Association Between Endogenous Testosterone and Cerebrovascular Disease in the ARIC Study (Atherosclerosis Risk in Communities)

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.

Do correlates of white matter features differ between older men and women living with human immunodeficiency virus?

OBJECTIVE

Given estrogen's role in human immunodeficiency virus (HIV) disease progression and the higher rates of neurocognitive decline in affected women, the purpose of this study was to assess whether the relationship of white matter features and reproductive hormone levels differed between men versus women (sex as a moderator), controlling for selected cardiometabolic risk factors, HIV-related health indicators, and demographics in an aging population of persons living with HIV (PLWH).

METHODS

Older PLWH (50 y and older; 44 women and 35 men; mean ± SD age, 59.8 ± 0.6 y; 55.7% women; 72.2% non-Hispanic Black) participated in a cross-sectional study involving a fasting blood draw and a demographic survey (visit 1) and a magnetic resonance imaging scan (visit 2) to determine white matter volume and white matter hyperintensity (WMH) volume. Associations between reproductive hormones (follicle-stimulating hormone [FSH], estradiol, testosterone, dehydroepiandrosterone sulfate [DHEA-S]) and white matter features were assessed in linear regression models. Covariates were age, body mass index, hypertension, diabetes, dyslipidemia, current smoking status, CD4 count, and cranial size.

RESULTS

For white matter volume, a sexually dimorphic interaction was seen for DHEA-S (B = 21.23; P = 0.012) and observed for FSH (B = -22.97, P = 0.08) with a trend for significance after controlling for risk factors. In women, higher white matter volume was associated with higher DHEA-S (B = 13.89, P = 0.017) and lower FSH (B = 23.58, P = 0.01). No hormone associations were shown in men for white matter volume. For WMH volume, no significant interaction effects between sex and reproductive hormones were identified. For WMH, sex did not predict associations with reproductive hormones after controlling for risk factors.

CONCLUSIONS

Although sexually dimorphic interactions of reproductive hormones and total white matter volume were demonstrated, our study findings do not support a role for sex-based differences in reproductive hormones as predictive correlates of WMH in a small sample of older PLWH.

Hormonal factors moderate the associations between vascular risk factors and white matter hyperintensities

To examine the moderation effects of hormonal factors on the associations between vascular risk factors and white matter hyperintensities in men and women, separately. White matter hyperintensities were automatically segmented and quantified in the UK Biobank dataset (N = 18,294). Generalised linear models were applied to examine (1) the main effects of vascular and hormonal factors on white matter hyperintensities, and (2) the moderation effects of hormonal factors on the relationship between vascular risk factors and white matter hyperintensities volumes. In men with testosterone levels one standard deviation higher than the mean value, smoking was associated with 27.8% higher white matter hyperintensities volumes in the whole brain. In women with a shorter post-menopause duration (one standard deviation below the mean), diabetes and higher pulse wave velocity were associated with 28.8% and 2.0% more deep white matter hyperintensities, respectively. These findings highlighted the importance of considering hormonal risk factors in the prevention and management of white matter hyperintensities.

Testosterone deficiency and metabolic disturbances in men who fathered a child by use of donated spermatozoa

Dose–response association between level of impairment of semen quality and risk of morbidity or premature death has been reported. Therefore, it can be presumed that men utilizing donated spermatozoa, i.e. patients with non-obstructive azoospermia, are at highest risk for adverse health outcomes. To evaluate the risks of prescription of medications for common metabolic disturbances and testosterone replacement therapy (TRT) among men who father children with donated spermatozoa—who presumably do it due to severe impairment of fertility. We used Swedish nationwide register data on all fathers who had a live-born child between 2007 and 2014 in order to compare men who fathered children with donated spermatozoa to the ones who became fathers by using own gametes. Cox regression analysis was used in order to estimate the post-conception incidence of prescription of medicines for hypertension (HT), diabetes (type 1 and 2), dyslipidaemia (DLE) or TRT. Starting the follow up at time of conception, models were adjusted for age, educational level, and previous cancer treatment. In total 410,119 childbirths were included in the analysis. Among them, for 390 fathers donated spermatozoa were utilized. Fathers to children conceived with donated spermatozoa had higher risk for having TRT prescribed (HR: 18.14; 95%CI: 11.71–28.10; p ≪ 0.001). Same was true for DLE (HR: 2.08; 95%CI: 1.27–3.39; p = 0.003) but not diabetes. Fathers to children conceived by use of donated spermatozoa are at significantly increased risk for testosterone treatment and dyslipidaemia, necessitating stringent follow up and inclusion in prevention programs.

