Epidemiology: testosterone and the metabolic syndrome

Obesity and male infertility: multifaceted reproductive disruption

Background

The global prevalence of obesity has soared to a concerning height in the past few decades. Interestingly, the global decline in semen quality is a parallel occurrence that urges researchers to evaluate if obesity is among the most essential causatives of male infertility or subfertility.

Main body

Obesity may alter the synchronized working of the reproductive-endocrine milieu, mainly the hypothalamic-pituitary-gonadal (HPG) axis along with its crosstalks with other reproductive hormones. Obesity-mediated impairment in semen parameters may include several intermediate factors, which include physical factors, essentially increased scrotal temperature due to heavy adipose tissue deposits, and systemic inflammation and oxidative stress (OS) initiated by various adipose tissue-derived pro-inflammatory mediators. Obesity, via its multifaceted mechanisms, may modulate sperm genetic and epigenetic conformation, which severely disrupt sperm functions. Paternal obesity reportedly has significant adverse effects upon the outcome of assisted reproductive techniques (ARTs) and the overall health of offspring. Given the complexity of the underlying mechanisms and rapid emergence of new evidence-based hypotheses, the concept of obesity-mediated male infertility needs timely updates and pristine understanding.

Conclusions

The present review comprehensively explains the possible obesity-mediated mechanisms, especially via physical factors, OS induction, endocrine modulation, immune alterations, and genetic and epigenetic changes, which may culminate in perturbed spermatogenesis, disrupted sperm DNA integrity, compromised sperm functions, and diminished semen quality, leading to impaired male reproductive functions.

Clinical and biochemical correlates of hypogonadism in men with type 2 diabetes mellitus

Introduction

there is an association between hypogonadism and obesity, chronic hyperglycaemia, and ageing in men with type 2 diabetes mellitus (T2DM). T2DM is known to be associated with low testosterone. There is a paucity of data on the risk factors of hypogonadism in Nigerian men with T2DM. The objective of this study was to determine the clinical and biochemical correlates of hypogonadism and clinical predictors of low total testosterone levels in men with T2DM.

Methods

this was a cross-sectional study consisting of 358 men with T2DM and 179 non-diabetic men (controls). Structured Androgen Deficiency in the Ageing Male questionnaire was administered. Clinical and biochemical parameters were measured. Free testosterone was calculated from albumin, SHBG and total testosterone using Vermeulen´s method. Hypogonadism was defined as fasting TT as < 8 nmol/L with or without symptoms or TT of 8-12 nmol/L with symptoms of androgen deficiency. Low testosterone was defined as serum total testosterone levels ≤ 12 nmol/L.

Results

the mean (±SD) total testosterone of men with T2DM and controls were 8.79±3.35 nmol/L and 15.41±3.79 nmol/L respectively (p < 0.001). The risk of hypogonadism was associated with central obesity (Odds ratio [OR] 2.24, 95% confidence interval [CI] 0.38-13.07), systolic hypertension (OR 3.93, 95% CI 0.67-23.10), hyperglycaemia (OR 2.48, 95% CI 0.37-16.46) and hypercholesterolaemia (OR 2.50, 95% CI 0.43-14.61). In a multivariable regression analysis, there was a significant negative correlation between total testosterone and triglycerides (r -1.85, 95% CI -3.58 - 0.12, P = 0.04) and HDL cholesterol (r -1.25, 95% CI -5.95-3.45, P = 0.02).

Conclusion

this study shows that in men with T2DM, triglycerides and HDL cholesterol are independent correlates of hypogonadism but not central adiposity, systolic blood pressure and glycaemia. Further large prospective studies are recommended.

Biomarkers and Noncalcified Coronary Artery Plaque Progression in Older Men Treated With Testosterone

OBJECTIVE

Recent results from the Cardiovascular Trial of the Testosterone Trials showed that testosterone treatment of older men with low testosterone was associated with greater progression of noncalcified plaque (NCP). We evaluated the effect of anthropometric measures and cardiovascular biomarkers on plaque progression in individuals in the Testosterone Trial.

METHODS

The Cardiovascular part of the trial included 170 men aged 65 years or older with low testosterone. Participants received testosterone gel or placebo gel for 12 months. The primary outcome was change in NCP volume from baseline to 12 months, as determined by coronary computed tomography angiography (CCTA). We assayed several markers of cardiovascular risk and analyzed each marker individually in a model as predictive variables and change in NCP as the dependent variable.

