Sex hormone-binding globulin, but not testosterone, is associated prospectively and independently with incident metabolic syndrome in men: the framingham heart study

The association between testosterone and serum soluble klotho in the females: evidence from the NHANES database

Objective

This research aimed to elucidate the relationship between testosterone levels and serum soluble klotho (S-klotho) concentrations in females aged 40-79 years using the National Health and Nutrition Examination Survey (NHANES) dataset.

Design

Associations between testosterone and S-klotho were assessed through multivariable linear regression methodologies, spanning nonadjusted, minimally adjusted, and fully adjusted models.

Settings

The investigation was conducted as a cross-sectional analysis utilizing the NHANES database.

Participants

From 20,146 NHANES participants between 2013 and 2016, 2,444 females met the stipulated inclusion and exclusion criteria.

Results

Free androgen index (FAI) showcased a negative correlation with S-klotho levels across all regression models (nonadjusted: β -7.08, 95% CI -13.39- -0.76; minimally adjusted: β -9.73, 95% CI -16.6- -2.84; fully adjusted: β -7.63, 95% CI -14.75-0.51). Conversely, total testosterone did not exhibit significant associations with S-klotho across the models. In the nonadjusted model, estradiol was positively associated with S-klotho concentrations (β 0.14, 95% CI 0.05-0.23), but this significance was not retained in subsequent regression models.

Conclusion

Findings suggest that in U.S. females aged 40-79 years, FAI negatively correlates with S-klotho concentrations, while there is the lack of significant associations for total testosterone and estradiol.

Higher testosterone and testosterone/estradiol ratio in men are associated with decreased Pheno-/GrimAge and DNA-methylation based PAI1

Sex hormones are hypothesized to drive sex-specific health disparities. Here, we study the association between sex steroid hormones and DNA methylation-based (DNAm) biomarkers of age and mortality risk including Pheno Age Acceleration (AA), Grim AA, and DNAm-based estimators of Plasminogen Activator Inhibitor 1 (PAI1), and leptin concentrations. We pooled data from three population-based cohorts, the Framingham Heart Study Offspring Cohort, the Baltimore Longitudinal Study of Aging, and the InCHIANTI Study, including 1,062 postmenopausal women without hormone therapy and 1,612 men of European descent. Sex-stratified analyses using a linear mixed regression were performed, with a Benjamini-Hochberg (BH) adjustment for multiple testing. Sex Hormone Binding Globulin (SHBG) was associated with a decrease in DNAm PAI1 among men (per 1 standard deviation (SD): -478 pg/mL; 95%CI: -614 to -343; P:1e-11; BH-P: 1e-10), and women (-434 pg/mL; 95%CI: -589 to -279; P:1e-7; BH-P:2e-6). The testosterone/estradiol (TE) ratio was associated with a decrease in Pheno AA (-0.41 years; 95%CI: -0.70 to -0.12; P:0.01; BH-P: 0.04), and DNAm PAI1 (-351 pg/mL; 95%CI: -486 to -217; P:4e-7; BH-P:3e-6) among men. In men, testosterone was associated with a decrease in DNAm PAI1 (-481 pg/mL; 95%CI: -613 to -349; P:2e-12; BH-P:6e-11). SHBG was associated with lower DNAm PAI1 among men and women. Higher testosterone and testosterone/estradiol ratio were associated with lower DNAm PAI and a younger epigenetic age in men. A decrease in DNAm PAI1 is associated with lower mortality and morbidity risk indicating a potential protective effect of testosterone on lifespan and conceivably cardiovascular health via DNAm PAI1.

Therapeutic applications of ginseng for skeletal muscle-related disorder management

Skeletal muscle (SM) is the largest organ of the body and is largely responsible for the metabolism required to maintain body functions. Furthermore, the maintenance of SM is dependent on the activation of muscle satellite (stem) cells (MSCs) and the subsequent proliferation and fusion of differentiating myoblasts into mature myofibers (myogenesis). Natural compounds are being used as therapeutic options to promote SM regeneration during aging, muscle atrophy, sarcopenia, cachexia, or obesity. In particular, ginseng-derived compounds have been utilized in these contexts, though ginsenoside Rg1 is mostly used for SM mass management. These compounds primarily function by activating the Akt/mTOR signaling pathway, upregulating myogenin and MyoD to induce muscle hypertrophy, downregulating atrophic factors (atrogin1, muscle ring-finger protein-1, myostatin, and mitochondrial reactive oxygen species production), and suppressing the expressions of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in cachexia. Ginsenoside compounds are also used for obesity management, and their anti-obesity effects are attributed to peroxisome proliferator activated receptor gamma (PPARγ) inhibition, AMPK activation, glucose transporter type 4 (GLUT4) translocation, and increased phosphorylations of insulin resistance (IR), insulin receptor substrate-1 (IRS-1), and Akt. This review was undertaken to provide an overview of the use of ginseng-related compounds for the management of SM-related disorders.

Higher testosterone and testosterone/estradiol ratio in men are associated with better epigenetic estimators of mortality risk

Introduction

Sex hormones are hypothesized to drive sex-specific health disparities. Here, we study the association between sex steroid hormones and DNA methylation-based (DNAm) biomarkers of age and mortality risk including Pheno Age Acceleration (AA), Grim AA, and DNAm-based estimators of Plasminogen Activator Inhibitor 1 (PAI1), and leptin concentrations.

Methods

We pooled data from three population-based cohorts, the Framingham Heart Study Offspring Cohort (FHS), the Baltimore Longitudinal Study of Aging (BLSA), and the InCHIANTI Study, including 1,062 postmenopausal women without hormone therapy and 1,612 men of European descent. Sex hormone concentrations were standardized with mean 0 and standard deviation of 1, for each study and sex separately. Sex-stratified analyses using a linear mixed regression were performed, with a Benjamini-Hochberg (BH) adjustment for multiple testing. Sensitivity analysis was performed excluding the previously used training-set for the development of Pheno and Grim age.

Results

Sex Hormone Binding Globulin (SHBG) is associated with a decrease in DNAm PAI1 among men (per 1 standard deviation (SD): -478 pg/mL; 95%CI: -614 to -343; P:1e-11; BH-P: 1e-10), and women (-434 pg/mL; 95%CI: -589 to -279; P:1e-7; BH-P:2e-6). The testosterone/estradiol (TE) ratio was associated with a decrease in Pheno AA (-0.41 years; 95%CI: -0.70 to -0.12; P:0.01; BH-P: 0.04), and DNAm PAI1 (-351 pg/mL; 95%CI: -486 to -217; P:4e-7; BH-P:3e-6) among men. In men, 1 SD increase in total testosterone was associated with a decrease in DNAm PAI1 (-481 pg/mL; 95%CI: -613 to -349; P:2e-12; BH-P:6e-11).

Conclusion

SHBG was associated with lower DNAm PAI1 among men and women. Higher testosterone and testosterone/estradiol ratio were associated with lower DNAm PAI and a younger epigenetic age in men. A decrease in DNAm PAI1 is associated with lower mortality and morbidity risk indicating a potential protective effect of testosterone on lifespan and conceivably cardiovascular health via DNAm PAI1.

Interaction between gut microbiota and sex hormones and their relation to sexual dimorphism in metabolic diseases

Metabolic diseases, such as obesity, metabolic syndrome (MetS) and type 2 diabetes (T2D), are now a widespread pandemic in the developed world. These pathologies show sex differences in their development and prevalence, and sex steroids, mainly estrogen and testosterone, are thought to play a prominent role in this sexual dimorphism. The influence of sex hormones on these pathologies is not only reflected in differences between men and women, but also between women themselves, depending on the hormonal changes associated with the menopause. The observed sex differences in gut microbiota composition have led to multiple studies highlighting the interaction between steroid hormones and the gut microbiota and its influence on metabolic diseases, ultimately pointing to a new therapy for these diseases based on the manipulation of the gut microbiota. This review aims to shed light on the role of sexual hormones in sex differences in the development and prevalence of metabolic diseases, focusing on obesity, MetS and T2D. We focus also the interaction between sex hormones and the gut microbiota, and in particular the role of microbiota in aspects such as gut barrier integrity, inflammatory status, and the gut-brain axis, given the relevance of these factors in the development of metabolic diseases.

