Testosterone and glucose metabolism in men: current concepts and controversies

Associations between social network addiction, anxiety symptoms, and risk of metabolic syndrome in Peruvian adolescents-a cross-sectional study

Background

The link between physical and mental health and screen time in adolescents has been the subject of scientific scrutiny in recent years. However, there are few studies that have evaluated the association between social network addiction (SNA) and metabolic risk in this population.

Objective

This study determined the association between SNA and anxiety symptoms with the risk of metabolic syndrome (MetS) in adolescents.

Methods

A cross-sectional study was conducted in Peruvian adolescents aged 12 to 18 years, who completed a Social Network Addiction Questionnaire and the Generalized Anxiety Disorder 2-item scale (GAD-2), between September and November 2022. A total of 903 participants were included in the study using a non-probability convenience sample. Sociodemographic and anthropometric data were also collected. Binary logistic regression was used to explore the association between SNA and anxiety symptoms with MetS in a cross-sectional analysis.

Results

Males were more likely to have MetS than females (OR = 1.133, p = 0.028). Participants who were 16 years of age or older and those with excess body weight were 2.166, p = 0.013 and 19.414, p < 0.001 times more likely to have MetS, respectively. Additionally, SNA (OR = 1.517, p = 0.016) and the presence of anxiety symptoms (OR = 2.596, p < 0.001) were associated with MetS.

Conclusion

Our findings suggest associations between SNA, anxiety symptoms, and MetS among youth. However, more studies are needed to better understand this association and to deepen the possible clinical and public health implications.

The association of testosterone with sarcopenia and frailty in chronic liver disease

BACKGROUND

Testosterone is an important anabolic hormone responsible for maintaining body composition and muscle mass and circulates mostly albumin-bound, or sex hormone binding globulin (SHBG)-bound or free in the plasma. Of these fractions, the latter is bioactive and exerts the androgenic effects on male population. Liver cirrhosis, the advanced stage of any chronic liver disease characterized by permanent distortions to the hepatic architecture, disrupts the hypothalamic-pituitary-gonadal axis, leading to diminished levels of free testosterone and hypogonadism.

METHODS

We retrieved the PubMed database to provide a synopsis of testosterone's physiology and action and summarize the effect of sarcopenia in pre-cirrhotic and cirrhotic patients. Moreover, we scoped to provide insight into the relationship of testosterone levels with sarcopenia, frailty and survival in cirrhotic and non-cirrhotic population as well as to discuss the efficacy of exogenous testosterone supplementation on the anthropometric parameters and survival of those patients.

RESULTS

Low testosterone levels have been associated with sarcopenia, reduced body lean mass, decreased bone mineral density and frailty, thus leading to increased morbidity and mortality especially among cirrhotic patients. Furthermore, exogenous testosterone administration significantly ameliorated body composition on patients with chronic hepatic disease, without significant adverse effects. However, the current literature does not suggest any significant effect on survival of those patients. Moreover, the long-term safety of testosterone use remains an open question.

CONCLUSION

Low serum testosterone is strongly correlated with sarcopenia, frailty, higher rate of hepatic decompensation and mortality. Nonetheless, exogenous supplementation of testosterone did not ameliorate the liver-related outcomes and complications.

Evaluation of Tibial Hemodynamic Response to Glucose Tolerance Test in Young Healthy Males and Females

The relationship between glucose metabolism and bone health remains underexplored despite its clinical relevance. This study utilized the oral glucose tolerance test (OGTT) and near-infrared spectroscopy (NIRS) to probe gender-specific disparities in tibial hemodynamic responses among young healthy adults. Twenty-eight healthy participants (14 males) aged 18-28 years old were recruited for this study. After ingesting a 75 g glucose solution, tibial hemodynamic responses were captured using NIRS in combination with a 5 min ischemic reperfusion technique, both before and at 30 min intervals for two hours post-glucose ingestion. Parameters measured included oxidative metabolic rate (via tissue saturation index [TSI]), immediate recovery slope after occlusion release (TSI10), and total recovery magnitude (ΔTSI). Post-glucose ingestion, both genders demonstrated a surge in blood glucose concentrations at every time point compared to baseline (p < 0.001, 0.002, 0.009, and 0.039 for males; p < 0.001, < 0.001, = 0.002, and 0.017 for females). Baseline tibial metabolic rate, TSI10, and ΔTSI did not significantly differ between males and females (p = 0.734, 0.839, and 0.164, respectively), with no discernible temporal effects in any hemodynamic parameters within each gender (p = 0.864, 0.308, and 0.399, respectively, for males; p = 0.973, 0.453, and 0.137, respectively, for females). We found comparable tibial hemodynamic responses to OGTT between genders. This study demonstrated the utility of NIRS in evaluating tibial hemodynamic responses to glucose ingestion through OGTT, enriching our understanding of the body's metabolic responses to glucose intake.

The complications of male hypogonadism: is it just a matter of low testosterone?

The history of diagnosing hypogonadism and hypotestosteronemia shows us the many steps that were necessary to achieve our current knowledge and the ability to improve these patients' well-being. Moreover, so far, criteria for diagnosing hypotestosteronemia varies according to the underlying condition, and according to the consensus or guideline adopted. Furthermore, besides the many signs and symptoms, there are several complications associated with low testosterone levels such as osteoporosis, metabolic alterations, as well as cardiovascular disorders. However, data are often conflicting regarding the severity, timing or even the real clinical relevance of these complications, although these studies often lack essential information such as gonadotropin levels or the underlying cause of hypogonadism. The present review focus on the complications of male hypogonadism according to the cause of testosterone deficiency, highlighting the lack of information found in many studies investigating its effects. We thereby stress the necessity to always perform a complete evaluation of the type of hypogonadism (including at least gonadotropins and secondary causes) when investigating the effects of low testosterone levels.

Immunomodulatory effects of testosterone and letrozole during Plasmodium berghei ANKA infection

Introduction

Malaria is one of the leading health problems globally. Plasmodium infection causes pronounced sexual dimorphism, and the lethality and severity are more remarkable in males than in females. To study the role of testosterone in the susceptibility and mortality of males in malaria, it is common to increase its concentration. However, this strategy does not consider the enzyme CYP19A1 aromatase, which can transform it into oestrogens.

Methods

To avoid the interference of oestrogens, we inhibited in vivo CYP19A1 aromatase with letrozole and increased the testosterone level by exogen administration before infection with Plasmodium berghei ANKA. We measured the impact on free testosterone, 17β-oestradiol and dehydroepiandrosterone levels in plasma; additionally, we evaluated parasitaemia, body temperature, body mass, glucose levels and haemoglobin concentration. Furthermore, we evaluated the effects of testosterone on the immune response; we quantified the CD3+/CD4+, CD3+/CD8+, CD19+, Mac-3+ and NK cells in the spleen and the plasma concentrations of the cytokines IL-2, IL-4, IL-6, IFN-, IL-10, TNF-α and IL-17A. Finally, we quantified the levels of antibodies.

Results

We found that mice treated with the combination of letrozole and testosterone and infected with Plasmodium berghei ANKA had increased concentrations of free testosterone and DHEA but decreased levels of 17β-oestradiol. As a result, parasitaemia increased, leading to severe anaemia. Interestingly, testosterone increased temperature and decreased glucose concentration as a possible testosterone-mediated regulatory mechanism. The severity of symptomatology was related to critical immunomodulatory effects generated by free testosterone; it selectively increased CD3+CD8+ T and CD19+ cells but decreased Mac-3+. Remarkably, it reduced IL-17A concentration and increased IL-4 and TNF-α. Finally, it increased IgG1 levels and the IgG1/IgG2a ratio. In conclusion, free testosterone plays an essential role in pathogenesis in male mice by increasing CD8+ and decreasing Mac3+ cells and mainly reducing IL-17A levels, which is critical in the development of anaemia. Our results are important for understanding the mechanisms that regulate the exacerbated inflammatory response in infectious diseases and would be useful for the future development of alternative therapies to reduce the mortality generated by inflammatory processes.

