hormone binding globulin; SRMA: systematic review and meta-analysis; TRT: testosterone replacement therapy; T2DM:type 2 diabetes mellitus.

Serum androgens and risk of atrial fibrillation in older men: The Cardiovascular Health Study

BACKGROUND

Decline in serum androgens is common among older men and has been associated with cardiovascular disease, although its role in risk of atrial fibrillation (AF) has not been well defined.

HYPOTHESIS

Low serum androgens are associated with an increased risk of AF.

METHODS

We examined the prospective associations between testosterone, its more active metabolite dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) with risk of AF among 1019 otherwise healthy men with average age 76.3 ±4.9 years in the Cardiovascular Health Study.

RESULTS

After median follow-up of 9.5 years, 304 (30%) men developed AF. We detected a nonlinear association with risk of incident AF in both free and total DHT, in which subjects with the lowest levels had a higher risk of incident AF. After adjustment for demographics, clinical risk factors, left atrial diameter, and serum NT-proBNP levels, men with free DHT <0.16 ng/dL were at increased risk compared with men with higher levels (hazard ratio: 1.48, 95% confidence interval: 1.01-2.17, P <0.05). Sensitivity analyses confirmed that the increased risk was not cutpoint-specific, with a significant association noted up to cutpoints <~0.2 ng/dL. We also detected a complex nonlinear association between SHBG and incident AF, in which subjects in the middle quintile (52.9-65.3 nmol/L) had increased risk.

CONCLUSIONS

Among older men, low free DHT is associated with an increased risk of incident AF. Further studies are needed to explore mechanisms for this association.

What does the research say about androgen use and cerebrovascular events?

Many studies have investigated the benefits of androgen therapy and neurosteroids in aging men, while concerns remain about the potential associations of exogenous steroids and incidents of cerebrovascular events and ischemic stroke (IS). Testosterone is neuroprotective, neurotrophic and a potent stimulator of neuroplasticity. These benefits are mediated primarily through conversion of a small amount of testosterone to estradiol by the catalytic activity of estrogen synthetase (aromatase cytochrome P450 enzyme). New studies suggest that abnormal serum levels of the nonaromatized potent metabolite of testosterone, either high or low dihydrotestosterone (DHT), is a risk factor for stroke. Associations between pharmacologic androgen use and the incidence of IS are questionable, because a significant portion of testosterone is converted to DHT. There is also insufficient evidence to reject a causal relationship between the pro-testosterone adrenal androgens and incidence of IS. Moreover, vascular intima-media thickness, which is a predictor of stroke and myocardial symptoms, has correlations with sex hormones. Current diagnostic and treatment criteria for androgen therapy for cerebrovascular complications are unclear. Confounding variables, including genetic and metabolic alterations of the key enzymes of steroidogenesis, ought to be considered. Information extracted from pharmacogenetic testing may aid in expounding the protective-destructive properties of neurosteroids, as well as the prognosis of androgen therapy, in particular their cerebrovascular outcomes. This investigative review article addresses relevant findings of the clinical and experimental investigations of androgen therapy, emphasizes the significance of genetic testing of androgen responsiveness towards individualized therapy in post-IS injuries as well as identifying pertinent questions.

Cardiovascular benefits and risks of testosterone replacement therapy in older men with low testosterone

Many studies have shown that low testosterone (T) levels have been associated with increased risk for cardiovascular (CV) events, type 2 diabetes mellitus (T2DM), and strokes. In contrast, many other studies have demonstrated that normal T levels or the normalization of low T levels with testosterone replacement therapy (TRT) is associated with decreased incidence of CV events, T2DM, and strokes, besides improving sexual function and the quality of life. However, recent studies have indicated that TRT could lead to increased incidence of CV events and strokes. These latter studies have created a great controversy among physicians regarding these findings, who question the validity of their results. In order to get a better perspective on the current status of TRT in hypogonadal men, a focused Medline and EMBASE search of the English language literature was conducted between 2010 and 2017 using the terms hypogonadism, low Testosterone, cardiovascular disease, testosterone replacement therapy, benefits, risks, older men, mechanism of action, and 58 papers with pertinent information were selected and 48 papers were rejected. The selected papers will be discussed in this review. In conclusion, based on the current status of TRT, the majority of studies indicate that TRT is safe and is associated with prevention of CVD and strokes in hypogonadal men. However, the evidence is not uniform and the therefore, decision to administer TRT should be discussed with the patient till more definitive information becomes available.