RESULTS

Of 170 enrollees, 138 (73 testosterone, 65 placebo) completed the study and were available for the primary analysis. Of 10 markers evaluated, none showed a significant association with the change in NCP volume, but a significant interaction between treatment assignment and waist-hip ratio (WHR) (P = 0.0014) indicated that this variable impacted the testosterone effect on NCP volume. The statistical model indicated that for every 0.1 change in the WHR, the testosterone-induced 12-month change in NCP volume increased by 26.96 mm3 (95% confidence interval, 7.72-46.20).

CONCLUSION

Among older men with low testosterone treated for 1 year, greater WHR was associated with greater NCP progression, as measured by CCTA. Other biomarkers and anthropometric measures did not show statistically significant association with plaque progression.

The potential effects of anabolic-androgenic steroids and growth hormone as commonly used sport supplements on the kidney: a systematic review

BACKGROUND

Anabolic-androgenic steroids and growth hormone are among the most commonly used supplements by sportsmen and sportswomen. The aim of this systematic review is to collect and report available data about renal safety of anabolic-androgenic steroids and growth hormone (GH).

METHODS

The search strategy was in accordance with the PRISMA guideline. Seven databases such as Scopus, Medline, Embase, and ISI Web of Knowledge were searched using keywords, such as "growth hormone", "anabolic-androgenic steroids", and "kidney injury". Articles published from 1950 to December 2017 were considered. Randomized clinical trials, prospective or retrospective human studies, case series as well as case reports, and experimental (in vivo) studies were included. Twenty one clinical and experimental articles were selected (12 for anabolic-androgenic steroids and 9 for GH).

RESULTS

Anabolic-androgenic steroids can affect the kidney in different aspects. They can induce or aggravate acute kidney injury, chronic kidney disease, and glomerular toxicity. These adverse effects are mediated through pathways such as stimulating renin-angiotensin-aldosterone system, enhancing the production of endothelin, producing reactive oxygen species, over-expression of pro-fibrotic and pro-apoptotic mediators (e.g., TGF-β1), as well as inflammatory cytokines (e.g., TNF-α, IL-1b, and IL-6). Although GH may affect the kidney in different aspects, such as size, glomerular filtration rate, and tubule functions, either directly or indirectly, there is no conclusive clinical evidence about its detrimental effects on the kidney in athletes and body builders.

CONCLUSION

Evidence regarding effects of anabolic-androgenic steroids exists; However, GH's exact effect on the kidney at doses used by athletes and body builders has not yet been clarified. Cohort clinical studies with long-term follow-up are warranted in this regard.

Obesity, Male Reproductive Function and Bariatric Surgery

Overweight and obesity are associated with several chronic complications, such as type 2 diabetes, arterial hypertension and atherosclerotic cardiovascular diseases, with relevant consequences for patients and public health systems. Reproductive function abnormalities, such as obesity-related secondary hypogonadism, erectile dysfunction and infertility, represent other abnormalities negatively affecting the quality of life of men suffering from obesity but, despite their high prevalence, these are often understated because of a general lack of awareness in clinical practice. Obesity and gonadal function are closely related, with obesity being associated with hypogonadism that is reversed by body weight reduction thus ameliorating reproductive and sexual health. Clinical studies specifically evaluating the impact of non-surgical weight loss on testosterone levels sometimes showed conflicting results, whereas extensive literature has demonstrated that weight loss after bariatric surgery is correlated with an increase in testosterone levels greater than that obtained with only lifestyle interventions, suggesting the role of surgery also for the treatment of hypogonadism in obese male. However, studies concerning the consequences of bariatric surgery on overall reproductive function in the male, including also sexual activity and fertility, are limited and data regarding long-term effects are lacking. Here we present a brief review summarizing the evidence regarding the interplay between obesity and reproductive abnormalities in the obese male, together with the role of bariatric surgery for the treatment of these complications, describing both the positive effects and the limitations of this procedure.

A case series of the safety and efficacy of testosterone replacement therapy in renal failure and kidney transplant patients

Background

Hypogonadism is common in patients with renal dysfunction and does not always correct following transplantation. Recent studies show increased mortality for dialysis and transplant patients with low testosterone (T). These patients are often not treated due to concerns over efficacy and complications (both real and imagined). There is surprisingly scant literature supporting the use of T therapy in these patients. We wished to examine the results of T therapy in our patients with renal failure or following transplant.