Biomarkers to Be Used for Decision of Treatment of Hypogonadal Men with or without Insulin Resistance

Male hypogonadism is a result of low testosterone levels, but patients could be insulin-sensitive (IS) or insulin-resistant (IR), showing different impaired metabolic pathways. Thus, testosterone coadministration, which is commonly used to reestablish testosterone levels in hypogonadism, must take into account whether or not insulin is still active. By comparing metabolic cycles recorded in IS and IR plasma before and after testosterone therapy (TRT), it is possible to know what metabolic pathways can be reactivated in the two different groups upon testosterone recovery, and it is possible to understand if antagonism or synergy exists between these two hormones. IS hypogonadism uses glycolysis, while IR hypogonadism activates gluconeogenesis through the degradation of branched-chain amino acids (BCAAs). Upon administration of testosterone, acceptable improvements are observed in IS patients, wherein many metabolic pathways are restored, while in IR patients, a reprogramming of metabolic cycles is observed. However, in both subgroups, lactate and acetyl-CoA increases significantly. In IS patients, lactate is used through the glucose-lactate cycle to produce energy, while in IR patients, both lactate and acetyl-CoA are metabolized into ketone bodies, which are used to produce energy. Thus, in IR patients, an ancestral molecular mechanism is activated to produce energy, mimicking insulin effects. Regarding lipids, in both groups, the utilization of fatty acids for energy (β-oxidation) is blocked, even after TRT; free fatty acids (FFAs) increase in the blood in IS patients, while they are incorporated into triglycerides in those with IR. In both subgroups of hypogonadism, supplementation of useful chemicals is recommended during and after TRT when metabolites are not restored; they are listed in this review.

Male Sex Hormones, Metabolic Syndrome, and Aquaporins: A Triad of Players in Male (in)Fertility

Infertility is becoming a chronic and emerging problem in the world. There is a resistant stigma that this health condition is mostly due to the female, although the literature supports that the responsibility for the onset of infertility is equally shared between both sexes in more or less equal proportions. Nevertheless, male sex hormones, particularly testosterone (T), are key players in male-related infertility. Indeed, hypogonadism, which is also characterized by changes in T levels, is one of the most common causes of male infertility and its incidence has been interconnected to the increased prevalence of metabolic diseases. Recent data also highlight the role of aquaporin (AQP)-mediated water and solute diffusion and the metabolic homeostasis in testicular cells suggesting a strong correlation between AQPs function, metabolism of testicular cells, and infertility. Indeed, recent studies showed that both metabolic and sexual hormone concentrations can change the expression pattern and function of AQPs. Herein, we review up-to-date information on the involvement of AQP-mediated function and permeability in men with metabolic syndrome and testosterone deficit, highlighting the putative mechanisms that show an interaction between sex hormones, AQPs, and metabolic syndrome that may contribute to male infertility.

Amylin regulates testosterone levels via steroidogenesis-related enzymes in the central nervous system of male mice

Amylin is a peripheral satiation signal polypeptide co-secreted with insulin by pancreatic β-cells in response to nutrient ingestion. Amylin participates in the eating-inhibitory effect and regulates energy metabolism by acting on the central nervous system (CNS). However, the role of amylin in regulating the biosynthesis of steroid hormones, such as testosterone, through the hypothalamic-pituitary-gonadal axis (HPG) remains unexplored. However, only limited evidence is available on the involvement of amylin in steroid synthesis, we hypothesize that amylin regulates testosterone levels via steroidogenesis-related enzymes in the CNS. In this study, we elucidated the effect of intraperitoneal injection of amylin on the protein expression of steroidogenesis-related enzymes, including 3β-hydroxysteroid dehydrogenase (3β-HSD), cytochrome P450 17A1 (CYP17A1), and steroidogenic acute regulatory protein (StAR), and phospho-extracellular signal-regulated kinase (pERK). Additionally, the effect of amylin on testosterone levels in male mice was examined. Our results suggested that 3β-HSD and CYP17A1 neurons were widely expressed in the CNS of male mice, whereas StAR neurons were mainly expressed in the zona incerta (ZI) and locus coeruleus (LC) regions. Intraperitoneal injection of amylin significantly reduced (p < 0.01) the expression of 3β-HSD, CYP17A1, and StAR in ZI and other areas near the third ventricle (3 V) but increased (p < 0.01) pERK expression, brain testosterone levels, serum FSH, serum LH, and decreased (p < 0.01) serum testosterone levels in mice. In conclusion, amylin regulates testosterone levels via steroidogenesis-related enzymes in the central nervous system of male mice.

On the Need to Distinguish between Insulin-Normal and Insulin-Resistant Patients in Testosterone Therapy

Male hypogonadism is a disorder characterized by low levels of the hormone testosterone and patients may also have insulin sensitivity (IS) or insulin resistance (IR), such that they show different clinical complications and different metabolic pathways. In this review, we compare metabonomic differences observed between these two groups before and after testosterone therapy (TRT) in order to obtain information on whether the two hormones testosterone and insulin are synergistic or antagonistic. IS hypogonadism uses glucose as the main biofuel, while IR activates gluconeogenesis by the degradation of branched-chain amino acids. The Krebs (TCA) cycle is active in IS but connected with glutaminolysis, while in IR the TCA cycle stops at citrate, which is used for lipogenesis. In both cases, the utilization of fatty acids for energy (β-oxidation) is hampered by lower amounts of acetylcarnitine, although it is favored by the absence of insulin in IR. Increased free fatty acids (FFAs) are free in the blood in IS, while they are partially incorporated in triglycerides in IR. Thus, upon TRT, the utilization of glucose is increased more in IS than in IR, revealing that in IR there is a switch from preferential glucose oxidation to lipid oxidation. However, in both cases, a high production of lactate and acetyl-CoA is the final result, with these levels being much higher in IR. Lactate is used in IS in the glucose–lactate cycle between the liver and muscle to produce energy, while in IR lactate and acetyl-CoA are biotransformed into ketone bodies, resulting in ketonuria. In conclusion, the restoration of testosterone values in hypogonadism gives better results in IS than in IR patients: in IS, TRT restores most of the metabolic pathways, while in IR TRT impairs insulin, and when insulin is inactive TRT activates an ancestral molecular mechanism to produce energy. This evidence supports the hypothesis that, over time, hypogonadism switches from IS to IR, and in the latter case most of the insulin-related metabolisms are not reactivated, at least within 60 days of TRT. However, testosterone therapy in both IS and IR might be of benefit given supplementation with metabolites that are not completely restored upon TRT, in order to help restore physiological metabolisms. This review underlines the importance of using a systems biology approach to shed light on the molecular mechanisms of related biochemical pathways involving insulin and testosterone.

Plasma Metabonomics in Insulin-Resistant Hypogonadic Patients Induced by Testosterone Treatment

Hypogonadic subjects with insulin resistance (IR) showed different metabonomic profiles compared to normo-insulinemic subjects (IS). Testosterone replacement therapy (TRT) may have a different impact on the metabolisms of those with the presence or absence of insulin resistance. We evaluated the changes in the metabolism of IR hypogonadic patients before and after 60 days of TRT. The metabonomic plasma profiles from 20 IR hypogonadal patients were recorded using ultra-high-performance liquid chromatography (UHPLC) and high-resolution mass spectrometry (HRMS). Plasma metabolites, before and after 60 days of TRT, were compared. In hypogonadic patients, carnosine, which is important for improving performance during exercise, increased. Conversely, proline and lysine—amino acids involved in the synthesis of collagen—reduced. Triglycerides decreased and fatty acids (FFAs) increased in the blood as a consequence of reduced FFA β-oxidation. Glycolysis slightly improved, while the Krebs cycle was not activated. Gluconeogenesis (which is the main energy source for hypogonadal IR before TRT) stopped after treatment. As a consequence, lactate and acetyl CoA increased significantly. Both lactate and acetyl CoA were metabolized into ketone bodies which increased greatly, also due to leucine/isoleucine degradation. Ketone bodies were derived predominantly from acetyl CoA because the reaction of acetyl CoA into ketone bodies is catalyzed by mtHMGCoA synthase. This enzyme is inhibited by insulin, which is absent in IR patients but overexpressed following testosterone administration. Ketosis is an alternative route for energy supply and provides the same metabolic effects as insulin but at the metabolic or primitive control level, which bypasses the complex signaling pathway of insulin. After treatment, the hypogonadic patients showed clinical symptoms related to ketonuria. They presented similarly to those following a ketogenic diet, the so-called ‘keto flu’. This must be taken into account before the administration of TRT to hypogonadic patients.

Plasma Metabolomics Profile of "Insulin Sensitive" Male Hypogonadism after Testosterone Replacement Therapy

Male hypogonadism is a disorder characterized by low levels of testosterone, but patients can either show normal insulin (insulin-sensitive (IS)) or over time they can become insulin-resistant (IR). Since the two groups showed different altered metabolisms, testosterone replacement therapy (TRT) could achieve different results. In this paper, we analyzed plasma from 20 IS patients with low testosterone (<8 nmol/L) and HOMAi < 2.5. The samples, pre- and post-treatment with testosterone for 60 days, were analyzed by UHPLC and mass spectrometry. Glycolysis was significantly upregulated, suggesting an improved glucose utilization. Conversely, the pentose phosphate pathway was reduced, while the Krebs cycle was not used. Branched amino acids and carnosine metabolism were positively influenced, while β-oxidation of fatty acids (FFA) was not activated. Cholesterol, HDL, and lipid metabolism did not show any improvements at 60 days but did so later in the experimental period. Finally, both malate and glycerol shuttle were reduced. As a result, both NADH and ATP were significantly lower. Interestingly, a significant production of lactate was observed, which induced the activation of the Cori cycle between the liver and muscles, which became the main source of energy for these patients without involving alanine. Thus, the treatment must be integrated with chemicals which are not restored in order to reactivate energy production.

