Interrelations between sex hormone-binding globulin (SHBG), plasma lipoproteins and cardiovascular risk

Quantitative proteomics identifies plasma protein alterations that associate with metabolic and thrombotic profile changes after bariatric surgery

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) surgery has been shown to lead to favourable health outcomes in obese patients. However, the molecular changes that occur and how they relate to clinical measures are poorly understood. Here, we characterise the proteomic alterations that occur in plasma of RYGB patients before and 9 months after surgery using quantitative proteomics.

METHODS

Plasma proteomics was performed by sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) to identify and quantify differentially abundant proteins. Relationships between significantly altered proteins and clinical markers were examined. A gene set enrichment analysis was also conducted to identify altered pathways.

RESULTS

From the proteomic analysis, 27 proteins increased, and 43 proteins decreased in abundance 9 months after surgery, providing insights into the physiological changes that accompany weight loss. Proteins including sex hormone binding globulin (SHBG), inter-alpha-trypsin inhibitor heavy chain 3 (ITIH3) and apolipoprotein D (APOD), which increased in abundance post-surgery, highlight improvements in lipid regulation, insulin sensitivity and inflammation. Proteins involved in coagulation, including α2-macroglobulin, kallikrein-B1, prothrombin, and factor (FX, FXI and FXII), exhibited reduced levels, aligning with a decrease in thrombotic potential.

CONCLUSIONS

These findings provide a mechanistic understanding of how bariatric surgery leads to systemic changes in metabolic and haemostatic pathways, thus favourably modulating the risk of developing cardiovascular disease.

Blood lipid levels mediating the effects of sex hormone-binding globulin on coronary heart disease: Mendelian randomization and mediation analysis

Observational studies indicate that serum sex hormone-binding globulin (SHBG) levels are inversely correlated with blood lipid levels and coronary heart disease (CHD) risk. Given that dyslipidemia is an established risk factor for CHD, we aim to employ Mendelian randomization (MR) in conjunction with mediation analysis to confirm the mediating role of blood lipid levels in the association between SHBG and CHD. First, we assessed the causality between serum SHBG levels and five cardiovascular diseases using univariable MR. The results revealed causality between SHBG levels and reduced risk of CHD, myocardial infarction, as well as hypertension. Specifically, the most significant reduction was observed in CHD risk, with an odds ratio of 0.73 (95% CI 0.63-0.86) for each one-standard-deviation increase in SHBG. The summary-level data of serum SHBG levels and CHD are derived from a sex-specific genome-wide association study (GWAS) conducted by UK Biobank (sample size = 368,929) and a large-scale GWAS meta-analysis (60,801 cases and 123,504 controls), respectively. Subsequently, we further investigated the mediating role of blood lipid level in the association between SHBG and CHD. Mediation analysis clarified the mediation proportions for four mediators: high cholesterol (48%), very low-density lipoprotein cholesterol (25.1%), low-density lipoprotein cholesterol (18.5%), and triglycerides (44.3%). Summary-level data for each mediator were sourced from the UK Biobank and publicly available GWAS. The above results confirm negative causality between serum SHBG levels and the risk of CHD, myocardial infarction, and hypertension, with the causal effect on reducing CHD risk largely mediated by the improvement of blood lipid profiles.

The relationship between serum manganese concentration with all-cause and cause-specific mortality: a retrospective and population-based cross-sectional study

BACKGROUND

The study aimed to explore the association between manganese concentration and all-cause, cardiovascular disease (CVD)-related, and cancer-related mortality in the general population of the United States.

METHODS

We integrated the data from the National Health and Nutrition Examination Survey from 2011 to 2018. A total of 9,207 subjects were selected based on the inclusion and exclusion criteria. The relationship between manganese concentration and all-cause, CVD-related, and cancer-related mortality was analyzed by constructing a Cox proportional hazard regression model and a restricted cubic spline (RCS) plot. Additionally, subgroup analyses stratified by age, sex, race/ethnicity, hypertension, diabetes mellitus (DM), chronic heart disease, chronic heart failure, angina pectoris, heart attack, stroke, and BMI were further performed.