Metal mixtures with longitudinal changes in lipid profiles: findings from the manganese-exposed workers healthy cohort

The majority of epidemiological investigations on metal exposures and lipid metabolism employed cross-sectional designs and focused on individual metal. We explored the associations between metal mixture exposures and longitudinal changes in lipid profiles and potential sexual heterogeneity. We recruited 250 men and 73 women, aged 40 years at baseline (2012), and followed them up in 2020, from the manganese-exposed workers healthy cohort. We detected metal concentrations of blood cells at baseline with inductively coupled plasma mass spectrometry. Lipid profiles were repeatedly measured over 8 years of follow-up. We performed sparse partial least squares (sPLS) model to evaluate multi-pollutant associations. Bayesian kernel machine regression was utilized for metal mixtures as well as evaluating their joint impacts on lipid changes. In sPLS models, a positive association was found between manganese and change in total cholesterol (TC) (beta = 0.169), while a negative association was observed between cobalt (beta =  - 0.134) and change in low density lipoprotein cholesterol (LDL-C) (beta =  - 0.178) among overall participants, which were consistent in men. Interestingly, rubidium was positively associated with change in LDL-C (beta = 0.273) in women, while copper was negatively associated with change in TC (beta =  - 0.359) and LDL-C (beta =  - 0.267). Magnesium was negatively associated with change in TC (beta =  - 0.327). We did not observe the significantly cumulative effect of metal mixtures on lipid changes. In comparison to other metals, manganese had a more significant influence on lipid change [group PIP (0.579) and conditional PIP (0.556) for TC change in men]. Furthermore, male rats exposed to manganese (20 mg/kg) had higher levels of LDL-C in plasma and more apparent inflammatory infiltration, vacuolation of liver cells, nuclear pyknosis, and fatty change than the controls. These findings highlight the potential role of metal mixtures in lipid metabolism with sex-dependent heterogeneity. More researches are needed to explore the underlying mechanisms.

Correlates of testosterone change as men age

Objective: The literature on testosterone (T) in men reports diverse correlates of T, some with minimal empirical support and most with little indication of how they change with advancing age. We test eight putative correlations across age.Method: Correlations were tested on a large sample of British men.Results: Seven of eight correlations replicated. Most change across men's life courses. The diurnal cycle of T is considerably weaker among older than younger men. Single men have higher T than married men of the same age; however, this difference lessens as men get older. Elevated T among smokers is less pronounced as men age. The inverse relationship between obesity and T is sustained across the adult age range. The lessening of T with age is well established, however there is disagreement about the course of decline. We find T having a steep decline around age 30, with possibly a rebound around age 50, after which levels remain roughly constant. Correlations involving health become stronger among older men. After age 30 or 40, the inverse relationships between T and HbA1c, diabetes, and metabolic syndrome all become increasingly significant, though not necessarily strong in magnitude.Conclusion: Most putative correlates of T are replicated. There is a basis here for the generalization that among older men, those healthy have higher T than those who are not, but not a lot higher.

Sex hormones and the risk of cardiovascular disease and mortality in male and female patients with chronic kidney disease: A systematic review and meta-analysis

Patients with chronic kidney disease (CKD) commonly experience sex hormone disturbances, which may be associated with the risk of cardiovascular disease (CVD) and mortality. This review aimed to systematically evaluate current findings on the association of sex hormone levels with the risk of CVD events and mortality (CVD and all-cause) in the CKD population. Articles were systematically searched in CINAHL, Cochrane, and PubMed. A total of 1739 articles were independently screened by two reviewers and 17 prospective cohort studies were included. The clinical conditions of the patients were those with non-dialysis CKD [mean/median estimated glomerular filtration rate (eGFR) between 15-51 ml/min/1.73 m2 ] and those on chronic dialysis (mean/median vintage between 6-125 months). The sample size ranged from 111 to 2419 and the mean/median age of subjects ranged from 52 to 72 years. The sex hormones studied were testosterone, estradiol, prolactin, dehydroepiandrosterone sulfate, and relaxin. A random-effects model was used to generate a pooled hazard ratio (HR) to evaluate the association of total testosterone levels with the risk of CVD and all-cause mortality. Most studies examined total testosterone levels (11 out of 17 studies) and studied only male patients (12 out of 17 studies). A lower total testosterone level was associated with a higher risk of CVD mortality [HR 4.37 (95% CI 1.40-13.65)] and all-cause mortality [1.96 (1.35-2.83)] in males with CKD. To conclude, there is a strong need for additional studies examining the association of sex hormones with cardiovascular and mortality risk in female patients with CKD.

Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders

The circulating concentrations of total and free testosterone vary substantially in people over time due to biologic factors as well as due to measurement variation. Accurate measurement of total and free testosterone is essential for making the diagnosis of androgen disorders. Total testosterone should ideally be measured in a fasting state in the morning using a reliable assay, such as liquid chromatography tandem mass spectrometry, in a laboratory that is certified by an accuracy-based benchmark. Free testosterone levels should be measured in men in whom alterations in binding protein concentrations are suspected or in whom total testosterone levels are only slightly above or slightly below the lower limit of the normal male range for testosterone.

Total Testosterone to Estradiol Ratio as a Predictor Marker of Metabolic Syndrome in Males

Nowadays, metabolic syndrome (MetS) represents a global health challenge in developed and developing countries. The sex hormones disorders in males are related to many clinical co-morbidities. This study aimed to evaluate the total testosterone (TT) to estradiol (E2) ratio as a predictor marker of MetS. This case-control study included 88 MetS patients and 88 healthy individuals (control), in the age range of 18-69 years who were selected among patients who were referring to an outpatient clinic, using a convenience sampling method. The study participants were selected based on their medical history and physical examination, which included waist circumference, blood pressure, serum E2, TT, fasting blood glucose (FBG), triglyceride (TG), and high-density lipoprotein-cholesterol (HDL-C). Diagnosis of MetS was confirmed according to the National Cholesterol Education Program Adult Treatment Panel III guidelines. The findings revealed that the mean TT level was significantly lower among patients with MetS (P<0.001), while the mean E2 level was significantly higher among patients with MetS (P<0.001). The mean TT to E2 ratio was significantly lower among patients with MetS (OR=9.6, P<0.001). There was a significant correlation between MetS components and TT to E2 ratio and waist circumference (WC) (r = - 0.49, P<0.0001). The means of weight, WC, blood pressure, and FBG levels were significantly higher in patients with MetS (P<0.001, P<0.001, P<0.001, P=0.04, respectively), and the lipid profile of patients with MetS was abnormal (TG, P<0.001, HDL-C, P<0.001). Eventually, it can be concluded that the TT to E2 ratio can be regarded as a significant predictor of MetS in males.

Longitudinal Changes in Sex Hormone-Binding Globulin in Men With HIV

BACKGROUND

Sex hormone-binding globulin (SHBG) is a glycoprotein that regulates sex hormone bioavailability and increases with age in the general population. SHBG concentrations are higher in people with HIV, a population in whom accelerated aging has been hypothesized. It is unclear whether longitudinal changes in SHBG increase over time and differ by HIV serostatus.