U-shaped association between prevalence of secondary hypogonadism and body mass index: a retrospective analysis of men with testosterone deficiency

The prevalence of both obesity and hypogonadism in the United States has increased over the past two decades. While prior studies have shown an association between obesity and secondary hypogonadism-low testosterone and luteinizing hormone-few have used a large enough sample size to determine prevalence at each body mass index class. We aimed to compare rates of secondary hypogonadism among body mass index classes by constructing a retrospective database with men who had their body mass index, morning testosterone and luteinizing hormone levels measured during a visit to a urology clinic at a tertiary academic medical center between 2011-2020. Men previously on testosterone replacement therapy, Clomiphene, or Anastrozole were excluded. Chi-squared analysis was conducted in "R". We found that among the 7211 men studied, 45.7%, 22.6%, and 4.4% were classified as having diagnosis of secondary, primary, and compensated hypogonadism, respectively. We found that obese men and underweight men had increased prevalence of secondary hypogonadism as compared to men with normal body mass index. These findings support the need for routine screening criteria and personalized advice to patients dealing with secondary hypogonadism.

Melatonin ameliorates endocrine dysfunction and defective sperm integrity associated with high-fat diet-induced obesity in male Wistar rats

Obesity (OBS) has been established as a link to male hypogonadism with consequent infertility. Previous studies have shown that melatonin (MEL) modulates hypothalamic-pituitary-gonadal function. The present study therefore investigated the hypothesis that MEL supplementation would attenuate spermatogenic and steroidogenic dysfunctions associated with obesity induced by high-fat diet (HFD). Twenty-four adult male Wistar rats (n = 6/group) were used: control group received vehicle (normal saline), obese group received 40% high-fat diet and distilled water, MEL-treated group received MEL (4 mg/kg), and OBS + MEL group received MEL and 40% HFD and the treatment lasted for 12 weeks. HFD caused increased body weight, glucose intolerance, plasma triglyceride and low-density lipoprotein cholesterol/ very low-density lipoprotein cholesterol and malondialdehyde, as well as decreased antioxidant capacity, high-density lipoprotein cholesterol, gonadotrophin-releasing hormone, follicle-stimulating hormone and testosterone and altered sperm parameters. However, all these alterations were attenuated when supplemented with MEL. Taken together, these results indicate that HFD exposure causes endocrine dysfunction and disrupted sperm parameters in obese animals, which are accompanied by lipid peroxidation/defective antioxidant capacity. In addition, the present results suggest that melatonin supplementation restores endocrine function and sperm integrity in obese rat model by suppression of oxidative stress-dependent mechanism.

Self-Instructional Training Application on Diabetic Patients' Self-Care Behaviors

Background: The diabetes mellitus cases have significantly increased in Indonesia over recent years. Health education for patients has often been carried out; however, education using self-instructional methods, which provided self-learning to solve problems by adjusting the patient's ability to improve self-care behaviors, has not been widely used.Purpose: This study aimed to analyze the self-care behaviors of diabetic patients with the application of self-instructional training.Methods: This research was a quasi-experimental study with a non-equivalent pretest-posttest with a control group design. The participants were 73 diabetic patients in the out-patient units selected by a purposive sampling technique, and divided into two groups: the intervention group (n=37) and the control group (n=36). The intervention group received a self-instructional training program which was carried out in two sessions using a booklet; each session lasted for 45 minutes. The Summary of Diabetes Self-Care Activities (SDSCA) questionnaire was used to collect diabetic patients' self-care behavior data. Wilcoxon and Mann-Whitney tests were employed for data analysis.Results: Self-care behaviors of patients with diabetes mellitus increased before and after the training in both groups (p=0.000). However, the increase in the intervention group was higher than that in the control group, from 46.46±5.014 to 58.03±7.320 and from 47.78±4.929 to 51.64±6.406, respectively. There was also a significant difference in the self-care behaviors of diabetic patients between the intervention group and the control group (p=0.000).Conclusion: Self-instructional training significantly improves self-care behaviors of diabetic patients. Therefore, self-instructional training can be considered to apply in the clinical setting for improving self-care behaviors of diabetic patients to prevent complications, and for enhancing nursing care of diabetes mellitus.

Male hypogonadism: therapeutic choices and pharmacological management

Male hypogonadism, defined as an inadequate testosterone production, recognizes a testicular (primary hypogonadism) or a hypothalamic-pituitary dysfunction (central hypogonadism), although combined forms can also occur. Moreover, it has been known that intensive exercise training might be a cause of functional hypogonadism. Many therapeutic choices are currently available, depending on the timing of hypogonadism onset and fertility issue. The aim of this review was to comprehensively supply therapeutic options and schemes currently available for male hypogonadism, including pharmacological management of primary and central forms. Evidence on testosterone formulations, human chorionic gonadotropin, selective estrogen receptor modulators and aromatase inhibitors will be provided.

Increase in testosterone levels is related to a lower risk of conversion of prediabetes to manifest diabetes in prediabetic males

Background

Testosterone plays an important role in the regulation of glucose metabolism. While earlier studies have shown that it has a protective effect in males, unfavorable effects of testosterone on glucose metabolism have been reported in females; however, whether there is a sex-specific relationship between testosterone and glucose metabolism in patients with prediabetes has not been investigated in detail hitherto.

Methods

This cross-sectional analysis investigated 423 males and 287 females with diagnosed prediabetes. Detailed assessment of their metabolic profiles was performed, including a 2‑h oral glucose tolerance test (OGTT), HbA1c levels, calculation of insulin resistance with homeostatic model assessment for insulin resistance (HOMA-IR), assessment of lipid metabolism, anthropometric parameters and the fatty liver index (FLI). By using Spearman’s correlation test, we investigated the sex-specific relationship between testosterone and metabolism in the prediabetic individuals.

Results

In the present study, prediabetic females (mean age 58.6 years, confidence interval [CI: 57.6 y; 59.5 y]) were characterized by lower fasting plasma glucose levels (104.2 mg/dl [CI: 103.0 mg/dl; 105.4 mg/dl] vs. 106.9 mg/dl [CI: 106.0 mg/dl; 107.8 mg/dl]) and a lower FLI (49.5 [CI: 45.7; 53.2] vs. 58.8 [CI: 55.8; 61.8]), but presented with a higher risk of developing manifest type 2 diabetes in the next 10 years (FINDRISK score: 17.6 [CI: 17.1; 18.1] vs. 16.1 [CI: 15.7; 16.5]) when compared to prediabetic males (mean age: 58.04 years [CI: 57.0 y; 59.1 y]). Testosterone was negatively related to insulin resistance (HOMA-IR: Spearman’s ρ: −0.33, p < 0.01), 2‑h stimulated glucose levels during the OGTT (ρ = −0.18, p < 0.01), HbA1c levels (ρ = −0.13, p < 0.05), FLI and BMI in prediabetic males; however, no relationship between testosterone and metabolic parameters could be found in prediabetic females.

Conclusion

The increase of testosterone levels in males was related to a more favorable glucose metabolism, including lower HbA1c, lower stimulated glucose levels and higher insulin sensitivity; however, in prediabetic females, testosterone was not related to glucose metabolism.

Fasting glucose level and all-cause or cause-specific mortality in Korean adults: a nationwide cohort study

BACKGROUND/AIMS

Although people with diabetes have been shown to have higher mortality than people without diabetes, there is a lack of data on the association between fasting glucose (FG) levels and cause-specific mortality rates in the general population.

METHODS

A total of 326,547 Korean adults over 20 years of age, who had received a health checkup between 2006 and 2008 were selected from the Korean National Health Insurance Service sample cohort dataset and followed until 2015. We estimated hazard ratios (HRs) of all-cause mortality and cause-specific mortality relative to various range of FG levels. All causes of death were classified according to International Classification of Diseases (ICD)-10 codes.

RESULTS

During follow-up (mean, 8.5 years), a total of 13,536 deaths (mortality rate 4.89/1,000 person-year) occurred; 4,916 deaths from cancer, 2,133 from cardiovascular disease, 762 from infectious disease, 199 from renal disease, and 5,526 from other causes. The overall mortality rate increased with an increase in FG category (HR, 1.78; 95% confidence interval, 1.65 to 1.92; in the ≥ 160 mg/dL). In addition, a J-shaped associations was found between FG levels and all-cause mortality after adjustment for age, sex, smoking, drinking, physical activity, body mass index, diabetes mellitus medication, hypertension, and dyslipidemia. In particular, the risk of cancer-mortality with high FG levels was increased for men but not women.