Methods

We identified 15 men in our Men’s Health Registry treated with T who either were on dialysis or had a functioning transplant at time of therapy. Demographic, laboratory and clinical outcome data were collected from the electronic medical record.

Results

There were 3 men on dialysis and 12 with a functioning transplant. Mean age was 53.7 years (range, 39–71 years) and mean total serum T was 207.9 ng/mL (range, 45–330 ng/mL). All had bothersome symptoms including fatigue (15/15) and erectile dysfunction (ED) (14/15). Mean hematocrit was 35.8% and 9/15 were anemic. Therapy included patches in 1, topical gels in 6 and testopel pellets in 8. With a mean follow-up of 22.7 months (range, 11–58 months), mean T post therapy was 528 (range, 226–869). Mean hematocrit improved to 42.6% and 7/9 anemic patients improved out of the anemic range. There were no cardiovascular or infectious complications.

Conclusions

Symptomatic hypogonadism is common in dialysis and transplant patients and T replacement therapy can be safely given with improvement in T values and symptoms in most patients. Anemia is usually improved. Testopel pellets can be used in immunosuppressed transplant recipients without infectious complications.

Effects of testosterone undecanoate replacement and withdrawal on cardio-metabolic, hormonal and body composition outcomes in severely obese hypogonadal men: a pilot study

PURPOSE

Modifications of cardiovascular and metabolic parameters during testosterone (T) replacement and withdrawal have never been investigated in severely obese hypogonadal men.

METHODS

Twenty-four severely obese (mean BMI 42; mean age 54.5) hypogonadal men (mean T = 245 ± 52 ng/dL) were enrolled in an observational, parallel-arm, open-label, 54-week study of hypocaloric diet plus physical activity (DPE; n = 12) or DPE plus T injections (DPE + T; n = 12), followed by 24 weeks of DPE alone. Primary endpoints were variations from baseline of cardiovascular (cardiac performance, blood pressure, endothelial function, carotid intima-media thickness, CIMT; epicardial fat thickness, EF) and body composition (fat/lean mass) parameters. Secondary endpoints were variations from baseline of hormonal (T and GH) and metabolic (oral glucose tolerance test, lipids, fibrinogen) parameters.

RESULTS

At 54 weeks, DPE + T showed improvements in EF, ejection fraction, diastolic function, CIMT and endothelial function (p < 0.01 vs. controls). Also, hormonal (T, p < 0.0001; GH, p < 0.01), metabolic (HOMA, p < 0.01; microalbuminuria, p < 0.01), lipid (total cholesterol, p < 0.05) and inflammatory (fibrinogen, p < 0.05) parameters improved. After 24 weeks from T withdrawal, all cardiac and hormonal parameters returned to baseline, while fat but not lean mass and blood pressure ameliorations were maintained. An inverse relationship either between EF vs. endothelial function and EF vs. T levels was found (r (2) = -0.46, p < 0.001 and r (2) = -0.56, p < 0.0005, respectively) while direct relationship between T vs. endothelial function occurred (r (2) = 0.43, p < 0.005) in DPE + T. A 33 % dropout rate was reported in DPE without serious adverse events.

CONCLUSIONS

In middle-aged hypogonadal obese men, 1-year T treatment was safe and improved cardio-metabolic and hormonal parameters. We firstly demonstrated that T withdrawal determines a return back to hypogonadism within 6 months, with loss of cardiovascular and some body composition improvements attained.

New therapy via targeting androgen receptor in monocytes/macrophages to battle atherosclerosis