METHODS

In a longitudinal study, SHBG was measured in 182 men with HIV (MWH) and 267 men without HIV (seronegative) from the Multicenter AIDS Cohort Study and matched for age, race, site, and time, with ≥2 SHBG serum samples over the 10 years after HAART initiation. Multivariable linear mixed-effects regression models were used to evaluate whether log-transformed SHBG [ln(SHBG)] and its rate of change differed by HIV serostatus.

RESULTS

At baseline, the mean age in MWH was similar to that in HIV-seronegative men (51 ± 5 vs 49 ± 6 years). However, SHBG mean values were higher in MWH compared with those in HIV-seronegative men (65.6 ± 48.8 vs. 45.4 ± 22 nmol/L, P < 0.001). In a fully adjusted model, SHBG increased over time and at a faster rate in MWH compared with that in HIV-seronegative men: [2.0%/year (95% CI: 1.4 to 2.7) vs 1.3%/year (95% CI: 0.8 to 1.8), respectively, P = 0.038]. Among MWH, higher SHBG concentrations were significantly associated with lower CD4+ T-cell count [β= -0.02 (95% CI: -0.03 to -0.0002), P < 0.05], fewer cumulative years on zidovudine [β = -0.027 (95% CI: -0.045 to -0.009), P < 0.001], and greater cumulative years on nonnucleoside reverse transcriptase inhibitors drugs [β = 0.022 (95% CI: 0.0006 to 0.04), P < 0.05].

CONCLUSIONS

Aging-related increases in SHBG were faster in MWH compared with those in HIV-seronegative men and were related to poorer immunologic status and antiretroviral medication exposure. The mechanisms and consequences of these findings require further investigation.

Anabolic-Androgenic Steroid Use in Sports, Health, and Society

This consensus statement is an update of the 1987 American College of Sports Medicine (ACSM) position stand on the use of anabolic-androgenic steroids (AAS). Substantial data have been collected since the previous position stand, and AAS use patterns have changed significantly. The ACSM acknowledges that lawful and ethical therapeutic use of AAS is now an accepted mainstream treatment for several clinical disorders; however, there is increased recognition that AAS are commonly used illicitly to enhance performance and appearance in several segments of the population, including competitive athletes. The illicit use of AAS by competitive athletes is contrary to the rules and ethics of many sport governing bodies. Thus, the ACSM deplores the illicit use of AAS for athletic and recreational purposes. This consensus statement provides a brief history of AAS use, an update on the science of how we now understand AAS to be working metabolically/biochemically, potential side effects, the prevalence of use among athletes, and the use of AAS in clinical scenarios.

Association of Metabolic Obesity Phenotypes and Total Testosterone in Chinese Male Population

OBJECTIVE

Obesity and metabolic syndrome have been reported to exert an impact on the male reproductive system with decreasing levels of serum total testosterone (TT); however, the effect of different metabolic obesity phenotypes on testosterone has been poorly studied. We aimed to evaluate the association of metabolic obesity phenotypes and total testosterone levels in a Chinese male population.

METHODS

We performed a retrospective study based on an epidemiological investigation, a total of 4,081 male individuals aged from 40-75 years old were recruited. The population was classified as metabolically healthy normal weight (MHNW), metabolically healthy overweight/obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight/obese (MUO) according to normal weight (BMI<25.0) and overweight/obesity (BMI≥25.0) with or without metabolic syndrome.

RESULTS

We collected 563 hypotestosteronemia among 4,081 male individuals. The odds ratios (ORs) (95% CIs) of hypotestosteronemia in obesity and metabolic syndrome were 3.072 (2.414-3.911) and 3.294 (2.631-4.125), respectively, after adjusting for age, luteinizing hormone, smoking status, and alcohol consumption. Compared to the MHNW group, male subjects in MHO, MUNW, and MUO groups had decreased serum TT levels. Additionally, the MUO group had a lowest concentration of serum TT and a highest proportion of hypotestosteronemia. There was no significant difference of TT levels between the MHO and MUNW groups.

CONCLUSION

Obesity and metabolic syndrome are independent risk factors of hypotestosteronemia in Chinese male populations. Our study also suggested that individuals with MHO, MUNW, and MUO have a higher risk of developing hypotestosteronemia.

Benefits and Risks of Testosterone Treatment in Men with Age-Related Decline in Testosterone

The substantial increase in life expectancy of men has focused growing attention on quality-of-life issues associated with reproductive aging. Serum total and free testosterone levels in men, after reaching a peak in the second and third decade of life, decline gradually with advancing age. The trajectory of age-related decline is affected by comorbid conditions, adiposity, medications, and genetic factors. Testosterone treatment of older men with low testosterone levels improves overall sexual activity, sexual desire, and erectile function; improves areal and volumetric bone density, as well as estimated bone strength in the spine and the hip; corrects unexplained anemia of aging; increases skeletal muscle mass, strength and power, self-reported mobility, and some measures of physical function; and modestly improves depressive symptoms. The long-term effects of testosterone on major cardiovascular events and prostate cancer risk remain unclear. The Endocrine Society recommends against testosterone therapy of all older men with low testosterone levels but suggests consideration of treatment on an individualized basis in men who have consistently low testosterone levels and symptoms or conditions suggestive of testosterone deficiency.

The effect of Korean Red Ginseng on sarcopenia biomarkers in type 2 diabetes patients

BACKGROUND

The elderly population is growing rapidly worldwide and sarcopenia, which is considered as a new geriatric syndrome has become an important issue. In particular, diabetes is known to be an important risk factor for sarcopenia. In this study, we investigated the effects of Korean Red Ginseng (KRG) on biomarkers of sarcopenia in middle and old age diabetes patients.

PATIENTS AND METHODS

This study was a randomized, double-blind, placebo-controlled trial. Participants were randomly allocated to either the placebo or KRG group and took corresponding tablets for 24 weeks. The primary outcomes were changes in sarcopenia biomarkers at week 24. Secondary outcomes were changes in inflammatory and antioxidant markers and lean body mass at week 24.

RESULTS

Fifty-nine patients completed the study. Follistatin and sex hormone binding globulin (SHBG) were significantly improved in KRG group. In the subgroup analysis, female postmenopausal patients over the age of 55 showed a significant improvement in serum SHBG, follistatin, and growth differentiation factor 15 (GDF-15) and an attenuated reduction in Troponin T (TNT) after the administration of KRG.

CONCLUSION

Twenty-four week administration of KRG in diabetes patients resulted in a significant improvement in follistatin and SHBG levels, especially in old postmenopausal women. A further, larger population study with a longer follow-up period is warranted to verify and understand the effects of KRG on sarcopenia.

Longitudinal associations between sex hormone-binding globulin and insulin resistance

PURPOSE

We aimed to investigate the association between SHBG and the homeostatic model assessment of insulin resistance (HOMA-Ir) in men and women in a prospective observational study.

METHODS

The Vara-Skövde cohort is a random population of 2816 participants living in southwestern Sweden, aged 30-74. It was recruited between 2002 and 2005, and followed up in 2012-2014. After excluding participants on insulin therapy or hormone replacement therapy, 1193 individuals (649 men, 544 women) were included in the present study. Fasting blood samples were collected at both visits and stored in biobank. All participants were physically examined by a trained nurse. SHBG was measured with immunoassay technique. Linear regressions were computed to investigate the association between SHBG and HOMA-Ir both in cross-sectional and longitudinal analyses, adjusting for confounding factors.

RESULTS

The mean follow-up time was 9.7 ± 1.4 years. Concentrations of SHBG were significantly inversely associated with log transformed HOMA-Ir in all groups with estimated standardized slopes (95% CI): men: -0.20 (-0.3;-0.1), premenopausal women: -0.26 (-0.4;-0.2), postmenopausal women: -0.13 (-0.3;-0.0) at visit 1. At visit 2 the results were similar. When comparing the groups, a statistically significant difference was found between men and post-menopausal women (0.12 (0.0;0.2) P value = 0.04). In the fully adjusted model, SHBG at visit 1 was also associated with HOMA-Ir at visit 2, and the estimated slopes were -0.16 (-0.2;-0.1), -0.16 (-0.3;-0.1) and -0.07 (-0.2;0.0) for men, premenopausal and postmenopausal women, respectively.