CONCLUSION

The risk of all-cause and cause-specific mortality showed the tendency to increase when the FG level was outside of the normal range, indicating a J-shaped relationship, in both men and women.

Testosterone replacement therapy in hypogonadal male patients with hypogonadism and heart failure: a meta-analysis of randomized controlled studies

BACKGROUND

The recently published guidelines of the European Academy of Andrology (EAA) recommended not to prescribe testosterone replacement therapy (TRT) in male patients with hypotestosteronemia and severe heart failure (HF) [New York Hearth Association (NYHA) class III and IV] since the risk in these patients has not been formally documented. Therefore, the aim of this study was to systematically evaluate the risk of TRT on the cardiac function and angina, in male patients with hypotestosteronemia and HF or coronary heart disease.

METHODS

Randomized controlled trials (RCTs) on male patients with hypotestosteronemia and chronic HF (ejection fraction <40%) or stable angina documenting the effect of TRT on NYHA class, left ventricula ejection fraction (LVEF), adverse events, ST depression and other indexes of cardiovascular function.

RESULTS

Seven articles were included, for a total of 140 participants with HF (71 on TRT and 69 on placebo or no treatment). Included patients were of NYHA class II and III. TRT had no effect on death and rehospitalization rates of patients with HF and significantly delayed the time to ischemia in patients with chronic angina. TRT had not effect on the NYHA class, the LVEF, and on the Minnesota Living with Heart Failure questionnaire. Although a significant increase of oxygen consumption was found in the TRT group, no improvement to the physical exercise tolerance tests was observed. TRT showed no effect on systolic nor diastolic blood pressure, but it significantly ameliorated the heart rate. It significantly decreased the insulin serum levels and the HOMA index.

CONCLUSIONS

These results suggest the safety of TRT, in patients with hypotestosteronemia and severe HF (class NYHA II and III). Although deriving from a limited number of studies, these data could prompt to perform other RCTs on the effects of TRT in patients with hypotestosteronemia and severe HFrEF (NYHA class III).

The Interaction of Insulin and Pituitary Hormone Syndromes

Pituitary hormone axes modulate glucose metabolism and exert direct or indirect effects on insulin secretion and function. Cortisol and growth hormone are potent insulin-antagonistic hormones. Therefore impaired glucose tolerance, elevated fasting glucose concentrations and diabetes mellitus are frequent in Cushing's disease and acromegaly. Also prolactinomas, growth hormone (GH) deficiency, hypogonadism and hypothyroidism might be associated with impaired glucose homeostasis but usually to a lesser extent. Therefore glucose metabolism needs to be closely monitored and treated in patients with pituitary adenomas. Correction of the pituitary dysfunction is frequently followed by improvement of glucose homeostasis.

Serum Vitamin D Affected Type 2 Diabetes though Altering Lipid Profile and Modified the Effects of Testosterone on Diabetes Status

Numerous studies have investigated the associations between serum vitamin D or testosterone and diabetes; however, inconsistencies are observed. Whether there is an interaction between vitamin D and testosterone and whether the lipid profile (total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)) mediates the association between vitamin D and diabetes is unclear. To investigate the effect of vitamin D and testosterone on impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM), 2659 participants from the Henan Rural Cohort were included in the case-control study. Generalized linear models were utilized to estimate associations of vitamin D with IFG or T2DM and interactive effects of vitamin D and testosterone on IFG or T2DM. Principal component analysis (PCA) and mediation analysis were used to estimate whether the lipid profile mediated the association of vitamin D with IFG or T2DM. Serum 25(OH)D₃, 25(OH)D₂, and total 25(OH)D levels were negatively correlated with IFG (odds ratios (ORs) (95% confidence intervals (CIs)): 0.99 (0.97, 1.00), 0.85 (0.82, 0.88), and 0.97 (0.96, 0.98), respectively). Similarity results for associations between serum 25(OH)D₂ and total 25(OH)D with T2DM (ORs (95%CIs): 0.84 (0.81, 0.88) and 0.97 (0.96, 0.99)) were observed, whereas serum 25(OH)D₃ was negatively correlated to T2DM only in the quartile 2 (Q2) and Q3 groups (both p < 0.05). The lipid profile, mainly TC and TG, partly mediated the relationship between 25(OH)D₂ or total 25(OH)D and IFG or T2DM and the proportion explained was from 2.74 to 17.46%. Furthermore, interactive effects of serum 25(OH)D₂, total 25(OH)D, and testosterone on T2DM were observed in females (both p for interactive <0.05), implying that the positive association between serum testosterone and T2DM was vanished when 25(OH)D₂ was higher than 10.04 ng/mL or total 25(OH)D was higher than 40.04 ng/mL. Therefore, ensuring adequate vitamin D levels could reduce the prevalence of IFG and T2DM, especially in females with high levels of testosterone.

Testosterone treatment longer than 1 year shows more effects on functional hypogonadism and related metabolic, vascular, diabetic and obesity parameters (results of the 2-year clinical trial)

OBJECTIVE

We evaluated long-term effects of testosterone undecanoate on glycemic control, metabolic syndrome, vascular function and morphology in obese men with functional hypogonadism (FH) and type 2 diabetes (T2D) in a 2-year prospective clinical trial.

METHODS

A total of 55 participants were enrolled in this study; group P (n = 27) received placebo during first and testosterone therapy (TTh) during second year, group T (n = 28) received TTh both years. We pooled results after 1 year of TTh to obtain more statistical power. Results for group T after 2 years of TTh are also presented. We evaluated wide assortment of biochemical (fasting plasma glucose-FPG, glycated hemoglobin-HbA1c and lipid profile), hormonal, vascular (flow-mediated dilatation-FMD and intima-media thickness-IMT), anthropometrical and derived parameters (BMI, HOMA-IR, non-HDL cholesterol, bioavailable and calculated free testosterone). Quality of life was assessed using Aging Males' Symptoms (AMS) questionnaire.

RESULTS

FPG, HbA₁c, HOMA-IR and IMT decreased, FMD increased, lipid profile and AMS sexual sub-score improved, and testosterone levels fully normalized after 2 years of TTh.

CONCLUSIONS

Two-year of TTh resulted in normalized serum testosterone levels, improved glycemia, endothelial function, lipids and insulin sensitivity, and quelled the symptoms of hypogonadism, potentially reducing cardiovascular risk in obese men with FH and T2D.

Prevalence of hypogonadism in patients with type 2 diabetes mellitus among the Indian population

OBJECTIVES

To determine the prevalence of hypogonadism among Indian men with and without type 2 diabetes mellitus (T2DM) and evaluate its association with various metabolic parameters.

METHODS

One hundred fifty consecutive men with T2DM, aged 25-70 years, and one hundred age-matched healthy men without diabetes were included. The free testosterone (FT) level was calculated using the total testosterone (TT), sex hormone-binding globulin (SHBG), and albumin levels in serum. Patients with a calculated FT level <6.35 ng/dL and a positive response on the androgen deficiency in aging male questionnaire (ADAM) were diagnosed with hypogonadism.

RESULTS

The prevalence of hypogonadism was 17.3% and 10% in men with and without T2DM, respectively. The body mass index (BMI) and the mean levels of follicle-stimulating hormone (FSH), TT, SHBG, Triglycerides (TG), and FT were significantly different between the groups. The mean BMI and TG levels were significantly higher in patients with T2DM than in those without. Both groups showed a significant negative correlation between the BMI and SHBG level.

CONCLUSION

The hypogonadism prevalence was higher in patients with T2DM than in those without, although the difference did not reach statistical significance.

The Potential Effect of Aberrant Testosterone Levels on Common Diseases: A Mendelian Randomization Study

Testosterone has historically been linked to sexual dysfunction; however, it has recently been shown to affect other physical and mental attributes. We attempted to determine whether changes in serum testosterone could play a role in chronic or degenerative diseases. We used two separate genetic instruments comprising of variants from JMJD1C and SHBG regions and conducted a two-sample Mendelian randomization for type II diabetes (T2D), gout, rheumatoid arthritis (RA), schizophrenia, bipolar disorder, Alzheimer's disease and depression. For the JMJD1C locus, one unit increase in log transformed testosterone was significantly associated with RA (OR = 1.69, p = 0.02), gout (OR = 0.469, p = 0.001) and T2D (OR = 0.769, p = 0.048). Similarly, one unit increase in log transformed testosterone using variants from the SHBG locus was associated with depression (OR = 1.02, p < 0.0001), RA (OR = 1.254, p < 0.0001) and T2D (OR = 0.88, p < 0.0001). Our results show that low levels of serum testosterone levels may cause gout and T2D, while higher than normal levels of testosterone may result in RA and depression. Our findings suggest that fluctuations in testosterone levels may have severe consequences that warrant further investigation.