The male sex has a higher risk to develop coronary artery diseases, including atherosclerosis. The androgen receptor (AR) is expressed in several atherosclerosis-associated cell types, including monocytes/macrophages, endothelial cells (ECs), and smooth muscle cells (SMCs), but its pathophysiological role in each cell type during the development of atherosclerotic lesions remains unclear. Using the Cre-loxP system, we selectively knocked out AR in these 3 cell types and the resultant AR knockout (ARKO) mice, monocyte/macrophage ARKO, EC-ARKO, and SMC-ARKO, were then crossed with the low-density lipoprotein receptor (LDLR) deficient (LDLR(-/-)) mice to develop monocyte/macrophage ARKO-LDLR(-/-), EC-ARKO-LDLR(-/-), and SMC-ARKO-LDLR(-/-) mice for the study of atherosclerosis. The results showed that the monocyte/macrophage ARKO-LDLR(-/-) mice had reduced atherosclerosis compared with the wild-type-LDLR(-/-) control mice. However, no significant difference was detected in EC-ARKO-LDLR(-/-) and SMC-ARKO-LDLR(-/-) mice compared with wild-type-LDLR(-/-) mice, suggesting that the AR in monocytes/macrophages, and not in ECs and SMCs, plays a major role to promote atherosclerosis. Molecular mechanism dissection suggested that AR in monocytes/macrophages upregulated the tumor necrosis factor-α, integrin β2, and lectin-type oxidized LDL receptor 1 molecules that are involved in 3 major inflammation-related processes in atherosclerosis, including monocytes/macrophages migration and adhesion to human umbilical vein ECs, and subsequent foam cell formation. Targeting AR via the AR degradation enhancer, ASC-J9, in wild-type-LDLR(-/-) mice showed similar effects as seen in monocyte/macrophage ARKO-LDLR(-/-) mice with little influence on lipid profile. In conclusion, the AR in monocytes/macrophages plays key roles in atherosclerosis and targeting AR with ASC-J9 may represent a new potential therapeutic approach to battle atherosclerosis.

Role of testosterone in the pathogenesis, progression, prognosis and comorbidity of men with chronic kidney disease

Testosterone deficiency and hypogonadism are common conditions in men with chronic kidney disease (CKD). A disturbed hypothalamic-pituitary-gonadal axis due to CKD is thought to contribute to androgen deficiency. Data from experimental studies support the hypothesis that exogenous administration of testosterone may induce the activation of the renin-angiotensin system (RAS), the production of endothelin and the regulation of anti- or/and proinflammatory cytokines involved in the pathogenesis of hypertension and kidney damage. On the other hand, low testosterone levels in male patients with CKD are paradoxically associated with a higher risk of morbidity and mortality, possibly explained by anemia, osteoporosis and cardiovascular disease. In this article, we present an overview of clinical and experimental studies of the impact of testosterone on the progression and prognosis of male patients with CKD; even today, this remains a controversial issue.

The influence of obesity-related single nucleotide polymorphisms on BMI across the life course: the PAGE study

Evidence is limited as to whether heritable risk of obesity varies throughout adulthood. Among >34,000 European Americans, aged 18-100 years, from multiple U.S. studies in the Population Architecture using Genomics and Epidemiology (PAGE) Consortium, we examined evidence for heterogeneity in the associations of five established obesity risk variants (near FTO, GNPDA2, MTCH2, TMEM18, and NEGR1) with BMI across four distinct epochs of adulthood: 1) young adulthood (ages 18-25 years), adulthood (ages 26-49 years), middle-age adulthood (ages 50-69 years), and older adulthood (ages ≥70 years); or 2) by menopausal status in women and stratification by age 50 years in men. Summary-effect estimates from each meta-analysis were compared for heterogeneity across the life epochs. We found heterogeneity in the association of the FTO (rs8050136) variant with BMI across the four adulthood epochs (P = 0.0006), with larger effects in young adults relative to older adults (β [SE] = 1.17 [0.45] vs. 0.09 [0.09] kg/m², respectively, per A allele) and smaller intermediate effects. We found no evidence for heterogeneity in the association of GNPDA2, MTCH2, TMEM18, and NEGR1 with BMI across adulthood. Genetic predisposition to obesity may have greater effects on body weight in young compared with older adulthood for FTO, suggesting changes by age, generation, or secular trends. Future research should compare and contrast our findings with results using longitudinal data.

A randomized, double-blind, placebo-controlled trial of testosterone gel on body composition and health-related quality-of-life in men with hypogonadal to low-normal levels of serum testosterone and symptoms of androgen deficiency over 6 months with 12 months open-label follow-up

INTRODUCTION

The clinical significance of low to low-normal testosterone (T) levels in men remains debated.

AIM

To analyze the effects of raising serum T on lean body mass (LBM), fat mass (FM), total body mass, and health-related quality-of-life (HRQoL).

METHODS

Randomized, double-blind, placebo-controlled study. Men, aged 50-80 years, with serum total T<15 nmol/L and bioavailable T < 6.68 nmol/L, and a Aging Males' Symptoms (AMS) total score >36, received 6 months treatment with transdermal 1% T gel (5-7.5 mg/day; n =183) or placebo gel (n =179), followed by 12 months open-label with T in all.