RESULTS

In the full adjusted model, compared with the lowest quartile, the adjusted hazard ratios with 95% confidence intervals (CIs) for all-cause, CVD-related, and cancer-related mortality across manganese quartiles were (1.11 (0.87,1.41), 0.96 (0.74, 1.23), and 1.23 (0.96, 1.59); P-value for trend =0.041), (0.86 (0.54, 1.37), 0.87 (0.55, 1.40), and 1.07 (0.67, 1.72); P-value for trend =0.906), and (1.45 (0.92, 2.29), 1.14 (0.70, 1.88), and 1.26 (0.75, 2.11); P-value for trend =0.526), respectively. The RCS curve shown a U-shaped association between manganese concentration and all-cause mortality and CVD-related mortality (P-value for nonlinear <0.05). However, there was an increase and then a decrease in the link between manganese concentration and cancer-related mortality (P-value for nonlinear <0.05). Manganese exposure was positively correlated with sex (correlation coefficient, r =0.19, P-value <0.001) and negatively correlated with age (correlation coefficient, r =-0.11, P-value <0.001) and serum creatinine (correlation coefficient, r =-0.12, P-value <0.001), respectively.

CONCLUSIONS

Our findings suggest that elevated serum manganese concentrations are associated with all-cause and CVD-related mortality in the U.S. population and that maintenance of serum manganese between 8.67-9.23 µg/L may promote public health.

Gender Differences in the Prevalence and Clinical Correlates of Metabolic Syndrome in First-Episode and Drug-Naïve Patients With Major Depressive Disorder

OBJECTIVE

Major depressive disorder (MDD) is a severe psychiatric symptom worldwide, and the coexistence of MDD with metabolic syndrome (MetS) is common in clinical practice. However, gender differences in comorbid MetS in first-episode and drug-naïve (FEDN) MDD patients have not been reported. Here, we explored potential gender differences in the prevalence and clinical correlates of comorbid MetS in FEDN MDD patients.

METHODS

A cross-sectional study of 1718 FEDN MDD patients was conducted. Demographic and clinical data were collected. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale, and Positive and Negative Syndrome Scale positive subscale were used to evaluate depression, anxiety, and psychotic symptoms, respectively.

RESULTS

The prevalence of MetS was 1.645-fold higher in female MDD patients (38.50%) than in male patients (26.53%). Patients with MetS had higher HAMD score, Hamilton Anxiety Scale score, and Positive and Negative Syndrome Scale positive subscale score than patients without MetS (p values < .001). Furthermore, suicide attempts (male: odds ratio [OR] = 1.706, p = .034; female: OR = 1.639, p = .004) and HAMD score (male: OR = 1.251, p < .001; female: OR = 1.148, p < .001) were independently associated with MetS in male and female patients, whereas age of onset was independently associated with MetS only in female patients (OR = 1.744, p = .047).

CONCLUSIONS

Our findings suggest significant gender differences in the prevalence and clinical correlates of comorbid MetS in FEDN MDD patients. Clinical variables (suicide attempts and HAMD scores) may be independently associated with MetS in MDD patients.

[Beyond NICE: Updated Systematic Review on the Current Evidence of Using Puberty Blocking Pharmacological Agents and Cross-Sex-Hormones in Minors with Gender Dysphoria]