The Effects of Androgens on Cardiometabolic Syndrome: Current Therapeutic Concepts

INTRODUCTION

Cardiometabolic syndrome (CMS), as a bunch of metabolic disorders mainly characterized by type 2 diabetes mellitus (T2DM), hypertension, atherosclerosis, central adiposity, and abdominal obesity triggering androgen deficiency, is one of the most critical threats to men. Although many significant preclinical and clinical findings explain CMS, new approaches toward common pathophysiological mechanisms and reasonable therapeutic targets are lacking.

AIM

To gain a further understanding of the role of androgen levels in various facets of CMS such as the constellation of cardiometabolic risk factors including central adiposity, dyslipidemia, insulin resistance, diabetes, and arterial hypertension and to define future directions for development of effective therapeutic modalities.

METHODS

Clinical and experimental data were searched through scientific literature databases (PubMed) from 2009 to October 2019.

MAIN OUTCOME MEASURE

Evidence from basic and clinical research was gathered with regard to the causal impact and therapeutic roles of androgens on CMS.

RESULTS

There are important mechanisms implicated in androgen levels and the risk of CMS. Low testosterone levels have many signs and symptoms on cardiometabolic and glycometabolic risks as well as abdominal obesity in men.

CLINICAL IMPLICATIONS

The implications of the findings can shed light on future improvements in androgen levels and add potentially predictive risk for CMS, as well as T2DM, abdominal obesity to guide clinical management in the early stage.

STRENGTHS & LIMITATIONS

This comprehensive review refers to the association between androgens and cardiovascular health. A limitation of this study is the lack of large, prospective population-based studies that analyze the effects of testosterone treatment on CMS or mortality.

CONCLUSION

Low testosterone levels have several common features with metabolic syndrome. Thus, testosterone may have preventive role in the progress of metabolic syndrome and subsequent T2DM, abdominal obesity, and cardiovascular disease and likely affect aging men's health mainly through endocrine and vascular mechanisms. Further studies are necessary to evaluate the therapeutic interventions directed at preventing CMS in men. Kirlangic OF, Yilmaz-Oral D, Kaya-Sezginer E, et al. The Effects of Androgens on Cardiometabolic Syndrome: Current Therapeutic Concepts. Sex Med 2020;8:132-155.

Testosterone deficiency in men with Type 2 diabetes: pathophysiology and treatment

Epidemiological studies consistently demonstrate that lowered serum testosterone is not only common in men with established Type 2 diabetes, but also predicts future diabetic risks and increased mortality. Preclinical studies report plausible mechanisms by which low testosterone could mediate dysglycaemia. Exogenous testosterone treatment consistently reduces fat mass, increases muscle mass and improves insulin resistance in some studies, but the majority of currently available randomized controlled trials (RCTs) do not report a consistent glycaemic benefit. In men with diabetes, testosterone treatment effects on androgen deficiency-like clinical features are inconsistent, and effects on sexual dysfunction may be attenuated compared with men without diabetes. The long-term risks of testosterone treatment in older men without medical disease of the hypothalamic-pituitary-testicular axis are not known. Current RCTs are not definitive, owing to their small size, short duration and enrolment of men with mostly relatively good baseline glycaemic control not specifically selected for the presence of androgen deficiency symptoms. Although large, well-designed clinical trials are needed, given the benefit-risk ratio of testosterone treatment is not well understood, routine serum testosterone testing or testosterone treatment of asymptomatic men with Type 2 diabetes is currently not recommended. Carefully selected, symptomatic men with low testosterone who are informed of the lack of high-level evidence regarding the long-term benefits and risks of this approach may be offered a trial of testosterone treatment in combination with lifestyle measures, weight loss and optimization of comorbidities.

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.

A New LC-MS/MS Method for Simultaneous and Quantitative Detection of Bisphenol-A and Steroids in Target Tissues: A Power Tool to Characterize the Interference of Bisphenol-A Exposure on Steroid Levels

Bisphenol A (BPA), an endocrine disruptor, may affect in situ steroidogenesis and alter steroids levels. The present work proposes a liquid chromatography tandem mass spectrometry method to simultaneously quantify BPA, 17β-Estradiol and testosterone in two target tissues: testis and visceral fat mass. Analytes were isolated and lipophilic impurities removed by two serial steps: liquid-liquid and solid phase extraction. All compounds were separated in a single gradient run by Kinetex F5 column and detected via multiple reaction monitoring using a triple quadrupole with a TurboIon electrospray source in both negative and positive modes. The method is selective and very sensitive. In the investigated concentration range, the linearity of the detector response is verified in both tissues. The use of specific SPE cartridges for affinity chromatography purification allows obtaining high percentages of process efficiency (68.0-83.3% for testicular tissue; 63.7-70.7% for visceral fat mass). Good repeatability and reproducibility was observed. The validated method can be efficiently applied for direct biological monitoring in testis and visceral fat mass from mice exposed to BPA. The quantification of compounds in a single assay could be achieved without a loss of sensitivity.

Obesity and male hypogonadism: Tales of a vicious cycle

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

Male Obesity-related Secondary Hypogonadism - Pathophysiology, Clinical Implications and Management

The single most significant risk factor for testosterone deficiency in men is obesity. The pathophysiological mechanisms involved in male obesity-related secondary hypogonadism are highly complex. Obesity-induced increase in levels of leptin, insulin, proinflammatory cytokines and oestrogen can cause a functional hypogonadotrophic hypogonadism with the defect present at the level of the hypothalamic gonadotrophin-releasing hormone (GnRH) neurons. The resulting hypogonadism by itself can worsen obesity, creating a self-perpetuating cycle. Obesity-induced hypogonadism is reversible with substantial weight loss. Lifestyle-measures form the cornerstone of management as they can potentially improve androgen deficiency symptoms irrespective of their effect on testosterone levels. In selected patients, bariatric surgery can reverse the obesity-induced hypogonadism. If these measures fail to relieve symptoms and to normalise testosterone levels, in appropriately selected men, testosterone replacement therapy could be started. Aromatase inhibitors and selective oestrogen receptor modulators are not recommended due to lack of consistent clinical trial-based evidence.

Association of serum testosterone with different classes of glucose metabolism and the mediation effect of obesity: The Henan Rural Cohort Study

AIMS

We aimed to investigate the association of serum testosterone with impaired fasting glucose (IFG) and type 2 diabetes mellitus (T2DM) and calculate the proportion explained by obesity status on the relationship.

MATERIALS AND METHODS

A case-control study including 2775 participants was performed. Serum testosterone was quantified by liquid chromatography-tandem mass spectrometry. Conditional logistic regression and multivariable linear regression were performed to estimate the relationships between testosterone and different glucose status. Waist circumference (WC) was used as a mediator to estimate the mediation effect.

RESULTS

After adjusting for multiple variables, serum testosterone levels were negatively associated with T2DM in males (per 1 unit natural log-transformed, odd ratio (OR) = 0.73, 95% confidence interval (CI): 0.56, 0.96; Tertile 3 vs Tertile 1, OR = 0.46, 95% CI:0.29, 0.72) while were positively in females (per 1 unit natural log-transformed, OR = 1.56, 95% CI:1.32, 1.84; Tertile 3 vs Tertile 1, OR = 3.55, 95% CI: 2.22, 5.66). In males, a higher testosterone tended to be associated with a lower fasting plasma glucose level and a weaker HOMA2-IR but a stronger HOMA2-β. Opposite findings were observed in females. Furthermore, WC played a full and partial mediating role in the relationship between testosterone and IFG and T2DM both in males and females.

CONCLUSION

Serum testosterone levels had opposite effects on IFG and T2DM in males and females. With higher serum testosterone levels, the dysglycemia progression was decreased among males while increased among females. In addition, WC played a full and partial mediating role in the relationship between testosterone and IFG and T2DM.

Analysis of cardiovascular risk factors associated with serum testosterone levels according to the US 2011-2012 National Health and Nutrition Examination Survey

OBJECTIVE

To investigate associations between cardiovascular disease risk factors, including fasting glucose, cholesterol, high density lipoprotein cholesterol (HDL-c), LDL-c, blood pressure, body mass index (BMI), C-peptide, creatinine kinase, smoking, alcohol use, physical activity, C-reactive protein as well as homocysteine levels and cardiovascular events.

METHODS

Data from 1545 men aged ≥40 years, with testosterone deficiency (TD) (<300 ng/dL) and non-TD (≥300 ng/dL) which were extracted from the National Health and Nutrition Examination Survey database 2011-2012 and analyzed.