Individual testosterone decline and future mortality risk in men

OBJECTIVE

Male aging is characterized by a decline in testosterone (TS) levels with a substantial variability between subjects. However, it is unclear whether differences in age-related changes in TS are associated with general health. We investigated associations between mortality and intra-individual changes in serum levels of total TS, SHBG, free TS and LH during a ten-year period with up to 18 years of registry follow-up.

DESIGN

1167 men aged 30-60 years participating in the Danish Monitoring Trends and Determinants of Cardiovascular Disease (MONICA1) study and who had a follow-up examination ten years later (MONICA10) were included. From MONICA10, the men were followed up to 18 years (mean: 15.2 years) based on the information from national mortality registries via their unique personal ID numbers.

METHODS

Cox proportional hazard models were used to investigate the association between intra-individual hormone changes and all-cause, CVD and cancer mortalities.

RESULTS

A total of 421 men (36.1%) died during the follow-up period. Men with most pronounced decline in total TS (<10th percentile) had a higher all-cause mortality risk compared to men within the 10th to 90th percentile (hazard ratio (HR): 1.60; 95% confidence interval (CI): 1.08-2.36). No consistent associations were seen in cause-specific mortality analyses.

CONCLUSION

Our study showed that higher mortality rates were seen among the men who had the most pronounced age-related decline in TS, independent of their baseline TS levels.

Dose-response effects of sex hormone concentrations on body composition and adipokines in medically castrated healthy men administered graded doses of testosterone gel

OBJECTIVE

Serum sex steroid concentrations may alter body composition and glucose homoeostasis in men in a dose-response manner. We evaluated these end-points in healthy men rendered medically castrate through use of a gonadotrophin-releasing hormone antagonist (acyline) with incremental doses of exogenous testosterone (T) gel.

DESIGN

Subjects (n=6-9 per group) were randomly assigned to injections of acyline every 2 weeks plus transdermal T gel (1.25 g, 2.5 g, 5.0 g, 10 g or 15 g) daily or double placebo (injections and gel) for 12 weeks.

PATIENTS

Healthy men, ages 25-55 years, with normal serum total T concentrations.

MEASUREMENTS

Serum T, dihydrotestosterone (DHT) and oestradiol (E2) were measured at baseline and every 2 weeks. Body composition was analysed by dual-energy X-ray absorptiometry at baseline and week 12. Fasting serum adiponectin, leptin, glucose and insulin concentrations were measured at baseline and week 10.

RESULTS

Forty-eight men completed the study. A significant treatment effect was observed for change in lean mass (ANOVAP=.01) but not fat mass (P=.14). Lean mass increased in the 15 g T group relative to all lower dose groups, except the 10 g T group. When all subjects were analysed together, changes in lean mass correlated directly and changes in fat mass correlated inversely with serum T, E2 and DHT. No changes were noted in serum glucose, insulin or adipokine levels.

CONCLUSIONS

In healthy men, higher serum concentrations of T, DHT and E2 were associated with greater increases in lean mass and decreases in fat mass but not with changes in serum glucose, insulin or adipokines.

Dihydrotestosterone: Biochemistry, Physiology, and Clinical Implications of Elevated Blood Levels