RESULTS

After 6 months, LBM increased in T- treated patients by 1.28 ± 0.15 kg (mean ± SE) and FM decreased by 1.16 ± 0.16 kg, with minor changes with placebo (LBM +0.02 ± 0.10 kg and FM -0.14 ± 0.12 kg; all p < 0.001, T group vs. placebo). Changes were largely similar across subgroups of age, baseline total testosterone, and baseline BMI. Total HRQoL improved compared with placebo (p < 0.05, T group vs. placebo).

CONCLUSIONS

Six months 1% T gel improved body composition and HRQoL in symptomatic men with low to low-normal T, with further improvements over the following 12 months.

Waist-to-height ratio as a predictor of serum testosterone in ageing men with symptoms of androgen deficiency

The decline in serum testosterone in ageing men may be mediated in part by obesity; however, it is uncertain which measure of adiposity is most closely associated with testosterone levels. We have examined the relationships of age, adiposity and testosterone levels in ageing men with symptoms consistent with hypoandrogenism but who were otherwise in good health. We conducted a cross-sectional study of non-smoking men aged ≥ 54 years recruited from the community and who were free of cancer or serious medical illness. Height (Ht), weight and waist circumference (WC) were measured, and body mass index (BMI) and waist-to-height (WHt) ratio were calculated. Two morning blood samples were collected for measurement of total testosterone (TT), sex hormone binding globulin (SHBG) and luteinizing hormone (LH). Free testosterone (cFT) was calculated. Multivariate linear regression analysis was performed to assess their relationship with measures of adiposity. Two hundred and seven men aged 54-86 years were studied. On univariate analysis WHt ratio was more strongly correlated with TT and cFT than either WC or BMI. Furthermore, in models of TT and cFT, the addition of Ht to WC resulted in an increase in the magnitude of the regression coefficients for both WC (inverse correlate) and Ht (positive correlate), with the contributions of both WC and Ht both being significant (P<0.05 for all). In conclusion, WHt ratio is the best anthropometric predictor of both TT and cFT in this group of healthy but symptomatic ageing men.

Hypogonadism risk in men treated for childhood cancer

CONTEXT

Pediatric cancer treatment may imply an increased risk of hypogonadism, leading to metabolic disorders and osteoporosis. Such complications are potentially preventable.

OBJECTIVE

The aim of this study was to assess diagnosis- and treatment-dependent risk of hypogonadism in male childhood cancer survivors (CCS).

DESIGN

Male CCS who were treated during the period 1970-2002 and who in 2004 were 18-45 yr of age were eligible.

SETTING

The study was conducted in a university hospital clinic.

PATIENTS

A consecutive group of CCS treated at Lund University Hospital was selected for the study, of whom 151 (38%) agreed to participate. Furthermore, 141 healthy fertile men served as controls.

INTERVENTIONS

We measured serum levels of free and total testosterone, SHBG, and LH.

MAIN OUTCOME MEASURES

Odds ratios (OR) for biochemical hypogonadism, defined as total testosterone less than 10 nmol/liter and/or LH above 10 IU/liter, were calculated and related to type of cancer, treatment received, as well as testicular volume.

RESULTS

Hypogonadism was more commonly detected in CCS than in controls (OR, 6.7; 95% CI, 2.7, 17). The increased presence of hypogonadism was noted in the following treatment groups: brain surgery, chemotherapy (with and without radiotherapy), and testicular irradiation. Low total testicular volume (<or=24 ml) was associated with a high risk of hypogonadism (OR, 31; 95% CI, 11, 92).

CONCLUSION

Adult male survivors of childhood cancer are at risk of hypogonadism, which should be acknowledged in the long-term follow-up of these men.

Metabolic syndrome and erectile dysfunction among obese non-diabetic subjects

OBJECTIVE

To investigate whether MS is associated with erectile dysfunction (ED) among obese non diabetic individuals.

METHODS

A cross-sectional study was carried out to examine the association between the cluster of abnormalities related to the MS and ED as evaluated by the International Index of Erectile Function (IIEF). Fifty consecutive obese [i.e. body mass index (BMI) > or =30 kg/m2], nondiabetic whites (age 42.1+/-11.3 yr, BMI 43.3+/-8.7 kg/m2) were recruited.