Beyond NICE: Updated Systematic Review on the Current Evidence of Using Puberty Blocking Pharmacological Agents and Cross-Sex-Hormones in Minors with Gender Dysphoria Abstract: Objective: The suppression of physiological puberty using puberty-blocking pharmacological agents (PB) and prescribing cross-sex hormones (CSH) to minors with gender dysphoria (GD) is a current matter of discussion, and in some cases, PB and CSH are used in clinical practice for this particular population. Two systematic reviews (one on PB, one on CSH treatment) by the British National Institute for Clinical Excellence (NICE) from 2020 indicated no clear clinical benefit of such treatments regarding critical outcome variables. In particular, these two systematic NICE reviews on the use of PB and CSH in minors with GD detected no clear improvements of GD symptoms. Moreover, the overall scientific quality of the available evidence, as discussed within the above-mentioned two NICE reviews, was classified as "very low certainty" regarding modified GRADE criteria. Method: The present systematic review presents an updated literature search on this particular topic (use of PB and CSH in minors with GD) following NICE principles and PICO criteria for all relevant new original research studies published since the release of the two above-mentioned NICE reviews (updated literature search period was July 2020-August 2023). Results: The newly conducted literature search revealed no newly published original studies targeting NICE-defined critical and important outcomes and the related use of PB in minors with GD following PICO criteria. For CSH treatment, we found two new studies that met PICO criteria, but these particular two studies had low participant numbers, yielded no significant additional clear evidence for specific and clearly beneficial effects of CSH in minors with GD, and could be classified as "low certainty" tfollowing modified GRADE criteria. Conclusions: The currently available studies on the use of PB and CSH in minors with GD have significant conceptual and methodological flaws. The available evidence on the use of PB and CSH in minors with GD is very limited and based on only a few studies with small numbers, and these studies have problematic methodology and quality. There also is a lack of adequate and meaningful long-term studies. Current evidence doesn't suggest that GD symptoms and mental health significantly improve when PB or CSH are used in minors with GD. Psychotherapeutic interventions to address and reduce the experienced burden can become relevant in children and adolescents with GD. If the decision to use PB and/or CSH is made on an individual case-by-case basis and after a complete and thorough mental health assessment, potential treatment of possibly co-occurring mental health problems as well as after a thoroughly conducted and carefully executed individual risk-benefit evaluation, doing so as part of clinical studies or research projects, as currently done in England, can be of value in terms of generation of new research data. The electronic supplement (ESM) 1 is an adapted and abreviated English version of this work.

Reproductive risk factors across the female lifecourse and later metabolic health

Metabolic health is characterized by optimal blood glucose, lipids, cholesterol, blood pressure, and adiposity. Alterations in these characteristics may lead to the development of type 2 diabetes mellitus or dyslipidemia. Recent evidence suggests that female reproductive characteristics may be overlooked as risk factors that contribute to later metabolic dysfunction. These reproductive traits include the age at menarche, menstrual irregularity, the development of polycystic ovary syndrome, gestational weight change, gestational dysglycemia and dyslipidemia, and the severity and timing of menopausal symptoms. These risk factors may themselves be markers of future dysfunction or may be explained by shared underlying etiologies that promote long-term disease development. Disentangling underlying relationships and identifying potentially modifiable characteristics have an important bearing on therapeutic lifestyle modifications that could ease long-term metabolic burden. Further research that better characterizes associations between reproductive characteristics and metabolic health, clarifies underlying etiologies, and identifies indicators for clinical application is warranted in the prevention and management of metabolic dysfunction.

Androgenicity in Young Women and Development of Metabolic Syndrome Before Menopause: The CARDIA and CARDIA Women's Studies

Context

There are no reported data from prospective long-term studies on the relation of androgen levels in young women with development of metabolic syndrome (MetS) before menopause.

Objective

We investigated associations of androgens and SHBG with incident MetS during 23 years of follow-up.

Methods

We included 366 White and 375 Black women ages 20 to 32 years participating in the CARDIA study and CARDIA Women's study, free of MetS at baseline examination (1987-1988), and premenopausal 23 years later. Androgens and SHBG were categorized into quartiles. MetS was defined according to the American Heart Association/National Heart, Lung, and Blood Institute 2009 Joint Scientific Statement. Cox proportional hazards models were used.