RESULTS

Multivariate logistic regression analysis showed positive associations between TD and BMI (≥35 vs. < 18.5: OR = 2.51, 95% CI: 1.19-5.32, p = .016), HDL-c (<0.91 vs. ≥0.91: OR = 1.60, 95% CI: 1.14-2.24, p = .006) and diabetes (diabetes vs. non-diabetes: OR = 1.48, 95% CI: 1.14-1.92, p = .004) as well as negative associations between TD and metabolic equivalent scores (≥12 vs. <12: OR = 0.69, 95% CI: 0.52-0.91, p = .009) and smoking (Ever vs. never: OR = 0.69, 95% CI: 0.51-0.94, p = .018). Furthermore, total serum testosterone levels were lower in patients with heart failure (p = .04) and angina/angina pectoris (p = .001) compared with subjects without these cardiac problems.

CONCLUSION

Low serum testosterone was associated with multiple risk factors for CHD.

The association between fasting plasma glucose and all-cause and cause-specific mortality by gender: The rural Chinese cohort study

BACKGROUND

To evaluate the association between fasting plasma glucose (FPG) and mortality by gender.

METHODS

A total of 17 248 eligible participants from a rural Chinese prospective cohort population were included. The same questionnaire interview and anthropometric and laboratory measurements were performed at both baseline (2007-2008) and follow-up (2013-2014). Participants were classified according to baseline FPG and diabetic status by sex. Restricted cubic splines and Cox proportional-hazards regression models, estimating hazard ratio (HR) and 95% confidence interval (CI), were used to assess the FPG-mortality relation.

RESULTS

During the 6-year follow-up, 618 men and 489 women died. The FPG-mortality relation was J shaped for both sexes. For men, risk of all-cause and noncardiovascular disease (CVD)/noncancer mortality was greater with low fasting glucose (LFG) than with normal fasting glucose (adjusted HR [aHR] 1.60; 95% CI, 1.05-2.43; and aHR 2.16; 95% CI, 1.15-4.05). Men with diabetes mellitus (DM) showed increased risk of all-cause (aHR 2.04; 95% CI, 1.60-2.60), CVD (aHR 1.98; 95% CI, 1.36-2.89), and non-CVD/noncancer mortality (aHR 2.62; 95% CI, 1.76-3.91). Men with impaired fasting glucose (IFG) had borderline risk of CVD mortality (aHR 1.34; 95% CI, 1.00-1.79). Women with LFG had increased risk of non-CVD/noncancer mortality (aHR 2.27; 95% CI, 1.04-4.95), and women with DM had increased risk of all-cause (aHR 1.73; 95% CI, 1.35-2.23), CVD (aHR 1.76; 95% CI, 1.24-2.50), and non-CVD/noncancer mortality (aHR 1.97; 95% CI, 1.27-3.08).

CONCLUSIONS

LFG is positively associated with all-cause mortality risk in rural Chinese men but not in women.

Is there a potential association between spironolactone and the risk of new-onset diabetes in a cohort of older patients with heart failure?

PURPOSE

Some evidence suggests that spironolactone may have a deleterious effect on glucose homeostasis. The objective of this study was to assess whether spironolactone use is associated with a higher risk of developing diabetes in a large cohort of patients with heart failure (HF).

METHODS

Two Quebec government administrative databases were used to identify a cohort of hospitalized patients discharged between January 1995 and December 2009 with a primary discharge diagnosis of HF and without secondary discharge diagnosis of diabetes. Patients were categorized as new users of spironolactone and non-users. The primary outcome was defined as new-onset diabetes (NOD) during 5 years of follow-up and was ascertained using ICD codes for diabetes or use of hypoglycemic agents.

RESULTS

Among the 2974 patients that were included in the cohort analysis, 769 were given a new prescription of spironolactone. The incidence rate of NOD was similar among spironolactone users (5.0 per 100 person-years) and non-users (4.9 per 100 person-years). There was no significant association between the use of spironolactone and NOD in the crude, unadjusted model (hazard ratio (HR) 1.01; 95% confidence interval (CI) 0.80-1.28; p = 0.9217), and it remained unchanged in the adjusted Cox proportional hazard model (HR = 0.92; 95% CI = 0.72-1.18; p = 0.5227). The results were consistent with those observed in sensitivity analyses of a 1:3 propensity score-matched cohort (HR = 0.97; CI = 0.76-1.25; p = 0.8169).

CONCLUSION

We found no evidence supporting the claim that use of spironolactone is associated with a higher risk of diabetes among patients hospitalized for HF.

The association between serum testosterone and insulin resistance: a longitudinal study

The objective of this study was to investigate whether there is a bidirectional association between testosterone concentrations and insulin resistance, in a prospective population study. A random population sample of 1400 men, aged 30-74, was examined in 2002-2005 in southwestern Sweden and followed up in 2012-2014 (N = 657). After excluding subjects without information on sex hormones and insulin resistance, 1282 men were included in the baseline study. Fasting measurements of plasma glucose, insulin and hormones were performed. Insulin resistance was defined using HOMA-Ir. Mean age at baseline was 47.3 ± 11.4 years. From the follow-up survey 546 men were included, mean age 57.7 ± 11.6 years. Low concentrations of total testosterone at baseline were significantly associated with high logHOMA-Ir at follow-up in a multivariable model including age, waist-hip ratio, physical activity, alcohol intake, smoking, LDL, CRP, hypertension, diabetes and logHOMA-Ir at baseline as covariates (β = -0.096, P = 0.006). Similar results were observed for bioavailable testosterone. Men within the lowest quartile of total testosterone at baseline had significantly higher logHOMA-Ir at follow-up than other quartiles (Q1 vs Q2 P = 0.008, Q1 vs Q3 P = 0.001, Q1 vs Q4 P = 0.052). Multivariable analysis of the impact of insulin resistance at baseline on testosterone levels at follow-up revealed no significant associations regarding testosterone concentrations (β = -0.003, P = 0.928) or bioavailable testosterone (β = -0.006, P = 0.873), when adjusting for baseline concentrations of total testosterone, age, waist-hip-ratio, LDL, CRP, physical activity, alcohol intake, smoking, hypertension and diabetes. Low testosterone concentrations at baseline predicted higher insulin resistance at follow-up, but high insulin resistance at baseline could not predict low testosterone at follow-up.

Testosterone-Associated Dietary Pattern Predicts Low Testosterone Levels and Hypogonadism

Obesity and low serum testosterone (T) levels are interrelated and strongly influenced by dietary factors, and their alteration entails a great risk of hypogonadism. Substantial evidence suggests a bidirectional relationship between nutrient metabolism (e.g., glucose, lipids, and iron) and T levels in men; however, T-related dietary patterns remain unclear. This study investigated the dietary patterns associated with serum total T levels and its predictive effect on hypogonadism and the body composition. Anthropometry, blood biochemistry, and food frequency questionnaires were collected for 125 adult men. Dietary patterns were derived using a reduced rank regression from 32 food groups. Overall prevalence rates of central obesity and hypogonadism were 48.0% and 15.7%, respectively. An adjusted linear regression showed that age, insulin, red blood cell (RBC) aggregation, and transferrin saturation independently predicted serum total T levels (all p < 0.01). The total T-related dietary pattern (a high consumption of bread and pastries, dairy products, and desserts, eating out, and a low intake of homemade foods, noodles, and dark green vegetables) independently predicted hypogonadism (odds ratio: 5.72; 95% confidence interval: 1.11‒29.51, p < 0.05) for those with the highest dietary pattern scores (Q4) compared to those with the lowest (Q1). Scores were also negatively correlated with the skeletal muscle mass (p for trend = 0.002) but positively correlated with the total body fat mass (p for trend = 0.002), visceral fat mass (p for trend = 0.001), and to a lesser extent, subcutaneous fat mass (p for trend = 0.035) after adjusting for age. Randomized controlled trials are needed to confirm that improvement in dietary pattern can improve T levels and reduce hypogonadism.

The impact of testosterone replacement therapy on glycemic control, vascular function, and components of the metabolic syndrome in obese hypogonadal men with type 2 diabetes

OBJECTIVE

This study set out to assess effects of testosterone replacement therapy (TRT) on parameters of metabolic syndrome and vascular function in obese hypogonadal males with type 2 diabetes mellitus (DM2).

STUDY DESIGN

Fifty-five obese hypogonadal diabetic males on oral hypoglycemic treatment were enrolled into this one-year, double-blind, randomized, placebo-controlled clinical study. Group T (n = 28) was treated with testosterone undecanoate (1000 mg i.m. every 10 weeks) while group P (n = 27) received placebo.

METHODS

Anthropometrical and vascular measurements - flow-mediated dilatation (FMD) and intima media thickness (IMT) - biochemical and hormonal blood sample analyses were performed at the start of the study and after one year. Derived parameters (BMI, HOMA-IR, calculated free testosterone (cFT) and bioavailable testosterone (BT)) were calculated.