MAIN CONCLUSION

Levels of SHBG predicted the development of insulin resistance in both men and women, regardless of menopausal state.

The underlying mechanism of metabolic syndrome on benign prostatic hyperplasia and prostate volume

OBJECTIVE

To investigate the potential mechanism of the effect of metabolic syndrome (MetS) on prostate volume (PV) and the risk of benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS) and the relationships of MetS and the major pathogenic factors of MetS with the clinical progression of BPH/LUTS in older Chinese men.

SUBJECTS AND METHODS

We analyzed clinical data obtained from 506 ostensibly healthy men who underwent routine health check-ups and recruited 415 subjects from a group of previously studied men after 4 years. We evaluated the associations of major pathological factors of MetS, including insulin resistance, subclinical inflammatory state, and sex hormone changes, with PV, the risk of BPH and the clinical progression of BPH/LUTS by using multiple linear regression and logistic regression.

RESULTS

After adjustment for age, insulin, HOMA (homeostatic model assessment) index, leptin, resistin, adiponectin, C-reactive protein, tumor necrosis factor-α (TNF-α), sex hormone-binding globulin, and testosterone levels were significantly associated with PV (all P < .05), and in the age-adjusted logistic regression model, positive associations of resistin and TNF-α with BPH/LUTS were found (OR, 1.662, P = .007 and OR, 1.044, P < .001, respectively). Predictors of BPH/LUTS clinical progression were significantly correlated with MetS and TNF-α. The group with higher TNF-α levels had a higher rate of newly diagnosed BPH (9.5% vs 19.1%, P = .006) and a greater increase in PV levels (0.61 ± 0.08 vs 1.09 ± 0.35 cm³ , P <.001) after 4 years.

CONCLUSIONS

MetS and its pathological factors were associated with an increased PV and an increased risk of BPH/LUTS that is more prone to clinical progression. TNF-α may serve as an early biological indicator to identify which patients with BPH/LUTS are at higher risk of unfavorable outcomes.

Serum SHBG Is Associated With the Development and Regression of Nonalcoholic Fatty Liver Disease: A Prospective Study

CONTEXT

SHBG, a homodimeric glycoprotein produced by hepatocytes has been shown to be associated with metabolic disorders. Whether circulating SHBG levels are predictive of later risk of nonalcoholic fatty liver disease (NAFLD) remains unknown. In this study, we prospectively investigated the association between SHBG and NAFLD progression through a community-based cohort comprising 3389 Chinese adults.

METHODS

NAFLD was diagnosed using abdominal ultrasonography. Serum SHBG levels were measured by chemiluminescent enzyme immunometric assay, and their relationship with NAFLD development and regression was investigated after a mean follow-up of 3.09 years using multivariable logistic regression.

RESULTS

Basal SHBG was negatively associated with NAFLD development, with a fully adjusted odds ratio (OR) and its 95% confidence interval (CI) of 0.22 (0.12-0.40) (P < .001). In contrast, basal SHBG was positively associated with NAFLD regression, with a fully adjusted OR of 4.83 (2.38-9.81) (P < .001). Multiple-stepwise logistic regression analysis showed that SHBG concentration was an independent predictor of NAFLD development (OR, 0.28 [0.18-0.45]; P < .001) and regression (OR, 3.89 [2.43-6.22]; P < .001). In addition, the area under the receiver operating characteristic curves were 0.764 (95% CI, 0.740-0.787) and 0.762 (95% CI, 0.738-0.785) for the prediction models of NAFLD development and regression, respectively.

CONCLUSIONS

Serum SHBG concentration is associated with the development and regression of NAFLD; moreover, it can be a potential biomarker for predicting NAFLD progression, and also a novel preventive and therapeutic target for NAFLD.

Prognostic value of testosterone for the castration-resistant prostate cancer patients: a systematic review and meta-analysis

INTRODUCTION

This systematic review and meta-analysis aimed to assess the prognostic value of testosterone in patients with castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

PubMed, Web of Science, and Scopus databases were systematically searched until December 2019, according to the Preferred Reporting Items for Systemic Review and Meta-analysis statement. The endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

We identified 11 articles with 4206 patients for systematic review and nine articles with 4136 patients for meta-analysis. Higher testosterone levels were significantly associated with better OS (pooled HR 0.74, 95% CI 0.58-0.95) and better PFS (pooled HR 0.51, 95% CI 0.30-0.87). Subgroup analyses based on the treatment type revealed that higher testosterone levels were significantly associated with better OS in CRPC patients treated with androgen receptor-targeted agents (ARTAs) (pooled HR 0.64, 95% CI 0.55-0.75), but not in those treated with chemotherapy (pooled HR 0.78, 95% CI 0.53-1.14).

CONCLUSION

This meta-analysis demonstrated that the PFS and OS were significantly greater in patients with CRPC in those with higher testosterone levels than that of those with lower testosterone levels. In the subgroup analyses, lower testosterone levels were a consistently poor prognostic factor for OS in patients treated with ARTAs, but not in those treated with chemotherapy. Therefore, higher testosterone levels could be a useful biomarker to identify patient subgroups in which ARTAs should be preferentially recommended in the CRPC setting.

The association of pathogenic factors of metabolic syndrome on serum prostate-specific antigen levels: a pilot study

Background

Metabolic syndrome (MetS) and serum prostate-specific antigen (PSA) levels are correlated. To investigate the underlying effect of MetS on PSA levels, the relationship between the major pathogenic factors of MetS and serum PSA levels was studied.

Methods

A total of 506 ostensibly healthy men who underwent routine health check-ups were recruited to this study. We evaluated the effect of the major pathogenic factors of MetS, which included insulin resistance, a subclinical inflammatory state and sexual hormone changes, on serum PSA levels by using linear regression analysis and multivariate analysis after adjusting for age, BMI and prostate volume.

Results

When simultaneously adjusting for age, BMI, prostate volume and high-density lipoprotein cholesterol, serum insulin levels and SHBG levels were inversely correlated with serum PSA levels (P = 0.049 and P = 0.004, respectively), and testosterone levels were positively correlated with serum PSA levels (P = 0.039). In multivariate regression models, serum insulin levels and serum SHBG levels were significantly associated with serum PSA levels (both P < 0.001).

Conclusions

Among the major pathogenic factors of metabolic syndrome, insulin resistance and sexual hormone changes may be the most significant contributors to the decline in serum PSA levels.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

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.

Sex Hormone-Binding Globulin Levels in Young Men Are Associated With Nonalcoholic Fatty Liver Disease in Midlife

INTRODUCTION

Cross-sectional data note lower levels of testosterone and sex hormone-binding globulin (SHBG) levels in men with nonalcoholic fatty liver disease (NAFLD). Whether sex hormone levels in young men are predictive of later risk of NAFLD is not known.

METHODS

Among men in the prospective population-based multicenter Coronary Artery Risk Development in Young Adults study (mean age 50; n = 837), we assessed whether testosterone and SHBG levels measured at study year 10 (median age 35 years) were associated with prevalent NAFLD at study year 25. NAFLD was defined using noncontrast abdominal computed tomography (CT) scan after excluding other causes of hepatic steatosis. The association of testosterone and SHBG with prevalent NAFLD was assessed by logistic regression.