Genetic, Molecular, and Cellular Determinants of Sex-Specific Cardiovascular Traits

Despite the well-known sex dimorphism in cardiovascular disease traits, the exact genetic, molecular, and cellular underpinnings of these differences are not well understood. A growing body of evidence currently points at the links between cardiovascular disease traits and the genome, epigenome, transcriptome, and metabolome. However, the sex-specific differences in these links remain largely unstudied due to challenges in bioinformatic methods, inadequate statistical power, analytic costs, and paucity of valid experimental models. This review article provides an overview of the literature on sex differences in genetic architecture, heritability, epigenetic changes, transcriptomic signatures, and metabolomic profiles in relation to cardiovascular disease traits. We also review the literature on the associations between sex hormones and cardiovascular disease traits and discuss the potential mechanisms underlying these associations, focusing on human studies.

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.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

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 therapy and cardiovascular diseases

Since it was first synthesised in 1935, testosterone (T) has been viewed as the mythical Fountain of Youth, promising rejuvenation, restoring sexual appetites, growing stronger muscles, and quicker thinking. T is endowed with direct effects on myocardial and vascular structure and function, as well as on risk factors for cardiovascular (CV) disease. Indeed, low serum T levels are a risk factor for diabetes, metabolic syndrome, inflammation, and dyslipidaemia. Moreover, many studies have shown that T deficiency per se is an independent risk factor of CV and all-cause mortality. On this background and due to direct-to-patient marketing by drug companies, we have witnessed to the widespread use of T replacement therapy (TT) without clear indications particularly in late-life onset hypogonadism. The current review will dwell upon current evidence and controversies surrounding the role of T in the pathophysiology of CV diseases, the link between circulating T levels and CV risk, and the use of replacing T as a possible adjuvant treatment in specific CV disorders. Specifically, recent findings suggest that heart failure and type 2 diabetes mellitus represent two potential targets of T therapy once that a state of hypogonadism is diagnosed. However, only if ongoing studies solve the CV safety issue the T orchid may eventually 'bloom'.

Testosterone Deficiency, Long-Term Testosterone Therapy, and Inflammation

OBJECTIVES

We aimed to evaluate the association of testosterone deficiency with inflammation and how long-term testosterone therapy affects inflammation biomarkers over time.

METHODS

We conducted a 2-component study. First, we conducted a cross-sectional study using the recently released 2015-2016 National Health and Nutrition Examination Survey (NHANES) data to examine the association between testosterone deficiency and inflammation biomarkers including high sensitivity C-reactive protein (hsCRP), liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the US general population. Then we conducted a longitudinal study to investigate the longitudinal effect of testosterone therapy on inflammation biomarkers and the risk of cardiovascular events, using data from 776 hypogonadal men based on a registry study in Germany with up to 11 years' follow-up.

RESULTS

The adjusted odds ratios (ORs) describing the associations between testosterone deficiency and hsCRP ≥ 3mg/L, ALT > 40U/L, and AST > 40U/L were 1.81 (P-value < 0.001), 1.46 (P-value = 0.009), and 0.99 (P-value = 0.971), respectively. In the control group, CRP, ALT, and AST levels increased by 0.003 (95%CI: -0.001, 0.007) mg/L, 0.157 U/L (95%CI: 0.145, 0.170), and 0.147 (95%CI: 0.136, 0.159) U/L per month, while in the treatment group, CRP, ALT, and AST levels decreased by 0.05 (95%CI: -0.055, -0.046) mg/L, 0.142 U/L (95%CI: -0.154, -0.130), and 0.148 (95%CI: -0.158, -0.137) U/L per month.

CONCLUSION

Testosterone deficiency was associated with an increased level of inflammation; long-term testosterone therapy alleviated inflammation among hypogonadal men, which may contribute to the reduced cardiovascular risk. Future large trials are warranted to confirm our observational study findings.

Association of Serum Testosterone and Luteinizing Hormone With Blood Pressure and Risk of Cardiovascular Disease in Middle-Aged and Elderly Men

Background

The age‐related decline in testosterone levels is thought to be of great importance for male aging and cardiovascular diseases. However, data are controversial on whether abnormal sex hormones are linked to the presence of cardiovascular diseases and it is also uncertain how blood pressure modifies the association between testosterone levels and major cardiovascular diseases.