Benefits associated with lowered serum DHT levels after 5α-reductase inhibitor (5AR-I) therapy in men have contributed to a misconception that circulating DHT levels are an important stimulus for androgenic action in target tissues (e.g., prostate). Yet evidence from clinical studies indicates that intracellular concentrations of androgens (particularly in androgen-sensitive tissues) are essentially independent of circulating levels. To assess the clinical significance of modest elevations in serum DHT and the DHT/testosterone (T) ratio observed in response to common T replacement therapy, a comprehensive review of the published literature was performed to identify relevant data. Although the primary focus of this review is about DHT in men, we also provide a brief overview of DHT in women. The available published data are limited by the lack of large, well-controlled studies of long duration that are sufficiently powered to expose subtle safety signals. Nonetheless, the preponderance of available clinical data indicates that modest elevations in circulating levels of DHT in response to androgen therapy should not be of concern in clinical practice. Elevated DHT has not been associated with increased risk of prostate disease (e.g., cancer or benign hyperplasia) nor does it appear to have any systemic effects on cardiovascular disease safety parameters (including increased risk of polycythemia) beyond those commonly observed with available T preparations. Well-controlled, long-term studies of transdermal DHT preparations have failed to identify safety signals unique to markedly elevated circulating DHT concentrations or signals materially different from T.

Testosterone replacement therapy and the heart: friend, foe or bystander?

The role of testosterone therapy (TTh) in cardiovascular disease (CVD) outcomes is still controversial, and it seems will remain inconclusive for the moment. An extensive body of literature has investigated the association of endogenous testosterone and use of TTh with CVD events including several meta-analyses. In some instances, a number of studies reported beneficial effects of TTh on CVD events and in other instances the body of literature reported detrimental effects or no effects at all. Yet, no review article has scrutinized this body of literature using the magnitude of associations and statistical significance reported from this relationship. We critically reviewed the previous and emerging body of literature that investigated the association of endogenous testosterone and use of TTh with CVD events (only fatal and nonfatal). These studies were divided into three groups, “beneficial (friendly use)”, “detrimental (foe)” and “no effects at all (bystander)”, based on their magnitude of associations and statistical significance from original research studies and meta-analyses of epidemiological studies and of randomized controlled trials (RCT’s). In this review article, the studies reporting a significant association of high levels of testosterone with a reduced risk of CVD events in original prospective studies and meta-analyses of cross-sectional and prospective studies seems to be more consistent. However, the number of meta-analyses of RCT’s does not provide a clear picture after we divided it into the beneficial, detrimental or no effects all groups using their magnitudes of association and statistical significance. From this review, we suggest that we need a study or number of studies that have the adequate power, epidemiological, and clinical data to provide a definitive conclusion on whether the effect of TTh on the natural history of CVD is real or not.

The Cardiovascular Safety of Dutasteride

PURPOSE

Randomized controlled trials suggest an increased risk of heart failure with dutasteride, which inhibits both the type 1 and type 2 isoforms of 5α-reductase. In contrast, no such association has been suggested for finasteride, which selectively inhibits the type 2 isoform. We investigated the risk of cardiovascular events among patients receiving dutasteride relative to finasteride.

MATERIALS AND METHODS

We performed a population based cohort study of Ontario men 66 years old or older who commenced treatment with dutasteride or finasteride between October 1, 2005 and March 31, 2015. For each individual treated with dutasteride, we identified 1 treated with finasteride, matching on a propensity score and calendar quarter of treatment initiation to account for temporal changes in prescribing. The primary outcome was hospitalization for heart failure. Secondary analyses were done to examine acute myocardial infarction and stroke. Cox proportional hazards regression was used to adjust for differences between groups.

RESULTS

We studied 36,311 men who commenced dutasteride and 36,311 treated with finasteride. In the primary analysis, we found no difference in the risk of heart failure among patients receiving dutasteride relative to those receiving finasteride (adjusted HR 0.98, 95% CI 0.88-1.08). Similarly, we found no difference in the risk of acute myocardial infarction (HR 0.94, 95% CI 0.82-1.08) or stroke (HR 1.03, 95% CI 0.88-1.20).

CONCLUSIONS

In this population based cohort study of more than 72,000 older men, dutasteride was not associated with an increased risk of cardiovascular events relative to finasteride.