Results

By year 23, 30% of women developed MetS. Adjusting for baseline age, race, and education, hazard ratios (95% CI) of developing MetS were 1.46 (1.02-2.10) and 2.22 (1.53-3.21) for women in the highest vs lowest total testosterone (T) and free T quartile, respectively. The hazards of developing MetS were 47%, 59%, and 53% lower for women with SHBG in the second, third, and fourth quartiles (vs lowest quartile), respectively. Associations were attenuated for total T with further adjustments for smoking, physical activity, menstrual status, oral contraceptive/hormone (OCHM) use, insulin level, oligomenorrhea, and age at menarche, but remained statistically significant for free T and SHBG. Associations were similar for both Blacks and Whites, and OCHM nonusers, but not for OCHM users.

Conclusion

High androgenicity in young premenopausal women is associated with higher risk of future MetS, suggesting that early assessment of androgens may contribute to prevention.

Sex Hormone-Binding Globulin and Risk of Coronary Heart Disease in Men and Women

BACKGROUND

The role of sex hormone-binding globulin (SHBG) levels in clinical risk stratification and intervention for coronary heart disease (CHD) remains uncertain. We aimed to examine whether circulating levels of SHBG are predictive of CHD risk in men and women.

METHODS

We investigated the association between SHBG and the risk of incident CHD in 128 322 men and 135 103 women free of CHD at baseline in the prospective United Kingdom Biobank (UKB) cohort. The unconfounded associations were estimated using Mendelian randomization (MR) analysis. We further conducted a meta-analysis to integrate currently available prospective evidence. CHD events included nonfatal and fatal myocardial infarction and coronary revascularization.

RESULTS

In the UKB, during a median of 11.7 follow-up years, 10 405 men and 4512 women developed CHD. Serum levels of SHBG were monotonically associated with a decreased risk of CHD in both men (adjusted hazard ratio [HR] per log nmol/L increase in SHBG: 0.88 [0.83-0.94]) and women (HR: 0.89 [0.83-0.96]). MR-based analyses suggested causality and a dose-response relationship of SHBG with CHD risk. A cumulative meta-analysis including 216 417 men and 138 282 women from 11 studies showed that higher levels of SHBG were prospectively associated with decreased CHD risk in men comparing the highest with the lowest quartile: pooled relative risk (RR) 0.81 (0.74-0.89) and women (pooled RR: 0.86 [0.78-0.94]).

CONCLUSIONS

Higher circulating SHBG levels were directly and independently predictive of lower CHD risk in both men and women. The utility of SHBG for CHD risk stratification and prediction warrants further study.

Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology

According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC-MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.

Associations between endogenous sex hormone levels and adipokine levels in the Multi-Ethnic Study of Atherosclerosis

Background

Differences in sex hormone levels contribute to differences in cardiovascular disease (CVD) risk. Adipokines play a role in cardiometabolic pathways and have differing associations with CVD. Adipokine levels differ by sex; however, the association between sex hormone profiles and adipokines is not well established. We hypothesized that a more androgenic sex hormone profile would be associated with higher leptin and resistin and lower adiponectin levels among postmenopausal women, with the opposite associations in men.

Methods

We performed an analysis of 1,811 adults in the Multi-Ethnic Study of Atherosclerosis who had both sex hormones and adipokines measured an average of 2.6 years apart. Sex hormones [Testosterone (T), estradiol (E2), sex hormone binding globulin (SHBG), and dehydroepiandrosterone (DHEA)] were measured at exam 1; free T was estimated. Serum adipokines (leptin, resistin, adiponectin) were measured at exams 2 or 3. We used multivariable linear regression to examine the cross-sectional associations between sex hormones and adipokines.

Results

The mean (SD) age was 63 (10) years, 48% were women; 59% non-White participants. For leptin, after adjusting for demographics only, higher free T and lower SHBG, were associated with higher leptin in women; this association was attenuated after further covariate adjustment. However in men, higher free T and lower SHBG were associated with greater leptin levels in fully adjusted models. For adiponectin, lower free T and higher SHBG were associated with greater adiponectin in both women and men after adjustment for CVD risk factors. For resistin, no significant association was found women, but an inverse association with total T and bioT was seen in men.