RESULTS

The prevalence of MS as well as that of any MS component were not different between subjects with or without ED. Neither the prevalence of ED (34.3% vs 33.4%, p=0.6), nor IIEF score (21.5+/-3.9 vs 21.7+/-3.7, p=0.8), were different between patients with or without MS. IIEF was similar across subgroups of individuals stratified according to the number of MS components and was not related to HOMAIR index. Hypogonadism was observed in 30.8% and 28.1% individuals with and without MS (p=0.58). Testosterone and BMI levels were inversely related (r=-0.3, p=0.04).

CONCLUSION

Among obese non-diabetic individuals the risk of developing ED is independent of the presence of MS factors. Testosterone levels progressively decrease with increasing body weight.

Prevalence of low male testosterone levels in primary care in Germany: cross-sectional results from the DETECT study

OBJECTIVE

Low testosterone levels in men occur with increasing age and are associated with increased morbidity, particularly metabolic syndrome, and mortality. As the prevalence of hypogonadal testosterone levels has not been assessed in the primary care setting in Europe, we aimed to investigate the prevalence of low testosterone levels in this setting, and the patient characteristics and comorbidities associated with this finding.

DESIGN

A cross-sectional, epidemiological study (the Diabetes Cardiovascular Risk-Evaluation: Targets and Essential Data for Commitment of Treatment (DETECT) study).

PATIENTS

A total of 2719 male primary care patients (age 58.7 +/- 13.4 years) were included.

MEASUREMENTS

Testosterone was measured in all patients. Information on diseases, risk conditions and treatments was documented by the primary care physicians. A large set of laboratory parameters was measured in a central laboratory. We calculated univariate and multivariate logistic regression models to assess the associations of low testosterone levels with different health and life style factors.

RESULTS

A total of 19.3% of all men had hypogonadism as defined by testosterone levels < 3.0 ng/ml. Stepwise logistic regression analysis revealed that obesity, metabolic syndrome, cancer, intake of six or more drugs, acute inflammation and nonsmoking were associated with hypogonadal testosterone levels. Higher age, liver diseases, and cancer were associated with very low testosterone levels (< 1.0 ng/ml).

CONCLUSIONS

Hypogonadal testosterone levels are common in primary care, particularly in patients with the above conditions.

Androgen receptor gene polymorphism and the metabolic syndrome in 60-80 years old Norwegian men

The metabolic syndrome (MS) includes a clustering of metabolic derangements. Low testosterone levels have been shown to be associated with both components of MS and MS per se. As most androgen-related effects are mediated thorough the androgen receptor (AR), we wanted to investigate to which degree the AR CAG and GGN repeat polymorphisms might be related to MS. Sixty-eight men, 60-80 years old, with subnormal total testosterone levels (<or=11.0 nmol/L) and 104 men with normal levels (>11.0 nmol/L), participating in a nested case-control study were investigated in this study. Body weight, height, waist circumferences and blood pressure were measured. Fasting blood samples were drawn and an oral glucose tolerance test (OGTT) was performed. The CAG and GGN polymorphisms in the AR gene were determined by direct sequencing of leucocyte DNA. Men with MS had lower CAG repeat number than healthy men (p = 0.007). There were, however, no difference in CAG or GGN repeats length between the groups with subnormal or normal testosterone concentrations. In cross-sectional analyses, men with CAG repeat lengths <or= 21 had significantly higher fasting glucose, C-peptide and glycosylated haemoglobin (HbA1c) levels (all p < 0.05). In multiple regression analyses, CAG repeat length was an inverse and independent predictor of glucose after an OGTT and of HbA1c levels. We also found that men with more than one component of MS had shorter CAG repeat number (p for trend 0.013) than those with only one component. In conclusion, there were no associations with GGN repeat length, while short CAG repeat length seems to be associated with increased risk of MS.