RESULTS

TRT resulted in reduction of HOMA-IR by 4.64 ± 4.25 (p < .001), HbA1c by 0.94 ± 0.88% points (p < .001), and an increase in FMD by 2.40 ± 4.16% points (p = .005).

CONCLUSION

TRT normalized serum testosterone levels, improved glycemic control and endothelial function while exerting no ill effects on the study population.

The complex association between metabolic syndrome and male hypogonadism

BACKGROUND

The complex association between metabolic syndrome (MetS) and male hypogonadism is well established. A number of observational studies show that low testosterone is associated with insulin resistance and an increased risk for diabetes mellitus and MetS in men.

AIMS

To elucidate the association between MetS and male hypogonadism, present epidemiological data on the co-existence of the two comorbidities, enlighten the underlying pathophysiology and appraise the effects of testosterone supplementation therapy (TTh) and lifestyle modifications on MetS and body composition in men.

MATERIALS AND METHODS

Systematic search to PubMed and Medline databases for publications reporting data on association between MetS and male hypogonadism.

RESULTS

Both MetS and male hypogonadism have a high prevalence in the general population and are frequently co-existing e.g. in males with diabetes. Accumulating evidence from animal and human studies suggests that MetS is involved in the pathogenesis of hypogonadism in males as well as the other way around. On the other hand, there is evidence for a favorable effect of testosterone supplementation in testosterone deficient men with MetS and/or diabetes mellitus.

CONCLUSIONS

Studies with superior methodological characteristics are needed in order to establish a role for testosterone supplementation in men with MetS and/or diabetes mellitus.

Testosterone Levels and Type 2 Diabetes-No Correlation with Age, Differential Predictive Value in Men and Women

Most studies reporting on the association of circulating testosterone levels with type 2 diabetes in men are of cross-sectional design. Reports on the relevance of altered testosterone levels in women are scarce. Here, we evaluate the role of low serum testosterone levels for incident diabetes in men and women in a population setting of 7706 subjects (3896 females). During a mean follow up time of 13.8 years, 7.8% developed type 2 diabetes. Significant correlations of testosterone with high density lipoprotein (HDL)-cholesterol (R = 0.21, p < 0.001), body-mass-index (R = −0.23, p < 0.001), and waist-to-hip-ratio (R = −0.21, p < 0.001) were found in men. No correlation was found with age in men; in women, the correlation was negligible (R = 0.04, p = 0.012). In men, low testosterone levels predicted high risk of type 2 diabetes, while in women this relationship was opposite. Men with low testosterone levels showed increased risk of future diabetes (hazard ratio (HR) 2.66, 95% confidence interval (CI) 1.91–3.72, p < 0.001 in basic model; HR 1.56 95%, CI 1.10–2.21, p = 0.003). In women, low testosterone levels indicated lower risk with (HR 0.53, 95% CI 0.37–0.77, p = 0.003), while the association lost significance in the fully adjusted model (HR 0.72, 95% CI 0.49–1.05, p = 0.09). Low levels of testosterone predicted future diabetes in men. A borderline opposite association was found in women.

Hypogonadism and male obesity: Focus on unresolved questions

Obesity, increasing in prevalence globally, is the clinical condition most strongly associated with lowered testosterone concentrations in men and presents as one of the strongest predictors of receiving testosterone treatment. While low circulating total testosterone concentrations in modest obesity primarily reflect reduced concentrations of sex hormone binding globulin, more marked obesity can lead to genuine hypothalamic-pituitary-testicular axis (HPT) suppression. HPT axis suppression is likely mediated via pro-inflammatory cytokine and dysregulated leptin signalling and aggravated by associated comorbidities. Whether oestradiol-mediated negative hypothalamic-pituitary feedback plays a pathogenic role requires further study. Although the obesity-hypogonadism relationship is bidirectional, the effects of obesity on testosterone concentrations are more substantial than the effects of testosterone on adiposity. In markedly obese men submitted to bariatric surgery, substantial weight loss is very effective in reactivating the HPT axis. In contrast, lifestyle measures are less effective in reducing weight and generally only associated with modest increases in circulating testosterone. In randomized controlled clinical trials (RCTs), testosterone treatment does not reduce body weight, but modestly reduces fat mass and increases muscle mass. Short-term studies have shown that testosterone treatment in carefully selected obese men may have modest benefits on symptoms of androgen deficiency and body composition even additive to diet alone. However, longer term, larger RCTs designed for patient-important outcomes and potential risks are required. Until such trials are available, testosterone treatment cannot be routinely recommended for men with obesity-associated nonclassical hypogonadism. Lifestyle measures or where indicated bariatric surgery to achieve weight loss, and optimization of comorbidities remain first line.

The Relationship Between Health-Related Quality of Life and Anabolic Hormone Levels in Middle-Aged and Elderly Men With Prediabetes: A Cross-Sectional Study

The aim of this study was to compare health-related quality of life (HRQoL) between men with prediabetes (PD) and a control group as well as to investigate the relationship between HRQoL and anabolic hormones. The analysis was carried out in 176 middle-aged (40–59 years) and elderly (60 80 years) men with PD, and 184 control peers. PD was defined according the American Diabetes Association and HRQoL was assessed by the SF-36 questionnaire. Total testosterone (TT), calculated free testosterone, dehydroepiandrosterone sulfate (DHEAS), and insulin-like growth factor 1 (IGF-1) were measured. Analysis of the standardized physical and mental component summary scores (SF-36_p and SF-36_m) revealed that patients with PD had lower SF-36_p and SF-36_m than control group (p < .02 and p < .001). Middle-aged men with PD had lower SF-36_p and SF-36_m than control peers, whereas elderly men with PD had lower only SF-36_p. In men with PD negative correlations between glycated hemoglobin (HbA1c) and SF-35_m score (r = −0.3768; p = .02) and between HbA1c and SF-36_p score (r = −0.3453; p = .01) were reported. In middle-aged prediabetic men, SF-36_p was associated with high free testosterone and low HbA1c while SF-36_m with high TT and high DHEAS. In elderly patients with PD, SF-36_p was associated with high TT, high IGF-1, and low HbA1c, while SF-36_m correlated with high free testosterone and high DHEAS. In conclusion, PD in men is associated with decreased HRQoL in comparison with healthy men, and generally better quality of life is associated with higher testosterone, higher free testosterone, higher DHEAS, and lower HbA1c.

Testosterone Therapy and Glucose Homeostasis in Men with Testosterone Deficiency (Hypogonadism)

Since the early 1990s, it has been recognized that testosterone (T) levels are lower in men with type 2 diabetes mellitus (T2DM) compared with nondiabetic men (controls). Hypogonadism has been reported in approximately 50% of men with T2DM with robust correlations with measures of obesity, such as waist circumference and body mass index (BMI). In longitudinal studies, hypogonadism has been identified as a predictor of incident T2DM. Experimental withdrawal of T led to acute decreased insulin sensitivity, which can be reversed by normalization of T concentrations. Androgen deprivation therapy, commonly used in men with advanced prostate cancer, increases the risk of incident T2DM significantly.While short-term studies of T therapy in hypogonadal men with T2DM show only minor effects, long-term administration of T leads to meaningful and sustained improvements of glycemic control with parallel reductions in body weight and waist circumference. The more insulin-resistant and obese a patient is at the time of initiation of T therapy, the more improvements are noted. The observed effects are likely mediated by the increase in lean body mass invariably achieved by T therapy, as well as the improvement in energy and motivation, referred to as the psychotropic effects of T. As recommended by various guidelines, measuring T levels and, if indicated, restoring men's T levels into the normal physiological range can have a substantial impact on ameliorating T2DM in hypogonadal men.

Long-Term Testosterone Administration on Insulin Sensitivity in Older Men With Low or Low-Normal Testosterone Levels

Background

Serum testosterone levels and insulin sensitivity both decrease with age. Severe testosterone deficiency is associated with the development of insulin resistance. However, the effects of long-term testosterone administration on insulin sensitivity in older men with low or low-normal testosterone levels remain unknown.

Methods

The Testosterone Effects on Atherosclerosis in Aging Men Trial was a placebo-controlled, randomized, double-blind trial. The participants were 308 community-dwelling men, ≥60 years old, with total testosterone 100 to 400 ng/dL or free testosterone <50 pg/mL. A subset of 134 nondiabetic men (mean age, 66.7 ± 5.1 years) underwent an octreotide insulin suppression test at baseline and at 3 and 36 months after randomization to measure insulin sensitivity. Insulin sensitivity was estimated as the steady-state plasma glucose (SSPG) concentration at equilibrium during octreotide and insulin administration. Secondary outcomes included total lean mass (TLM) and total fat mass (TFM) by dual energy x-ray absorptiometry.