Conclusion

Overall, these results further suggest a more androgenic sex profile (higher free T and lower SHBG) is associated with a less favorable adipokine pattern. These findings may provide mechanistic insight into the interplay between sex hormones, adipokines, and CVD risk.

Integrative analysis of the plasma proteome and polygenic risk of cardiometabolic diseases

Cardiometabolic diseases are frequently polygenic in architecture, comprising a large number of risk alleles with small effects spread across the genome1-3. Polygenic scores (PGS) aggregate these into a metric representing an individual's genetic predisposition to disease. PGS have shown promise for early risk prediction4-7 and there is an open question as to whether PGS can also be used to understand disease biology8. Here, we demonstrate that cardiometabolic disease PGS can be used to elucidate the proteins underlying disease pathogenesis. In 3,087 healthy individuals, we found that PGS for coronary artery disease, type 2 diabetes, chronic kidney disease and ischaemic stroke are associated with the levels of 49 plasma proteins. Associations were polygenic in architecture, largely independent of cis and trans protein quantitative trait loci and present for proteins without quantitative trait loci. Over a follow-up of 7.7 years, 28 of these proteins associated with future myocardial infarction or type 2 diabetes events, 16 of which were mediators between polygenic risk and incident disease. Twelve of these were druggable targets with therapeutic potential. Our results demonstrate the potential for PGS to uncover causal disease biology and targets with therapeutic potential, including those that may be missed by approaches utilizing information at a single locus.

Classic and Novel Sex Hormone Binding Globulin Effects on the Cardiovascular System in Men

In men, 70% of circulating testosterone binds with high affinity to plasma sex hormone binding globulin (SHBG), which determines its bioavailability in their target cells. In recent years, a growing body of evidence has shown that circulating SHBG not only is a passive carrier for steroid hormones but also actively regulates testosterone signaling through putative plasma membrane receptors and by local expression of androgen-binding proteins apparently to reach local elevated testosterone concentrations in specific androgen target tissues. Circulating SHBG levels are influenced by metabolic and hormonal factors, and they are reduced in obesity and insulin resistance, suggesting that SHBG may have a broader clinical utility in assessing the risk for cardiovascular diseases. Importantly, plasma SHBG levels are strongly correlated with testosterone concentrations, and in men, low testosterone levels are associated with an adverse cardiometabolic profile. Although obesity and insulin resistance are associated with an increased incidence of cardiovascular disease, whether they lead to abnormal expression of circulating SHBG or its interaction with androgen signaling remains to be elucidated. SHBG is produced mainly in the liver, but it can also be expressed in several tissues including the brain, fat tissue, and myocardium. Expression of SHBG is controlled by peroxisome proliferator-activated receptor γ (PPARγ) and AMP-activated protein kinase (AMPK). AMPK/PPAR interaction is critical to regulate hepatocyte nuclear factor-4 (HNF4), a prerequisite for SHBG upregulation. In cardiomyocytes, testosterone activates AMPK and PPARs. Therefore, the description of local expression of cardiac SHBG and its circulating levels may shed new light to explain physiological and adverse cardiometabolic roles of androgens in different tissues. According to emerging clinical evidence, here, we will discuss the potential mechanisms with cardioprotective effects and SHBG levels to be used as an early metabolic and cardiovascular biomarker in men.

The relationship between components of metabolic syndrome and plasma level of sex hormone-binding globulin