The Current Understanding of Sarcopenia: Emerging Tools and Interventional Possibilities

The purpose of this review is to provide health practitioners and physicians the most current state of the research on sarcopenia, its consequences, and to offer a summary of consensus guidelines for identification based on the most recent and compelling investigations and analyses. To accomplish this, the causes and consequences of sarcopenia will be described, and definitions and screening methods are updated. Importantly, interventional recommendations for sarcopenia will be discussed with a special emphasis on the effects of resistance training on sarcopenia-related outcomes. Furthermore, due to the increasing usage of hormone treatment as a strategy to combat sarcopenia, special consideration on the effects of hormone changes with aging and as interventions will be briefly reviewed.

An update on the role of testosterone replacement therapy in the management of hypogonadism

While US testosterone prescriptions have tripled in the last decade with lower trends in Europe, debate continues over the risks, benefits and appropriate use of testosterone replacement therapy (TRT). Some authors blame advertising and the availability of more convenient formulations whilst other have pointed out that the routine testing of men with erectile dysfunction (a significant marker of cardiovascular risk) and those with diabetes would inevitably increase the diagnosis of hypogonadism and lead to an increase in totally appropriate prescribing. They commented that this was merely an appropriate correction of previous underdiagnosis and undertreatment by adherence to evidence-based guidelines. Urologists and primary care physicians are the most frequent initiators of TRT, usually for erectile dysfunction. Benefits are clearly established for sexual function, increase in lean muscle mass and strength, mood and cognitive function, with possible reduction in frailty and osteoporosis. There remains no evidence that TRT is associated with increased risk of prostate cancer or symptomatic benign prostatic hyperplasia, yet the decision to initiate and continue therapy is often decided by urologists. The cardiovascular issues associated with TRT have been clarified by recent studies showing clearly that therapy associated with clear rise in testosterone levels are associated with reduced mortality. Studies reporting to show increased risk have been subject to flawed designs with inadequate baseline diagnosis and follow-up testing. Effectively they have compared nontreated patients with undertreated or on-compliant subjects involving a range of different therapy regimens. Recent evidence suggests long acting injections may be associated with decreased cardiovascular risk but the transdermal route may be associated with potentially relatively greater risk because of conversion to dihydrotestosterone by the effect of 5α reductase in skin. The multiple effects of TRT may add up to a considerable benefit to the patient that might be underestimated by the physician primarily concerned with his own specialty. This paper will attempt to identify who should be treated, and how they should be treated safely to achieve best outcomes, based on a comprehensive MEDLINE and EMBASE and Cochrane searches on hypogonadism, TRT and cardiovascular safety from May 2005 to May 2015. This revealed 1714 papers with 52 clinical trials and 32 placebo-controlled randomized, controlled trials.

A review of the relationships between endogenous sex steroids and incident ischemic stroke and coronary heart disease events

For decades, it has been recognized that men have a higher age-adjusted risk of ischemic cardiovascular (CVD) events compared to women, thus generating hypotheses that sex steroids contribute to CVD risk. Potential mechanisms include genomic and non-genomic effects of sex steroids as well as mediation through classic CVD risk factors and obesity. However, results from randomized studies suggest that sex steroid supplementation in men and women do not result in improved CVD outcomes and may increase CVD risk. In contrast, prospective observations from endogenous sex steroid studies, i.e. among participants not using sex steroids, have suggested the opposite relationship. We reviewed the findings of prospective observational studies in men (17 studies) and women (8 studies) that examined endogenous sex steroids and CVD risk. These studies suggested a lack of association or that lower levels of testosterone or dihydrotestosterone are associated with higher CVD risk in both men and women. Higher, rather than lower, estradiol levels were associated with higher CVD risk in women. There were several significant gaps in the literature. First, it is unclear whether more sensitive measures of sex steroid levels might detect significant differences. Second, there are few prospective studies in women. Similarly, no studies report outcomes for high-risk groups such as African-Americans and Hispanics. Finally, few studies report upon ischemic coronary disease as opposed to ischemic stroke separately, although relationships between sex steroids and CVD may vary by vascular bed. Future investigations need to examine high risk groups and to distinguish between subtypes of CVD.