RESULTS

Total testosterone levels in young men were inversely associated with subsequent prevalent NAFLD on unadjusted analysis (odds ratio [OR] 0.64, 95% confidence interval 0.53-0.7, P < 0.001), although no longer significant after adjustment for year 10 metabolic covariates as well as change in metabolic covariates from years 10 to 25 (OR 0.99, 95% confidence interval 0.76-1.27). In contrast, there was a significant inverse association of SHBG with prevalent NAFLD, independent of testosterone and metabolic covariates (OR 0.68, OR 0.51-0.92, P = 0.013). On formal mediation testing, visceral adiposity was found to explain ∼41.0% (95% confidence interval 27%-73%) of the association of lower SHBG with prevalent NAFLD.

CONCLUSIONS

Lower levels of SHBG in young men are associated with increase in prevalent NAFLD in middle age, independent of comprehensive metabolic risk factors. SHBG may provide a novel marker of NAFLD risk in young men.

Endogenous circulating testosterone and sex hormone-binding globulin levels and measures of myocardial structure and function: the Framingham Heart Study

BACKGROUND

The relation between endogenous testosterone concentrations and myocardial mass and function remains incompletely understood.

OBJECTIVES

To determine the cross-sectional association between endogenous hormone levels with cardiac magnetic resonance measures of myocardial mass, structure, and function in community-dwelling men across a wide age range.

METHODS

A total of 720 men from the Framingham Heart Study Offspring Cohort (age range 37-82, mean = 59.6 years) who underwent cardiac magnetic resonance imaging and had hormone levels measured. Total testosterone (measured using liquid chromatography-tandem mass spectrometry), sex hormone-binding globulin (measured using an immunofluorometric assay), and calculated free testosterone levels were assessed in male participants of the Framingham Heart Study Offspring Cohort at examination 7. Cardiac magnetic resonance imaging was performed between examinations 7 and 8 (2002-2006).

RESULTS

Age-adjusted linear regression models showed statistically significant association between total testosterone levels and left ventricular mass (p = 0.009), left ventricular mass index (p = 0.006), cardiac output (p = 0.001), and main pulmonary artery diameter (p = 0.008); the association between total testosterone and these cardiac magnetic resonance measures was weak and was not significant after adjustment for established risk factors-age, body mass index, diabetes, and hypertension. Furthermore, calculated free testosterone level was not significantly associated with any measure of myocardial mass or function. Sex hormone-binding globulin level was significantly associated with left ventricular mass (p = 0.002), left ventricular mass index (p = 0.004), cardiac output (p = 0.003), left ventricular ejection fraction (p = 0.039), and main pulmonary artery diameter (p = 0.042) in age-adjusted models; these associations were also rendered non-significant after adjusting for cardiovascular risk factors.

CONCLUSIONS

Neither testosterone nor sex hormone-binding globulin levels in men are associated significantly with myocardial mass and function independent of established cardiovascular risk factors.

Serum testosterone, sex hormone-binding globulin and sex-specific risk of incident type 2 diabetes in a retrospective primary care cohort

OBJECTIVE

Previous studies suggest that androgens have a sexually dimorphic impact on metabolic dysfunction. However, the sex-specific link between circulating androgens and risk of type 2 diabetes mellitus (T2DM) has not been examined in a large scale, longitudinal cohort, a task we undertook in this study.

DESIGN

A retrospective cohort study in a UK primary care database.

PATIENTS

We included men and women with available serum testosterone and sex hormone-binding globulin (SHBG) results.

MEASUREMENTS

We categorized serum concentrations according to clinically relevant cut-off points and calculated crude and adjusted T2DM Incidence Rate Ratios (IRRs and aIRRs).

RESULTS

Serum testosterone concentrations were available in 70 541 men and 81 889 women; serum SHBG was available in 15 907 men and 42 034 women. In comparison to a reference cohort with serum testosterone ≥20 nmol/L, men with lower serum testosterone had a significantly increased risk of T2DM, with the highest risk in those with serum testosterone <7 nmol/L (aIRR 2.71, 95% CI 2.34-3.14, P < 0.001). In women, the risk of T2DM started to increase significantly when serum testosterone concentrations exceeded 1.5 nmol/L, with the highest risk in women with serum testosterone ≥3.5 nmol/L (aIRR 1.98, 95% CI 1.55-2.52, P < 0.001). These observations were verified in a continuous rather than categorized analysis. The risk of T2DM increased in men and women with serum SHBG <40 and <50 nmol/L, respectively.

CONCLUSIONS/INTERPRETATION

In this longitudinal study, we found sexually dimorphic associations between serum testosterone and risk of incident T2DM. Androgen deficiency and excess should be considered important risk factors for diabetes in men and women, respectively.

Can Low SHBG Serum Concentration Be A Good Early Marker Of Male Hypogonadism In Metabolic Syndrome?

INTRODUCTION

In men suffering from metabolic syndrome, accompanying insulin resistance may result in a lowering of sex hormone-binding globulin (SHBG) plasma levels and cause changes in their androgenic status.

AIM

The objective of the research was to assess selected androgens and SHBG plasma levels in males meeting diagnostic criteria for MS compared to healthy males.

PATIENTS AND METHODS

The group consisted of 65 men aged between 40 and 70 years old fitting IDF metabolic syndrome criteria and 84 controls. Dehydroepiandrosterone (DHEA) and its sulphate (DHEA-S), total and free testosterone and SHBG serum levels were evaluated. Calculated free and bioavailable testosterone were estimated using an algorithm proposed by the International Society for the Study of the Aging Male.

RESULTS

Men diagnosed with MS showed a statistically significant decrease in plasma levels of DHEA in comparison to healthy ones: 11.579 (8.39-15.56) vs 14.014 (9.611-17.125) ng/mL; p = 0.0350, SHBG: 47.46 (35.78-62.83) vs 71.965 (54.45-91.56) nM/L; p<0.0001 and total testosterone: 5.2 (3.8-6.5) vs 6.3 (5.4-8.25) ng/mL; p = 0.0001 (values presented as a median with Q1-Q3).

CONCLUSION

The results suggest that SHBG is a good early marker for metabolic dysregulation in MS, considering its strength of association and significance is comparable to, or better than, those of MS criteria.

Inverse association of testosterone and sex hormone binding globulin levels with leukocyte count in middle-aged and elderly men

OBJECTIVE

The inverse associations of testosterone and sex hormone-binding globulin (SHBG) levels with cardiometabolic diseases are well established and are increasingly viewed as inflammatory diseases. This study aimed to examine the associations of testosterone and SHBG levels with leukocyte count in 451 Korean men aged ≥50 years.

METHODS

Serum testosterone and SHBG levels were categorized into tertiles. High leukocyte count was defined as ≥7340 cells/μl, which corresponded to the 75th percentile of the current sample. The odds ratios (ORs) and 95% confidence intervals (95% CIs) for high leukocyte count were calculated across testosterone and SHBG tertiles using multiple logistic regression analysis.

RESULTS

The mean leukocyte counts significantly decreased with increasing testosterone and SHBG tertiles. The ORs (95% CIs) of high leukocyte count for the first tertile of testosterone and SHBG were 3.27 (1.34-7.95) and 2.38 (1.05-5.96), respectively, compared with the referent third tertile, after adjusting for age, smoking status, alcohol drinking, regular exercise, body mass index, blood pressure, fasting plasma glucose, triglyceride, and high-density lipoprotein (HDL) cholesterol level.

CONCLUSION

We found inversely graded associations of low testosterone and SHBG levels with leukocyte count. These findings suggest that low testosterone and SHBG levels may be interpreted as a state of low-grade inflammation.

Association of central obesity with sex hormonebinding globulin: a cross-sectional study of 1166 Chinese men

Background Both sex hormone-binding globulin and central obesity have been found to be associated with metabolic and cardiovascular diseases. However, the direct relation between sex hormone-binding globulin and central obesity has not been demonstrated.