Plasma concentration of sex hormone-binding globulin (SHBG), as an androgen binding protein, is impressed by many physiological and environmental factors. Recent studies have shown that plasma level of SHBG is related to some components of metabolic syndrome (MetS); however, in contrast, few articles failed to show any associations between SHBG and MetS. So, this study was conducted to investigate the relationship between Components of Metabolic Syndrome and Plasma Level of Sex Hormone-Binding Globulin. In this study, after measuring the plasma level of SHBG in 84 individuals, the relation between MetS and the plasma level of SHBG was investigated. After evaluating the plasma level of SHBG and metabolic abnormalities in men and women, we investigated the factors which mentioned above in two groups including patients with and without MetS. Also, the metabolic abnormalities which evaluated in this study including plasma level of 25-hydroxyvitamin D, serum uric acid (SUA), Albumin, lipid profiles and etc. according to five components of MetS. Our result shows that SHBG could contributed to some laboratory parameters such as LDL-C (P<0.05), total cholesterol (P<0.05), triglycerides (P<0.05) and etc. in men, but not in women. On the other hand, we observed that concentration of SHBG is higher in patients with MetS (P<0.05); however, results from our experiment showed that there is no relation between lower level of SHBG and five components of MetS such as central obesity, raised fasting plasma glucose (FPG) (P>0.05), reduced HDL-C (P>0.05), raised triglycerides (P>0.05) and raised blood pressure (P>0.05) in both men and women. There is a significant association between SHBG and Log-Hip Circumference (P<0.05), Non-HDL-C (P<0.05) and Log-25(OH)D (P<0.05) was seen in this cross-section study in both men and women. Results obtained from our study suggest that SHBG is not a powerful enough factor to use as a predictor of MetS alone and there is no association between plasma level of SHBG and development of five components of MetS, however, lower SHBG level may contributed to lipid profiles.

Genetic polymorphisms of the SHBG gene can be the effect on SHBG and HDL-cholesterol levels in Coronary Heart Disease: a case-control study

Sex hormone binding globulin (SHBG) level is positively associated with the high-density lipoprotein cholesterol (HDL-C) levels. The aim of this study was to investigate the effects of the SHBG gene variations (D356N, rs1799941, and P156L) on SHBG and HDL-C levels and Coronary Heart Disease (CHD) risk. The SHBG D356 N (rs6259,G > A), P156L (rs6258,C > T), and rs1799941(G > A) polymorphisms were determined in 131 male CHD patients and 55 male controls by PCR-RFLP and real-time PCR techniques. SHGB levels were measured by Electro-chemiluminescence immunoassay (ECLIA). In the patients who had SHBG levels lower than threshold 35 nmol/l value, the risk of being HDL-C levels lower than threshold 0.90 mmol/l value was observed statistically significant (p = 0.017; OR 2.522, 95% CI 1.170-5.438). The rs1799941 GG was associated with increased CHD risk when compared with the A allele carriers (GA + AA) (p = 0.019, OR 2.222, 95% CI 1.130-4.371). In addition, the rs1799941 GG genotype and D356 N N allele were associated with lower SHBG in the CHD group (p < 0.01). The logistic regression analysis also revealed the rs1799941 GG genotype was significantly associated with low SHBG in CHD patients. It was observed that Haplotype-1(rs1799941 G allele-P156L P allele-D356 N D allele) was associated with increased CHD risk, while Haplotype-2 (rs1799941 rare A allele-P156L C allele- D356 N G allele) was correlated with the decreased CHD risk (p = 0.0167). Our findings suggest that there is a positive correlation between SHBG and HDL-C levels in CHD patients, and this association might be affected by SHBG gene variations.

Low Levels of Sex Hormone-Binding Globulin Constitute an Independent Risk Factor for Arterial Stiffness in Korean Women

The association between sex hormone-binding globulin (SHBG) and arterial stiffness in women is not conclusive. In addition, obesity might also be involved in the relationship between SHBG and atherosclerosis. The aim of this study was to determine the relationship between SHBG and arterial stiffness in association with central obesity in women. This cross-sectional study included 381 women who participated in the health checkup programs in one hospital. The brachial-ankle pulse wave velocity (baPWV) was measured as a marker for arterial stiffness. A negative correlation was observed between SHBG levels and baPWV (rho = -0.281). The relationship was significant even after adjusting for potential confounders (beta = -0.087 in fully adjusted model). After considering the interaction between central obesity and SHBG levels, the significant association was evident only in obese women (P for interaction = 0.025). Adjustment for a 10-year atherosclerotic cardiovascular disease (ASCVD) risk scores, instead of each cardiovascular risk factor individually, did not affect the significance of the relationship between SHBG levels and baPWV. Serum levels of SHBG were negatively associated with arterial stiffness independent of cardiovascular risk factors or 10-year ASCVD risk scores in Korean women. The relationship may be potentiated by central obesity.