Cardiovascular effects of hormone therapy for prostate cancer

Androgen deprivation therapy (ADT) has been the mainstay of treatment for advanced prostate cancer for decades, and has been shown to control disease and improve symptoms. In addition, for men with high-risk localized or locally advanced prostate cancer, short-course ADT in combination with radiotherapy improves survival. There is evidence that ADT increases cardiovascular risk, particularly in men with preexisting cardiovascular disease. This increased risk may apply even with short-course ADT. In an individual patient, the benefits of ADT should be balanced against the risk, and patients who require ADT should have risk factors for cardiovascular disease optimized. There is some evidence to suggest that more contemporary methods of delivering ADT may reduce cardiovascular risk.

Injection of testosterone may be safer and more effective than transdermal administration for combating loss of muscle and bone in older men

The value of testosterone replacement therapy (TRT) for older men is currently a topic of intense debate. While US testosterone prescriptions have tripled in the past decade (9), debate continues over the risks and benefits of TRT. TRT is currently prescribed for older men with either low serum testosterone (T) or low T plus accompanying symptoms of hypogonadism. The normal range for serum testosterone is 300 to 1,000 ng/dl. Serum T ≤ 300 ng/dl is considered to be low, and T ≤ 250 is considered to be frank hypogonadism. Most experts support TRT for older men with frank hypogonadism and symptoms. Treatment for men who simply have low T remains somewhat controversial. TRT is most frequently administered by intramuscular (im) injection of long-acting T esters or transdermally via patch or gel preparations and infrequently via oral administration. TRT produces a number of established benefits in hypogonadal men, including increased muscle mass and strength, decreased fat mass, increased bone mineral density, and improved sexual function, and in some cases those benefits are dose dependent. For example, doses of TRT administered by im injection are typically higher than those administered transdermally, which results in greater musculoskeletal benefits. TRT also produces known risks including development of polycythemia (Hct > 50) in 6% of those treated, decrease in HDL, breast tenderness and enlargement, prostate enlargement, increases in serum PSA, and prostate-related events and may cause suppression of the hypothalamic-pituitary-gonadal axis. Importantly, TRT does not increase the risk of prostate cancer. Putative risks include edema and worsening of sleep apnea. Several recent reports have also indicated that TRT may produce cardiovascular (CV) risks, while others report no risk or even benefit. To address the potential CV risks of TRT, we have recently reported via meta-analysis that oral TRT increases CV risk and suggested that the CV risk profile for im TRT may be better than that for oral or transdermal TRT.

Testosterone and cardiovascular disease risk

PURPOSE OF REVIEW

Ageing is accompanied by a reduction in circulating testosterone and progressive accumulation of medical morbidities. There is an intense debate whether low testosterone contributes to ill-health as opposed to being a biomarker for its presence. Prescriptions for testosterone are rising on a background of concern over potential adverse effects. This review examines evidence relating androgens to cardiovascular risk in older men.

RECENT FINDINGS

Observational studies show lower risk of cardiovascular events in older men with higher testosterone, and lower mortality from ischaemic heart disease in men with higher concentrations of its more potent androgenic metabolite dihydrotestosterone. However, randomized controlled trials of testosterone supplementation have been underpowered for the outcome of cardiovascular events. Recent meta-analyses have reached contrasting conclusions regarding cardiovascular adverse events associated with testosterone therapy. Retrospective studies of prescription databases have produced controversial and conflicting results.

SUMMARY

Additional randomized controlled trials are required to clarify the role of testosterone supplementation in older men in the absence of pituitary or gonadal disease. Pending such studies, testosterone therapy should be considered in androgen-deficient men, with evaluation of potential benefits and risks.

The value of middle phalangeal hair as an anthropometric marker: A review of the literature