Results

There was a significant (P = 0.003) increase in SSPG in the placebo group, whereas no change was seen in testosterone-treated subjects from baseline to 36 months; however, the between-group differences in change in SSPG over 3 years were not statistically significant (+15.3 ± 6.9 mg/dL in the placebo group vs +6.2 ± 6.4 mg/dL in the testosterone group; mixed-model effect, P = 0.17). Changes in SSPG with testosterone treatment were not associated with changes in serum total or free testosterone concentrations. Changes in TFM but not TLM were associated with increases in SSPG. Stratification by age or baseline total testosterone level did not show significant intervention effects.

Conclusion

Testosterone administration for 36 months in older men with low or low-normal testosterone levels did not improve insulin sensitivity.

Metformin, Asian ethnicity and risk of prostate cancer in type 2 diabetes: a systematic review and meta-analysis

Background

Metformin is associated with a reduced risk of some cancers but its effect on prostate cancer is unclear. Some studies suggest only Asians derive this benefit. Therefore, we undertook a systematic review with particular attention to ethnicity.

Methods

Medline, Embase, Scopus, Web of Science, and EBM Reviews were searched from inception to 2015. Two reviewers identified and abstracted articles. Studies were pooled using random effects model and stratified by Western- vs Asian-based populations.

Results

We identified 482 studies; 26 underwent full review. Of Western-based studies (n = 23), two were randomized trials and 21 were observational studies. All Asian-based studies (n = 3) were observational. There were 1,572,307 patients, 1,171,643 Western vs 400,664 Asian. Across all studies there was no association between metformin and prostate cancer (RR: 1.01, 95%CI: 0.86-1.18, I²: 97%), with similar findings in Western-based trials (RR: 1.38, 95%CI: 0.72-2.64 I²: 15%) and observational studies (RR: 1.03 95%CI: 0.94-1.13, I²: 88%). Asian-based studies suggested a non-significant reduction (RR: 0.75, 95%CI: 0.42-1.34, I²: 90%), although these results were highly influenced by one study of almost 400,000 patients (propensity-adjusted RR: 0.47 95%CI 0.45-0.49). Removing this influential study yielded an estimate more congruent with Western-based studies (RR: 0.98 95%CI:0.71-1.36, I²: 0%).

Conclusion

There is likely no association between metformin and risk of prostate cancer, in either Western-based or Asian-based populations after removing a highly influential Asian-based study.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3934-9) contains supplementary material, which is available to authorized users.

Testosterone level and risk of type 2 diabetes in men: a systematic review and meta-analysis

BACKGROUND

Type 2 diabetes is a risk factor for testosterone deficiency and impaired sex steroid status. Some studies also investigated the association of testosterone level with diabetes risk in men, but reported controversial findings. To clarify this issue, we conducted a systematic review and meta-analysis.

METHODS

PubMed, EMBASE and Web of Science were searched for eligible cohort or nested case-control studies published up to August 15, 2017. Meta-analysis was used to calculate the pooled relative risk (RR) of type 2 diabetes associated with higher testosterone level.

RESULTS

Thirteen cohort or nested case-control studies with 16,709 participants were included. Meta-analysis showed that higher total testosterone level could significantly decrease the risk of type 2 diabetes in men (RR = 0.65; 95% CI 0.50-0.84; P = 0.001), and higher free testosterone level could also decrease the risk of type 2 diabetes in men (RR = 0.94; 95% CI 0.90-0.99; P = 0.014). After excluding two studies that did not calculate RRs by quartiles of testosterone levels, both higher total testosterone and free testosterone levels could decrease the risk of type 2 diabetes in men, and the pooled RRs were 0.62 (95% CI 0.51-0.76; P < 0.001) and 0.77 (95% CI 0.61-0.98; P = 0.03), respectively.

CONCLUSION

This meta-analysis suggests that higher testosterone level can significantly decrease the risk of type 2 diabetes in men. Therefore, combined with previous researches, the findings above suggest a reverse-causality scenario in the relation between testosterone deficiency and risk of type 2 diabetes in men.

Neuroactive steroids and diabetic complications in the nervous system

Important complications of diabetes mellitus in the nervous system are represented by diabetic peripheral neuropathy and diabetic encephalopathy. In this context, an important link is represented by neuroactive steroids (i.e., steroids coming from peripheral glands and affecting nervous functionality as well as directly synthesized in the nervous system). Indeed, diabetes does not only affect the reproductive axis and consequently the levels of sex steroid hormones, but also those of neuroactive steroids. Indeed, as will be here summarized, the levels of these neuromodulators present in the central and peripheral nervous system are affected by the pathology in a sex-dimorphic way. In addition, some of these neuroactive steroids, such as the metabolites of progesterone or testosterone, as well as pharmacological tools able to increase their levels have been demonstrated, in experimental models, to be promising protective agents against diabetic peripheral neuropathy and diabetic encephalopathy.

A systematic review and meta-analysis of the impact of mineralocorticoid receptor antagonists on glucose homeostasis

BACKGROUND

Spironolactone, a nonselective mineralocorticoid receptor antagonist (MRA), may have a deleterious effect on glycemia. The objective of this review was to assess current knowledge on MRAs' influence (spironolactone, eplerenone, and canrenone) on glucose homeostasis and the risk of diabetes.

METHOD

A systematic review was conducted using the Medline database on articles published from 1946 to January 2017 that studied the effects of MRAs on any glucose-related endpoints, without any restrictions regarding the participants' characteristics.Study design, patient population, dose and duration of intervention, and the quantitative results on glycemic markers were extracted, interpreted for result synthesis, and evaluated for sources of bias. From the articles included in the qualitative analysis, a select number were used in a meta-analysis on studies having measured glycated hemoglobin (HbA1c) or risk of diabetes.

RESULTS

Seventy-two articles were selected from the Medline database and references of articles. Results on spironolactone were heterogeneous, but seemed to be disease-specific. A potential negative effect on glucose regulation was mainly observed in heart failure and diabetes trials, while a neutral or positive effect was detected in diseases characterized by hyperandrogenism, and inconclusive for hypertension. Interpretation of data from heart failure trials was limited by the small number of studies. From a meta-analysis of 12 randomized controlled studies evaluating spironolactone's impact on HbA1c in diabetic patients, spironolactone had a nonsignificant effect in parallel-group studies (mean difference 0.03 [-0.20;0.26]), but significantly increased HbA1c in crossover studies (mean difference 0.24 [0.18;0.31]). Finally, eplerenone did not seem to influence glycemia, while limited data indicated that canrenone may exert a neutral or beneficial effect.The studies had important limitations regarding study design, sample size, duration of follow-up, and choice of glycemic markers.

CONCLUSION

Spironolactone may induce disease-specific and modest alterations on glycemia. It is uncertain whether these effects are transient or not. Data from the most extensively studied population, individuals with diabetes, do not support a long-term glycemic impact in these patients. Further prospective studies are necessary to establish spironolactone's true biological effects and their clinical implications.

Cross-sectional association between testosterone, sex hormone-binding globulin and metabolic syndrome: The Healthy Twin Study

OBJECTIVES

This study evaluated an association between testosterone, sex hormone-binding globulin (SHBG) and metabolic syndrome (MetS).We also evaluated the genetic and environmental influences on the association.

DESIGN

Cross-sectional.

SETTING

Community-based study.

PARTICIPANTS

A total of 1098 Korean adult men including 139 monozygotic twin pairs.

MAIN OUTCOME MEASURE

MetS was defined using the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP ATP III) and International Diabetes Federation (IDF) criteria. The associations between MetS and sex hormones were evaluated using linear mixed model and generalized estimating equation model.

RESULTS

After considering covariates such as smoking, alcohol consumption and physical exercises as well as SHBG or testosterone, the risk of MetS defined by NCEP ATP III criteria decreased by 31%, 29%, and 48%, respectively, with 1-standard deviation increase in total testosterone (TT), free testosterone (cFT) and SHBG. Similar findings were revealed with IDF criteria. Metabolic component specific analysis showed that sex hormones were inversely associated with several components of MetS: TT with abdominal obesity, low high-density lipoprotein cholesterol (HDL-C) and high blood pressure; cFT with abdominal obesity and high blood pressure; SHBG with all components except high blood pressure. Cotwin control analysis found an inverse correlation between within-pair differences in testosterone and SHBG levels and within-pair differences in waist circumference only.

CONCLUSION

Both testosterone and SHBG were inversely associated with MetS although the inverse associations with the sex hormones were not consistently found across individual metabolic components. Findings from cotwin analysis suggest a significant contribution of unshared unique environmental effect to the association between testosterone and SHBG and abdominal obesity.