Metabolic syndrome in patients with prostate cancer undergoing intermittent androgen-deprivation therapy

INTRODUCTION

The presence of metabolic syndrome in men with prostate cancer (PCa) undergoing androgen-deprivation therapy (ADT), especially intermittent type, has not been completely evaluated. The aim of this study is to evaluate metabolic syndrome in men with PCa undergoing intermittent ADT.

METHODS

In this longitudinal study, we studied the prevalence of metabolic syndrome and its components in 190 patients who were undergoing intermittent ADT. The metabolic syndrome was defined according to the Adult Treatment Panel III criteria. All metabolic parameters, including lipid profile, blood glucose, blood pressures, and waist circumferences of the patients were measured six and 12 months after treatment.

RESULTS

Mean age of the patients was 67.5 ± 6.74 years. The incidence of metabolic syndrome after six and 12 months was 6.8% and 14.7%, respectively. Analysis of various components of the metabolic syndrome revealed that patients had significantly higher overall prevalence of hyperglycemia, abdominal obesity, and hypertriglyceridemia in their six- and 12-month followups, but blood pressure has not been changed in the same period except for diastolic blood pressure after six months.

CONCLUSIONS

Although there was an increased risk of metabolic syndrome in patients receiving intermittent ADT, it was lower than other studies that treated the same patients with continuous ADT. Also it seems that intermittent ADT has less metabolic complications than continuous ADT and could be used as a safe alternative in patients with advanced and metastatic PCa.

Gender-specific associations of serum sex hormone-binding globulin with features of metabolic syndrome in children

BACKGROUND

Sex hormone-binding globulin (SHBG) has been proposed as a biomarker of MetS in children and adults. We aim to determine the associations of SHBG with components of MetS in children from the Middle-East where the prevalence of MetS are on the rise.

METHODS

In this cross-sectional study, a total of 509 randomly selected school children (226 boys and 283 girls) aged 12-16 years were recruited. Fasting blood glucose and lipid profile were determined using routine laboratory procedures. Serum SHBG is measured with Cobas e411 using an electrochemiluminescence immunoassay. The modified definition of ATP-III (NHANES III) was used for the diagnosis of MetS.

RESULTS

Among 509 children, 23.4 % had metabolic syndrome. Boys had a significantly higher waist circumference and systolic blood pressure (p < 0.032, 0.024, respectively) than girls, while levels of glucose (p < 0.029), and SHBG (p < 0.003) were significantly higher in girls than in boys. In overall population, a significant inverse correlation of SHBG level with age, BMI, systolic blood pressure and triglycerides and a significant direct correlation between SHBG level and HDL-c was exhibited. Children with the lowest tertile of serum SHBG had significantly higher prevalence of MetS (p < 0.05). ROC curve shows SHBG level as more sensitive marker of MetS in boys (AUC = 0.70, p < 0.001).

CONCLUSIONS

Serum SHBG is significantly more sensitive in identifying MetS in boys, not girls, indicating gender dimorphism.

Neighborhood socioeconomic status during childhood versus puberty in relation to endogenous sex hormone levels in adult women

BACKGROUND

Socioeconomic adversity in early life is related to cardiovascular risk in adulthood; however, no studies have examined whether such adversity may be related to endogenous sex hormones, which are themselves associated with cardiovascular outcomes, or whether the timing of adversity exposures (childhood vs. puberty) matters.

OBJECTIVE

The goal of the current study was to separately examine neighborhood socioeconomic status (SES) during periods of childhood and puberty in relation to adulthood levels of endogenous sex hormones (estradiol [E2], testosterone), sex hormone binding globulin (SHBG), and a derived index of bioavailable testosterone (free androgen index).