Methodology We performed a cross-sectional study of 1166 male participants from Zunyi, Guizhou, western China, in 2013. Each participant completed a questionnaire and had a brief clinical exam with a fasting blood sample taken. All blood samples underwent standard laboratory testing for sex hormone-binding globulin. Level of serum sex hormone-binding globulin was compared by demographic characteristics, and multiple linear regression was used to evaluate the independent association of variables and sex hormone-binding globulin level.

Results The mean serum level of sex hormone-binding globulin was increased in old-aged men (older than 40 years; mean 44.68±20.58 nmol/L), low diastolic blood pressure (<90mmHg; 43.76±20.50 nmol/L), waist-to-height ratio <0.5 (48.73±20.59 nmol/L), no education (52.36±22.91 nmol/L), farm occupation (43.58±20.60nmol/L), non-alcohol or former user (44.78±20.94 nmol/L) and long-term medication history (44.79±21.50 nmol/L). Factors independently associated with sex hormone binding globulin level on multiple regression were waist-to-height ratio (β=- 11.84 [95% confidence interval -13.96,-9.72]), age(β=12.40 [9.63,15.17]) and diastolic blood pressure (β=-5.07 [-7.44,-2.71]).

Conclusions Central obesity has an independent inverse relation with serum level of sex hormone binding globulin among western Chinese men

Testosterone, frailty and physical function in older men

INTRODUCTION

Age-related decline in serum testosterone (T) has been suggested in some studies to be associated with individual components of frailty: diminished energy, muscle strength and physical function.

AREAS COVERED

The aim of this study is to comprehensively review evidence from observational and interventional studies on the relationship of T to frailty in older men. We reviewed observational studies exploring the relationship between circulating T and its potent metabolite dihydrotestosterone (DHT) with frailty. We further reviewed the effects of T treatment on lean mass, muscle strength and physical function in both frail and non-frail older men.

EXPERT COMMENTARY

T treatment may provide modest improvements in lean mass among both frail and non-frail older men, but current evidence on the T effect on muscle strength is conflicting and the effect on physical function is weak.

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.

Impact of Metabolic Syndrome Factors on Testosterone and SHBG in Type 2 Diabetes Mellitus and Metabolic Syndrome

OBJECTIVE

Several studies have often reported low testosterone and SHBG to be associated with type 2 DM and the metabolic syndrome (MetS). Our objective was to determine the impact of metabolic syndrome and diabetic parameters on testosterone and SHBG in both MetS subjects and type 2 DM patients.

METHODS

In this study, 120 Yemeni male aged 30-70 years old were enrolled, 30 of whom were healthy subjects with BMI < 25 kg/m² that served as control, 30 MetS, 30 type 2 DM without MetS, and 30 type 2 DM with MetS according to IDF criteria.

RESULTS

Testosterone (free and total) and SHBG were significantly lower in MetS subjects and modestly reduced in type 2 DM with and without MetS. Stepwise linear regression showed free and total testosterone to be negatively affected by waist circumference, and univariate analysis shows this significant difference to disappear when adjusted for waist circumference. On the other hand, stepwise linear regression showed SHBG to be positively affected by testosterone and age and negatively affected by FBG and TG. Univariate analysis shows this observed significant difference to disappear when adjusted for testosterone.

CONCLUSION

Abdominal obesity is a major determinant of low testosterone levels irrespective of diabetes status. Thus, supporting evidence suggesting that the causative relationship between the often low testosterone and type 2 DM might be bidirectional or even multidirectional and interrelated with obesity, MetS, and IR.

Non-alcoholic fatty liver disease is an influencing factor for the association of SHBG with metabolic syndrome in diabetes patients

Metabolic syndrome (MS) and non-alcoholic fatty liver disease (NAFLD) have been identified as risk factors affecting serum sex hormone binding globulin (SHBG) levels. We conducted this cross-sectional study to delineate whether MS or NAFLD has more impact on circulating SHBG levels in type 2 diabetes (T2D) patients. Anthropometric and biochemical parameters including serums SHBG, testosterone (TT), liver enzymes, lipids, insulin, C-peptide and plasma glucose were measured. Regardless of the MS status, SHBG level was significantly lower in NAFLD patients than in non-NAFLD patients (P < 0.001). In the multiple linear regression analysis, lower serum SHBG level was strongly correlated with a higher incidence of NAFLD, but not MS components. In logistic regression analyses, after adjusted for age, sex, duration of diabetes, smoking status, and alcohol use, the ORs and 95%CI for presence of MS was 2.26 (95%CI 1.91–2.68) and for presence of NAFLD was 6.36 (95%CI 4.87–8.31) with per one SD decrease in serum SHBG (both P < 0.001). In conclusion, lower serum SHBG is associated with a higher prevalence of NAFLD, compared with MS and other metabolic disorders, in T2D patients. NAFLD might be an important influencing factor for the association of circulating SHBG with MS in T2D patients.

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.

Sex hormones and brain volumes in a longitudinal study of middle-aged men in the CARDIA study

INTRODUCTION

Several findings suggest that testosterone (T) is neuroprotective and that declining T levels during aging are associated with cognitive and brain pathologies; however, little is known on T and brain health in middle-age. We examined the relationships of total T, bioavailable T, and sex hormone binding globulin (SHBG) levels with total and regional gray matter (GM) and white matter (WM) volumes in middle-aged men. We also evaluated the association of sex hormone levels with cognitive function.

METHODS

Analysis included 267 community-dwelling men participating in the Coronary Artery Risk Development in Young Adults (CARDIA) brain magnetic resonance imaging (MRI) substudy. Total T, bioavailable T, and SHBG levels were measured at three times from the 2nd to 4th decade of life; brain volumes were measured at the ages of 42-56. Associations were estimated using linear regression models, adjusted for several potential confounders.

RESULTS

Higher SHBG levels were associated with greater total WM volume (+3.15 cm3 [95% confidence interval [CI] = 0.01, 6.28] per one standard deviation higher SHBG). Higher SHBG levels were associated with lower total and regional GM volumes overall and significantly with smaller parietal GM volume (-0.96 cm3 [95%CI = -1.71, -0.21]). T levels were not related to brain volumes. Neither T nor SHBG levels were associated with cognitive function.

CONCLUSION

Results suggest a role for SHBG in structural brain outcomes in men and emphasize the value of investigating SHBG levels as modulators of sex hormone and metabolic pathways regulating brain and behavioral characteristics in men.

Resveratrol Increases Hepatic SHBG Expression through Human Constitutive Androstane Receptor: a new Contribution to the French Paradox

Sex hormone-binding globulin (SHBG) carries sex steroids in blood regulating their bioavailability. Red wine consumption increases plasma SHBG levels, and we have discovered that resveratrol, a polyphenol enriched in red wine, acts specifically through the human constitutive androstane receptor (CAR), a drug/xenobiotic detoxification gene regulator, to increase hepatic SHBG production. Chromatin immunoprecipitation and luciferase reporter gene assays show that human CAR binds to a typical direct repeat 1 nuclear hormone receptor-binding element in the human SHBG proximal promoter. Resveratrol also increased hepatic SHBG production in humanized SHBG/CAR transgenic mice. Moreover, SHBG expression correlated significantly with CAR mRNA levels in human liver biopsies. We conclude that the beneficial effects of red wine on the metabolic syndrome and it associated co-morbidities, including cardiovascular disease and type 2 diabetes, may be mediated in part by resveratrol acting via CAR to increase plasma SHBG levels.