Methods and Results

This is a multicenter, population‐based, cross‐sectional study of 6296 men conducted between 2013 and 2016. Basic information and clinical symptoms were obtained by questionnaires. Blood pressure and plasma levels of total testosterone, sex hormone–binding globulin, luteinizing hormone, and free testosterone were determined in men in a multistage random, cluster sampling in 6 provinces of China. There were 5786 Chinese men (mean [SD] age 55.0 [10.1] years) included after exclusion criteria were applied; 37.2% (2150) of them were diagnosed with hypertension. Total testosterone, free testosterone, and sex hormone–binding globulin were inversely associated with the prevalence of hypertension. Age >65 years or body mass index ≥24 negatively impacted the inverse correlation between testosterone levels and hypertension, whereas smoking and family history of hypertension strengthened the correlation. In participants with grade 2 hypertension, total testosterone was positively associated with the presence of stroke, and luteinizing hormone was also positively correlated with cardiovascular and cerebrovascular diseases.

Conclusions

Lower total testosterone could be a promising risk marker for prevalent hypertension. Both low and high levels of testosterone are associated with greater cardiovascular risk. Primary hypogonadism may be a risk marker for major cardiovascular diseases in men with severe hypertension.

Recent testosterone drop-off and risk of cardiovascular events

Low baseline testosterone level has been associated with the development of risk factors for cardiovascular disease such as insulin resistance and obesity. In addition to the absolute testosterone level, remarkable changes in testosterone level may have an acute effect on cardiovascular disease development and progression, which has been rarely investigated. In this study, we used a clinical dataset of 376 hypogonadal men whose testosterone levels were measured every six months for up to 11 years from a registry study in Germany, and conducted survival analyses to investigate the effect of testosterone changes since the last visit (time-varying) on the risk of cardiovascular events. Given the potential discrepancies in comorbidity conditions among patients with prior cardiovascular events and those without, all the analyses were stratified by patients' prior cardiovascular event status. We found the effects were not different among patients with prior cardiovascular events and those without. Regardless of patients' prior cardiovascular event status, patients with larger testosterone declines (≥3.12 nmol/L, 90^th percentile) since the last visit were more likely to experience myocardial infarction. In conclusion, recent pronounced testosterone drop-offs may affect the risk of cardiovascular events among hypogonadal men. Future longitudinal studies are needed to confirm our exploratory study findings.

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.

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.

Hypogonadism and its treatment following ischaemic stroke in men with type 2 diabetes mellitus

Premature mortality in Russia is a major socio-economic problem, especially from acute cerebrovascular diseases which constitute 21.4% of the total mortality and is a considerable contributor to chronic disability. Risk of vascular catastrophe is higher in males than females, thought, in part, due to anti-atherosclerotic effects of oestrogens in females whilst an associated age-related deficiency of testosterone is observed in men. Clinical symptoms such as high blood pressure, changes in lipid profile, insulin resistance, obesity, and blood coagulation factors often accompany declining testosterone in males and reduced total testosterone is considered a cardiovascular risk factor. In the present study, the prevalence of hypogonadism in men who had suffered ischaemic stroke was evaluated along with the efficacy of testosterone undecanoate injections (TU) in patients with testosterone deficiency and type-2 diabetes (T2DM) in the acute phase of hemispheric ischaemic stroke. Hypogonadism was present in 66.3% of patients with ischaemic stroke, 50% with T2DM, and 26.3% without T2DM, respectively. TU treatment, at both the 2 and 5-year observation points, demonstrated significant improvements in biochemical, physical, and mental parameters. This supports that testosterone deficiency is a contributing factor in ischaemic events and that long-term testosterone therapy could play an important role in patient recovery.

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.

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 associations of circulating growth differentiation factor-15 with sex hormones in male patients with coronary artery disease