Hypogonadotrophic hypogonadism in type 2 diabetes

Recent work shows a high prevalence of low testosterone and inappropriately low luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations in type 2 diabetes. This syndrome of hypogonadotrophic hypogonadism (HH) is associated with obesity in patients with type 2 diabetes. However, the duration of diabetes or HbA1c are not related to HH. Furthermore, recent data show that HH is not associated with type 1 diabetes. C-reactive protein concentrations have been shown to be elevated in patients with HH and are inversely related to plasma testosterone concentrations. This inverse relationship between plasma free testosterone and C- reactive protein concentrations in patients with type 2 diabetes suggests that inflammation may play an important role in the pathogenesis of this syndrome. This is of interest since inflammatory mechanisms may have a cardinal role in the pathogenesis of insulin resistance. It is also relevant that in the mouse, deletion of the insulin receptor in neurons leads to HH in addition to a state of systemic insulin resistance. It has also been shown that insulin facilitates the secretion of gonadotrophin releasing hormone (GnRH) from neuronal cell cultures. Thus, HH may be the result of insulin resistance at the level of the GnRH secreting neuron. Low testosterone concentrations are also related to an increase in total and regional adiposity. This review discusses these issues and attempts to make the syndrome relevant as a clinical entity. Clinical trials are required to determine whether testosterone replacement alleviates insulin resistance and inflammation. In addition, low testosterone levels are associated with an increase in cardiovascular events. Testosterone therapy may therefore, reduce cardiovascular risk. This important aspect requires further investigation.

The triad of erectile dysfunction, hypogonadism and the metabolic syndrome

AIM

To identify the relationship of erectile dysfunction, hypogonadism and the metabolic syndrome in the context of men's health.

METHODS

An Expert Panel Meeting was held in December 2006 in Vienna, Austria. In addition a comprehensive literature search was conducted.

RESULTS

Men have a higher incidence of cardiovascular events than women of similar ages which has led to the belief that testosterone is a risk factor for cardiovascular disease in men. The latter hypothesis is no longer tenable. On the contrary, low testosterone levels are associated with (visceral) obesity, the metabolic syndrome, diabetes mellitus, cardiovascular disease and erectile dysfunction (ED). Testosterone therapy does not lead to an increased incidence of cardiovascular disease or events such as myocardial infarction, stroke or angina. Until recently (visceral) obesity, the metabolic syndrome, diabetes mellitus, cardiovascular disease and ED were viewed as more or less independent entities affecting the ageing male. It was not recognised that hypogonadism is a common denominator. With a more integrative approach to the health situation of middle-aged and elderly men, these conditions appear closely interrelated in their manifestations, hypothetically in their aetiology, diagnostic strategy and also their treatment.

CONCLUSION

Improving sexual health is a portal to identify health hazards and improving men's health. Appropriate diagnosis and medical work up of men presenting with sexual symptoms may have the benefit of the diagnosing and treating other important conditions, such as obesity, diabetes, hypertension and hyperlipidaemia.

The prevalence of and risk factors for androgen deficiency in aging Taiwanese men

INTRODUCTION

Androgen deficiency in aging men has attracted much medical interest. Most studies on androgen deficiency have been conducted in Caucasian populations, and data from other ethnicities are lacking.

AIM

To evaluate the prevalence of and risk factors for androgen deficiency and symptomatic androgen deficiency in Taiwanese men over 40 years old.

METHODS

From August 2007 to April 2008, a free health screening was conducted by a medical center in Kaohsiung, Taiwan, and 819 men participated in this health screening. All participants completed a health questionnaire, received a detailed physical examination, and blood samples were drawn between 8:00 and 12:00 am.

MAIN OUTCOME MEASURES

Serum total testosterone (TT), albumin, and sex hormone-binding globulin levels were measured. The level of free testosterone (FT) was calculated. Clinical symptoms of androgen deficiency were assessed using the Androgen Deficiency in the Aging Male (ADAM) questionnaire.

RESULTS

Seven hundred thirty-four men who met the inclusion criteria (mean age 57.4 +/- 6.7 years; range: 43-87 years) were included in this study. The prevalence of androgen deficiency was 24.1% based on the criterion of TT level < 300 ng/dL, and 16.6% based on the criterion of both TT < 300 ng/dL and FT < 5 ng/dL. The prevalence of symptomatic androgen deficiency was 12.0%. Both prevalence of androgen deficiency and symptomatic androgen deficiency increased with age. Older age, obesity, and diabetes mellitus were independent risk factors for androgen deficiency and symptomatic androgen deficiency.

CONCLUSIONS

In a sample of aging Taiwanese men, a substantial proportion had androgen deficiency and symptomatic androgen deficiency, and the prevalence increased with age. Older age, obesity, and diabetes mellitus were independent risk factors for androgen deficiency and symptomatic androgen deficiency. Those potentially modifiable risk factors like obesity and diabetes mellitus should be prevented to maintain normal testosterone levels during aging in men.