Predictive Value of Serum Gamma-glutamyltranspeptidase for Future Cardiometabolic Dysregulation in Adolescents- a 10-year longitudinal study

Serum gamma-glutamyltransferase (γ-GT) is implicated in the pathogenesis of atherosclerosis and metabolic syndrome (MetS) in adults. The relationships between γ-GT and cardiometabolic dysregulation remains unclear in adolescents. We enrolled 7,072 Taiwanese adolescents and followed them for a median of 6.8 years. The optimal cut-off values (CoVs) of baseline γ-GT to predict future MetS, hypertension (HTN), and type 2 diabetes (T2DM) were determined by receiving operating characteristic (ROC) curve. Using these CoVs, the participants were divided into normal- and high-level groups. Cox proportional hazard analysis was used to calculate hazard ratios (HRs) for the subjects with a high level of γ-GT for the risk of future cardiometabolic dysregulation. Serum γ-GT was significantly higher in the subjects with MetS than in those without MetS at baseline (p < 0.001). The optimal CoVs of γ-GT were 12 U/L for boys and 11 U/L for girls. In multivariate Cox regression analysis, a higher serum γ-GT level increased the risk of future MetS (HRs 1.98 and 2.85 for boys and girls, respectively, both p < 0.001), but not new onset HTN and T2DM. In conclusion, serum γ-GT levels not only demonstrated an excellent correlation with the presence of MetS and also in predicting future MetS in adolescents.

A Reappraisal of Testosterone's Binding in Circulation: Physiological and Clinical Implications

In the circulation, testosterone and other sex hormones are bound to binding proteins, which play an important role in regulating their transport, distribution, metabolism, and biological activity. According to the free hormone hypothesis, which has been debated extensively, only the unbound or free fraction is biologically active in target tissues. Consequently, accurate determination of the partitioning of testosterone between bound and free fractions is central to our understanding of how its delivery to the target tissues and biological activity are regulated and consequently to the diagnosis and treatment of androgen disorders in men and women. Here, we present a historical perspective on the evolution of our understanding of the binding of testosterone to circulating binding proteins. On the basis of an appraisal of the literature as well as experimental data, we show that the assumptions of stoichiometry, binding dynamics, and the affinity of the prevailing models of testosterone binding to sex hormone-binding globulin and human serum albumin are not supported by published experimental data and are most likely inaccurate. This review offers some guiding principles for the application of free testosterone measurements in the diagnosis and treatment of patients with androgen disorders. The growing number of testosterone prescriptions and widely recognized problems with the direct measurement as well as the computation of free testosterone concentrations render this critical review timely and clinically relevant.

Lower SHBG level is associated with higher leptin and lower adiponectin levels as well as metabolic syndrome, independent of testosterone

In addition to testosterone (T), the emerging role of sex hormone-binding globulin (SHBG) in pathogenesis of metabolic syndrome (MetS) has been noted recently. However, reports of associations with serum adipocytokine levels are still limited. Therefore, we conducted this study to evaluate whether serum T and SHBG levels are independent predictors for the risk of MetS that are associated with adiponectin and leptin levels in 614 Taiwanese men over 40 years old collected from a free health screening. Subjects in the lowest quartile of TT and SHBG levels are exposed to a 1.58 and 3.22 times risk of developing MetS, as compared to those in the highest quartile of TT and SHBG levels. However, SHBG retains its significance independent of TT as a MetS risk predictor, but not vice versa. In addition, SHBG was significantly correlated with both adiponectin and leptin levels even after adjusting for TT levels. In conclusion, SHBG served as a major predictor for the risk of MetS and was correlated with serum adiponectin and leptin levels that are independent of T. Further studies are needed to elucidate the true role of SHBG in the pathogenesis of MetS and possible mechanisms associated with serum adiponectin and leptin levels.

Modulation of SHBG binding to testosterone and estradiol by sex and morbid obesity

OBJECTIVE

Sex hormone-binding globulin (SHBG) binds and transports testosterone and estradiol in plasma. The possibility that SHBG is a mixture of transporting proteins has been postulated. We analyzed in parallel the effects of obesity status on the levels and binding capacity of circulating SHBG and their relationship with testosterone and estradiol.

DESIGN

Anthropometric measures and plasma were obtained from apparently healthy young (i.e. 35 ± 7 years) premenopausal women (n = 32) and men (n = 30), with normal weight and obesity (BMI >30 kg/m²).

METHODS

SHBG protein (Western blot), as well as the plasma levels of testosterone, estradiol, cortisol and insulin (ELISA) were measured. Specific binding of estradiol and testosterone to plasma SHBG was analyzed using tritium-labeled hormones.

RESULTS

Significant differences in SHBG were observed within the obesity status and gender, with discordant patterns of change in testosterone and estradiol. In men, testosterone occupied most of the binding sites. Estrogen binding was much lower in all subjects. Lower SHBG of morbidly obese (BMI >40 kg/m²) subjects affected testosterone but not estradiol. The ratio of binding sites to SHBG protein levels was constant for testosterone, but not for estradiol. The influence of gender was maximal in morbid obesity, with men showing the highest binding/SHBG ratios.

CONCLUSIONS

The results reported here are compatible with SHBG being a mixture of at least two functionally different hormone-binding globulins, being affected by obesity and gender and showing different structure, affinities for testosterone and estradiol and also different immunoreactivity.

The Utility of Sex Hormone-Binding Globulin in Hypogonadism and Infertile Males

PURPOSE

We sought to determine the role of sex hormone-binding globulin in patients with male infertility.

MATERIALS AND METHODS

We retrospectively reviewed the records of 168 males seen at a fertility clinic from 2012 to 2014 to investigate the accuracy of total testosterone in the biochemical diagnosis of hypogonadism using calculated bioavailable testosterone as the reference value. We used multivariable analysis to assess sex hormone-binding globulin as an independent predictor of infertility.

RESULTS

Computations using calculated bioavailable testosterone as a standard in the measurement of definitive biochemical hypogonadism (less than 156 ng/dl) revealed 81% sensitivity, 83% specificity, 81% positive predictive value and 82% negative predictive value for diagnosing hypogonadism with total testosterone alone. Of the 90 men with total testosterone greater than 300 ng/dl, 20% had low bioavailable testosterone less than 156 ng/dl, 52% had borderline low bioavailable testosterone less than 210 ng/dl and only 48% could be considered biochemically eugonadal according to calculated bioavailable testosterone. Of the 80 patients with total testosterone less than 300 ng/dl, 19% had free testosterone levels greater than 6.5 ng/dl and, thus, could be considered to be eugonadal. By a magnitude similar to that of follicle-stimulating hormone, sex hormone-binding globulin independently predicted decreased sperm concentration (p = 0.0027) and motility (p = 0.0447). After excluding men with azoospermia, only sex hormone-binding globulin levels differed significantly in classically hypogonadal men (group 1-total testosterone less than 300 ng/dl) and those missed but hypogonadal (group 2-calculated bioavailable testosterone less than 210 ng/dl) (p = 0.0001). At a more stringent cutoff of calculated bioavailable testosterone less than 156 ng/dl, sperm motility was significantly different for groups 1 and 2 (p = 0.014).

CONCLUSIONS

Adding sex hormone-binding globulin to total testosterone serum testing facilitates more accurate diagnosis with free testosterone and calculated bioavailable testosterone, and clinical implications of decreased semen parameters to a magnitude similar to that of follicle-stimulating hormone. This warrants further study of the role of sex hormone-binding globulin in male infertility.

Importance of abdominal circumference and body mass index values in predicting male hypogonadism - A practical approach

OBJECTIVE

The objective of this study was to correlate the values of abdominal circumference (AC) and body mass index (BMI) with the levels of total testosterone (TT), free testosterone (FT) and sexual hormone binding globulin (SHBG). We aimed to analyze the association between the anthropometric values and variations in the hormonal levels.

SUBJECTS AND METHODS

A transversal prospective study was conducted. A total of 159 patients were included in the study.

RESULTS

BMI was inversely correlated with TT and SHBG (p = 0.02 and p = 0.006, respectively). AC was also inversely correlated withTT and SHBG (p = 0.006 and p < 0.0001, respectively). However, BMI did not correlate signicantly with these hormonal levels after adjusting for age.