This study aimed to explore the association between growth differentiation factor-15 (GDF-15), a stress-induced factor, and sex hormones in male patients with coronary artery disease (CAD). In this study, we recruited 253 male patients with CAD and 205 male controls. Patients were divided into three groups in accordance with GDF-15 tertiles. Serum levels of GDF-15, testosterone, estradiol and other biochemical variables were measured. Serum levels of GDF-15 were significantly increased and serum testosterone and testosterone/estradiol ratio (T/E2 ratio) were significantly decreased in CAD patients compared with controls. Patients with high GDF-15 levels had lower testosterone (203.97, 95% CI 154.67-328.30 vs. 303.98, 95% CI 246.93-345.66; P = 0.001) and T/E2 ratio (8.82, 95% CI 5.77-11.41 vs. 11.07, 95% CI 7.91-14.32; P = 0.013). Correlation analyses showed that serum GDF-15 levels inversely correlated with testosterone levels (r = -0.339) and T/E2 ratio (r = -0.365) (both P < 0.001). In multivariate regression analyses, the association between GDF-15 and T/E2 ratio was maintained (B=-0.442, 95% CI -99.568 to -6.991, P = 0.015). Furthermore, in vitro studies showed a synergistic effect of testosterone and estradiol on GDF-15 secretion, and demonstrated that testosterone association with estradiol decreased GDF-15 secretion through androgen receptor/estrogen receptor-mediated pathways. Together, these results suggest that upregulation of GDF-15 in the presence of low and imbalanced sex hormone levels may contribute to CAD. Thus, restoring the balance of testosterone and estradiol may inhibit the effects of GDF-15 and serve as a promising therapeutic strategy for the treatment of CAD.

Testosterone and All-Cause Mortality in Older Men: The Role of Metabolic Syndrome

Previous studies have shown controversial results about the role of testosterone in all-cause mortality in elderly men. We hypothesized that metabolic syndrome (MetS) could partly explain this discrepancy. We therefore examined the association of all-cause mortality with total and bioavailable testosterone, taking into account the MetS. We used data from the Three-City Cohort (3C) study with 12-year follow-up. The 3C study included 3650 men aged >65 years in three French cities. Hormone was measured in a random subsample of 444 men, and MetS was determined as stated by the International Diabetes Federation criteria. We used inverse-probability-weighted Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs). Of 444 men included in the analysis, 106 (23.9%) had MetS at baseline, and 166 died over the follow-up. There was a significant interaction between testosterone level and MetS for all-cause mortality (P = 0.002 and P = 0.008 for total and bioavailable testosterone, respectively). Among men with MetS, a decrease in one standard deviation of testosterone was associated with higher mortality risk [HR 1.78 (95% CI 1.13 to 2.78) and HR 1.83 (95% CI 1.17 to 2.86) for total and bioavailable testosterone, respectively]. By contrast, there was no association of testosterone with mortality risk among men without MetS. Our results suggest that MetS modifies the association between testosterone and mortality in older men. If confirmed, these findings could contribute to improve risk stratification and better manage the health of older men.

Androgens and cardiovascular disease in women and men

Cardiovascular disease is the leading cause of death in both women and men. Its pathogenesis is multifactorial, with sex hormones playing an important role. Androgens have both direct and indirect effects on the vasculature. This review summarizes evidence on the association of both endogenous and exogenous androgens with subclinical and overt cardiovascular disease in women and men. Concerning women, both high and low levels of endogenous androgens have been associated with cardiovascular disease, while other studies have reported no association. Adiposity, impaired glucose metabolism, dyslipidemia and estrogen levels may mediate the observed associations. Regarding testosterone therapy in women, there have been no large prospective studies on cardiovascular outcomes. Concerning men, most studies indicate that low levels of circulating testosterone are associated with increased rates of cardiovascular disease in the general population; the causality, however, of this association remains to be proven. Testosterone replacement therapy in men with symptoms of hypogonadism and low serum testosterone merits caution with regard to cardiovascular safety, as evidence is still conflicting.

Role of Testosterone in the Treatment of Cardiovascular Disease

Cardiovascular disease (CVD) is the most prevalent non-communicable cause of death worldwide. Testosterone is a sex hormone that is predominant in males but also occurs in lower concentrations in females. It has effects directly on the blood vessels of the cardiovascular system and on the heart, as well as effects on risk factors for CVD. Serum testosterone concentrations are known to decrease with age and reduced testosterone levels are linked to premature coronary artery disease, unfavourable effects on CVD risk factors and increased risk of cardiovascular mortality independent of age. A significant number of men with heart failure demonstrate reduced serum testosterone concentrations and there is early evidence suggesting that low testosterone levels affect cardiac repolarisation. Any association between endogenous testosterone concentrations and CVD in women has yet to be established. Testosterone replacement is used to treat men with hypogonadism but also has cardiovascular effects. This review will present the current evidence, expert opinion and controversies around the role of testosterone in the pathophysiology of CVD and surrounding the use of testosterone treatment and its effects on the cardiovascular system and CVD.