Adrenocortical dysregulation as a major player in insulin resistance and onset of obesity

The aim of this review is to explore the dysregulation of adrenocortical secretions as a major contributor in the development of obesity and insulin resistance. Disturbance of adipose tissue physiology is one of the primary events in the development of pathologies associated with the metabolic syndrome, such as obesity and type 2 diabetes. Several studies indicate that alterations in metabolism of glucocorticoids (GC) and androgens, as well as aldosterone in excess, are involved in the emergence of metabolic syndrome. Cross talk among adipose tissue, the hypothalamo-pituitary complex, and adrenal gland activity plays a major role in the control of food intake, glucose metabolism, lipid storage, and energy balance. Perturbation of this cross talk induces alterations in the regulatory mechanisms of adrenocortical steroid synthesis, secretion, degradation, and/or recycling, at the level of the zonae glomerulosa (aldosterone), fasciculata (GC and GC metabolites), and reticularis (androgens and androgen precursors DHEA and DHEAS). As a whole, these adrenocortical perturbations contribute to the development of metabolic syndrome at both the paracrine and systemic level by favoring the physiological dysregulation of organs responsive to aldosterone, GC, and/or androgens, including adipose tissue.

ORIGINAL RESEARCH—ENDOCRINOLOGY: NCEP-ATPIII-Defined Metabolic Syndrome, Type 2 Diabetes Mellitus, and Prevalence of Hypogonadism in Male Patients with Sexual Dysfunction

INTRODUCTION

Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) are characterized by insulin resistance and often associated with male hypogonadism.

AIM

To discriminate the specific contribution of T2DM and MetS to male hypogonadism.

METHODS

A consecutive series of 1,134 (mean age 52.1 +/- 13 years) male patients with sexual dysfunction was studied.

MAIN OUTCOME MEASURES

Several hormonal and biochemical parameters were studied along with ANDROTEST, a 12-item validated structured interview, specifically designed for the screening of hypogonadism (total testosterone [TT] <10.4 nmol/L or free testosterone [FT] <37 pmol/L) in a male population with sexual dysfunction.

RESULTS

Irrespective of the criteria used to define hypogonadism, MetS was associated with a significantly higher prevalence of the condition, both in subjects with and without T2DM (41% and 29% vs. 13.2% and 77.1% and 58% vs. 40.6%, respectively, for TT and FT in patients with MetS and with or without T2DM, when compared with subjects without MetS and T2DM; both P < 0.0001). Conversely, T2DM was associated with a higher prevalence of hypogonadism in subjects with MetS but not in those without MetS. Patients with MetS, with or without T2DM, also showed a higher ANDROTEST score when compared with patients without MetS. Logistic multivariate regression analysis, incorporating the five components of MetS, identified a significant association of elevated waist circumference and hypertriglyceridemia with hypogonadism both in patients, with or without T2DM.

CONCLUSIONS

Our study demonstrated that MetS, and in particular visceral adiposity (as assessed by increased waistline and hypertriglyceridemia), is specifically associated with hypogonadism in subjects consulting for sexual dysfunction.

Androgen deficiency, diabetes, and the metabolic syndrome in men

PURPOSE OF REVIEW

The burden of androgen deficiency in men with diabetes and the metabolic syndrome has become increasingly apparent in population-based studies. This article focuses on the mechanisms underlying the interdependent relationship between these conditions.

RECENT FINDINGS

Various definitions of hypogonadism, the metabolic syndrome and diabetes have been proposed and are used in the literature. Cross-sectional studies have found that between 20 and 64% of men with diabetes have hypogonadism, with higher prevalence rates found in the elderly. Hypogonadism can be a risk factor for the development of diabetes and the metabolic syndrome through various mechanisms including changes in body composition; androgen receptor polymorphisms; glucose transport; and reduced antioxidant effect. Conversely, diabetes and the metabolic syndrome can be risk factors for hypogonadism through some similar but mostly distinct mechanisms, such as increased body weight; decreased sex hormone binding globulin levels; suppression of gonadotrophin release or Leydig cell testosterone production; cytokine-mediated inhibition of testicular steroid production; and increased aromatase activity contributing to relative estrogen excess.

SUMMARY

The relationship between diabetes, the metabolic syndrome and androgen deficiency is complex. Testosterone supplementation, by either oral or intramuscular routes and through exogenous or endogenous delivery, has a promising role in this population although further clinical trials are needed.