CONCLUSION

This finding led to the conclusion that AC had a stronger inverse correlation than BMI with TT and SHBG. Our data suggested that AC alone can be used as an anthropometric parameter to help simplify the identification of men with low serum TT levels.

Is serum sex hormone-binding globulin a dominant risk factor for metabolic syndrome?

This multi-center, cross-sectional study investigated the association between serum testosterone (T) levels, serum sex hormone-binding globulin (SHBG) levels, and the risk of metabolic syndrome (MS) in 3332 adult Chinese men. The prevalence of MS was 34.7%, and men with MS had lower serum levels of total T (TT) and SHBG than those without MS (P < 0.001). There was no significant difference in serum free T (FT) levels between subjects with and without MS (P = 0.627). In logistic regression analysis, the association between MS and serum SHBG levels persisted after adjusting for age, body mass index (BMI), smoking and drinking status, and serum TT (odds ratio [OR] 0.962, 95% confidence interval [95% CI] 0.954-0.969, P< 0.01). However, the association between serum TT level and the risk of MS was weak after adjusting for age, BMI, SHBG level, and smoking and drinking status (OR 0.981, 95% CI 0.960-1.007). Our study reveals that both serum TT and SHBG levels, but not serum FT, are inversely associated with the prevalence of MS and that serum SHBG is an independent and dominant risk factor for MS.

Increased Body Adiposity and Serum Leptin Concentrations in Very Long-Term Adult Male Survivors of Childhood Acute Lymphoblastic Leukemia

BACKGROUND

We evaluated the body composition and its association with hypogonadism in adult male long-term acute lymphoblastic leukemia (ALL) survivors.

METHODS

The cohort included 49 long-term male ALL survivors and 55 age-matched healthy controls. Fat and lean mass was assessed by dual-energy X-ray absorptiometry; blood biochemistry was obtained for adipokines and testicular endocrine markers.

RESULTS

As compared with controls, the ALL survivors (median age 29 years, range 25-38), assessed 10-28 years after ALL diagnosis, had higher percentages of body (p < 0.05) and trunk fat mass (p < 0.05), and a lower body lean mass (p < 0.001). Survivors had significantly higher levels of leptin and adiponectin and lower levels of insulin-like growth factor-binding protein 3. Body fat mass and percent fat mass correlated with serum leptin and sex hormone-binding globulin (SHBG) levels. Altogether, 15% of the ALL survivors and 9% of age-matched controls were obese (BMI ≥ 30). Obese survivors more often had hypogonadism, had received testicular irradiation, and needed testosterone replacement therapy compared to nonobese survivors.

CONCLUSION

At young adulthood, long-term male ALL survivors have significantly increased body adiposity despite normal weight and BMI. Potential indicators of increased adiposity included high leptin and low SHBG levels. Serum testicular endocrine markers did not correlate with body adiposity.

Metabolic Syndrome: Does it Differ Between Women and Men?

Cardiovascular disease represents a massive healthcare burden worldwide. Gender differences in the pathophysiology, presentation and prognosis of cardiovascular disease have been described in the literature. Metabolic syndrome, characterized by a cluster of metabolic abnormalities is associated with increased risk for type 2 diabetes mellitus and atherosclerotic cardiovascular disease. With the global obesity epidemic, the prevalence of metabolic syndrome is rising rapidly in the developed as well as developing world. However, there is considerable variation in the prevalence based on geography, age, sex and, definition used for diagnosis. Data on gender related differences in metabolic syndrome is relatively scarce. Here, we aim to review the gender differences in epidemiology and pathophysiology of metabolic syndrome as well as its individual components. Knowledge of gender differences in metabolic syndrome can help design gender specific preventative and therapeutic strategies that will have a positive impact on overall population health.

Current medical management of endocrine-related male infertility

Male factor contributes to 50%-60% of overall infertility but is solely responsible in only 20% of couples. Although most male factor infertility is ascertained from an abnormal semen analysis, other male factors can be contributory especially if the sample returns normal. Male infertility can be due to identifiable hormonal or anatomical etiologies that may be reversible or irreversible. This manuscript will highlight existing guidelines and our recommendations for hormone evaluation for male infertility and empiric therapies including multivitamins, estrogen receptor modulators (clomiphene), estrogen conversion blockers (anastrozole), and hormone replacement.

Testosterone concentration and insulin sensitivity in young men with type 1 and type 2 diabetes

OBJECTIVE

Reduced testosterone, a recognized comorbidity of reduced insulin sensitivity (IS) and type 2 diabetes (T2D), has also been reported in adult males with type 1 diabetes (T1D). However, there are limited data on how early reduced testosterone occurs, and whether it is related to the reduced IS in T1D. Leptin, a modulator of the HPG-axis, may also influence testosterone in T1D. We hypothesized that IS and leptin would be associated with total testosterone (TT), and free androgen index (FAI) in adolescent males with T1D.

METHODS

T1D (n = 35), T2D (n = 13), lean (n = 13) and obese (n = 9) adolescent males had IS measured by hyperinsulinemic-euglycemic clamps (glucose infusion rate [GIR]), in addition to leptin, sex hormone binding globulin (SHBG), TT, and FAI. The cohort was stratified into those with T1D (n = 35) and those without (n = 35).

RESULTS

TT and SHBG were lower in T2D boys vs. lean controls, and GIR and leptin correlated with FAI and TT in non-T1D participants. However, despite being insulin resistant, adolescent males with T1D had normal TT and FAI, unrelated to GIR. In T1D, leptin was inversely associated with TT (p = 0.005) and FAI (p = 0.01), independent of puberty, hemoglobin A1c (HbA1c), diabetes duration, body mass index (BMI) z-score and GIR.

CONCLUSION

Leptin accounted for a significant proportion of the variability of testosterone in T1D. However, despite reduced IS, there was no association between IS and testosterone in T1D adolescents. These observations suggest that the mechanisms affecting testosterone may differ between adolescent males with and without T1D.

Association of sex hormone-binding globulin and free testosterone with mortality in men with type 2 diabetes mellitus

OBJECTIVE

Low circulating testosterone levels have been associated with increased mortality in men. We hypothesized that the prognostic role of testosterone in men with type 2 diabetes mellitus (T2DM) is influenced by its carrier protein sex hormone-binding globulin (SHBG).

DESIGN

We conducted a prospective cohort study at a tertiary referral centre.

METHODS

In total, 531 men with T2DM presenting to a diabetes clinic in 2004-2005 were followed prospectively until death, or July 31, 2014, and a survival analysis was performed. The main outcome measure was all cause mortality.

RESULTS

Over a mean (S.D.) follow up of 7.6 years (2.6) 175 men (33%) died. In Cox proportional hazard models both higher SHBG (Hazard Ratio (HR) 1.012 (95% CI 1.002-1.022), P=0.02) and lower calculated free testosterone (cFT) (HR 0.995 (95% CI 0.993-0.998), P=0.001) were risk factors for all cause mortality independently of age, BMI, presence of macro- and microvascular disease, duration of T2DM, hemoglobin, renal function, insulin use, C-reactive protein and homeostatic model of insulin resistance. By contrast, the inverse association of total testosterone (TT) with mortality weakened after these adjustments (P=0.11). SHBG remained associated with mortality (P<0.001) both if substituted for or added to TT in the multivariable model. In the fully adjusted model, an increase of SHBG by 17.3 nmol/l (1 S.D.) increased mortality by 22% and a decrease in cFT by 81 pmol/l (1 S.D.) increased mortality by 45%.

CONCLUSIONS

The association of SHBG with mortality in men with T2DM is novel. Whether SHBG acts via regulation of testosterone, has intrinsic biological roles, or is a marker of poor health requires further study.