Middle phalangeal hair (MPH) is a trait frequently examined in anthropological studies throughout the 20th century. MPH is found on the back of the middle segment of the fingers, excluding the thumb. Typically, researchers examined the presence and absence of hair in various populations, and described it in terms of age, ancestry, and sex. Recently MPH has been examined as a potential anthropometric indicator of: androgen levels, androgen-related side effects in women, gene homozygosity, and disease resistance. Given the potential value of this marker, the present paper provides a comprehensive overview of MPH and its associated characteristics (i.e., ethnicity, sex, age, and hormonal variations) and presents new data on the reliability of MPH assessment. Findings suggest that ethnicity, sex, and age need to be controlled in any studies examining MPH and its relationship with other variables. Two measures of MPH (i.e., presence/absence of MPH and actual hair count) are both acceptable to use in MPH assessment; and the use of a hand lens to examine MPH provides high reliability when MPH is assessed by expert raters. However, researchers should avoid participant self-assessment. Future avenues for research are suggested (e.g., measurement issues and studies on hormonal correlates in women). MPH could be useful in research or for clinical purposes as a possible non-invasive indicator of hormone levels or hormonal sensitivity, or of predisposition toward androgen-related or gene-homozygosity-related health issues or behaviors.

Review of health risks of low testosterone and testosterone administration

Hypogonadism is prevalent in older men and testosterone replacement therapy (TRT) for older hypogonadal men is a promising therapy. However, a number of important clinical concerns over TRT safety remain unsolved due to a lack of large-scale randomized clinical trials directly comparing the health risks of untreated hypogonadism vs long-term use of TRT. Meta-analyses of clinical trials of TRT as of 2010 have identified three major adverse events resulting from TRT: polycythemia, an increase in prostate-related events, and a slight reduction in serum high-density lipoprotein cholesterol. There are other purported health risks but their incidence can be neither confirmed nor denied based on the small number of subjects that have been studied to date. Furthermore, subsequent literature is equivocal with regard to the safety and utility of TRT and this topic has been subject to contentious debate. Since January 2014, the United States Food and Drug Administration has released two official announcements regarding the safety of TRT and clinical monitoring the risks in TRT users. Additionally, the health risks related to the clinical presentation of low or declining testosterone levels not been resolved in the current literature. Because TRT is prescribed in the context of putative risks resulting from reduced testosterone levels, we reviewed the epidemiology and reported risks of low testosterone levels. We also highlight the current information about TRT utilization, the risks most often claimed to be associated with TRT, and current or emerging alternatives to TRT.

Cardiovascular risks and elevation of serum DHT vary by route of testosterone administration: a systematic review and meta-analysis

BACKGROUND

Potential cardiovascular (CV) risks of testosterone replacement therapy (TRT) are currently a topic of intense interest. However, no studies have addressed CV risk as a function of the route of administration of TRT.

METHODS

Two meta-analyses were conducted, one of CV adverse events (AEs) in 35 randomized controlled trials (RCTs) of TRT lasting 12 weeks or more, and one of 32 studies reporting the effect of TRT on serum testosterone and dihydrotestosterone (DHT).

RESULTS

CV risks of TRT: Of 2,313 studies identified, 35 were eligible and included 3,703 mostly older men who experienced 218 CV-related AEs. No significant risk for CV AEs was present when all TRT administration routes were grouped (relative risk (RR) = 1.28, 95% confidence interval (CI): 0.76 to 2.13, P = 0.34). When analyzed separately, oral TRT produced significant CV risk (RR = 2.20, 95% CI: 1.45 to 3.55, P = 0.015), while neither intramuscular (RR = 0.66, 95% CI: 0.28 to 1.56, P = 0.32) nor transdermal (gel or patch) TRT (RR = 1.27, 95% CI: 0.62 to 2.62, P = 0.48) significantly altered CV risk. Serum testosterone/DHT following TRT: Of 419 studies identified, 32 were eligible which included 1,152 men receiving TRT. No significant difference in the elevation of serum testosterone was present between intramuscular or transdermal TRT. However, transdermal TRT elevated serum DHT (5.46-fold, 95% CI: 4.51 to 6.60) to a greater magnitude than intramuscular TRT (2.20-fold, 95% CI: 1.74 to 2.77).

CONCLUSIONS

Oral TRT produces significant CV risk. While no significant effects on CV risk were observed with either injected or transdermal TRT, the point estimates suggest that further research is needed to establish whether administration by these routes is protective or detrimental, respectively. Differences in the degree to which serum DHT is elevated may underlie the varying CV risk by TRT administration route, as elevated serum dihydrotestosterone has been shown to be associated with CV risk in observational studies.