METHODS

In a sample of 143 premenopausal women (mean age = 36.8 [SD = 5.5]; 51.7% White, 32.2% African American, 5.6% Latina, 7.0% Chinese, and 3.5% Filipina), retrospective reports of residential address information in designated periods of childhood and puberty were used to derive U.S. census-based neighborhood SES composite scores characterizing the socioeconomic environments of women during these periods.

RESULTS

In covariate-adjusted analyses, higher neighborhood SES in puberty predicted higher levels of SHBG in adulthood, but neighborhood SES during childhood did not (standardized regression coefficient = .24, p = .01 vs. standardized regression coefficient = .04, p = .75, respectively). Neighborhood SES was not predictive of other hormones (E2, testosterone, and free androgen index).

DISCUSSION

The current findings suggest that puberty may be a time of particular vulnerability to the effects of neighborhood SES on SHBG levels, which have been linked to cardiovascular risk factor profiles and atherosclerotic disease progression.

Immunologic and mass-spectrometric estimates of SHBG concentrations in healthy women

OBJECTIVE

Sex-hormone binding globulin (SHBG) concentrations across the adult female lifespan are not well defined. To address this knowledge gap, SHBG was quantified by both immunological and criterion methods, viz, mass spectrometry (MS).

SETTING

Center for Translational Science Activities (CTSA).

PARTICIPANTS

Healthy nonpregnant women (N=120) ages 21 to 79 years.

OUTCOMES

SHBG, testosterone (T), estradiol (E2) and estrone (E1) each determined by MS. Uni- and multivariate regression of SHBG concentrations on age, body mass index (BMI), total and visceral abdominal fat (TAF, AVF), albumin, glucose, insulin, sex steroids, selected cytokines, blood pressure, and lipids.

RESULTS

By univariate regression, MS-estimated SHBG correlated negatively with BMI, TAF, AVF, insulin, free T and bioavailable T (bio T) (each P≤10(-4)), but not with blood pressure or lipids. By stepwise multivariate regression analysis, free and total T (both positive) and bio T (negative) were correlated with SHBG in all 4 assays (each P<10(-15), R(2)≥0.481). In addition, TAF and BMI were negatively associated with SHBG (P≤0.0066) in 2 SHBG assays, and estrone and IL-8 with SHBG weakly (P≤0.035) in one SHBG assay each. When nonsignificant cytokines were excluded, SHBG was jointly associated with AVF, total T and HDL (P<10(-9), R(2)=0.358).

CONCLUSION

According to MS, three metabolic factors, T, AVF and HDL, together explain more than one-third of the interindividual variation in SHBG levels. We speculate that these measures reflect insulin action.

Serum sex hormone-binding globulin and testosterone in relation to cardiovascular disease risk factors in young men: a population-based study

OBJECTIVE

Reduced sex hormone-binding globulin (SHBG) concentration predicts insulin resistance and type 2 diabetes, but its association with cardiovascular disease (CVD) risk is unclear. We examined the association between SHBG and cardiovascular risk factors, independently of total testosterone (TT), in young men.

DESIGN

Observational, cross-sectional study.

SETTING

General community.

PARTICIPANTS

The study included 2716 men aged 31 years in the Northern Finland Birth Cohort in 1996 with clinical examination data and fasting blood samples.

OUTCOME VARIABLES

Blood pressure (BP), lipids and C-reactive protein (CRP) as biological CVD risk markers.

RESULTS

SHBG concentration was significantly and inversely related to systolic and diastolic BP, triglycerides and CRP, but positively to HDL cholesterol after adjusting for insulin, BMI, waist circumference, smoking, education and physical activity (all P<0.05). These linearly graded associations persisted with additional adjustment for TT. SHBG was significantly associated with total cholesterol only with adjustment for covariates and TT (P<0.05). The direction and magnitude of associations between TT and risk factors were variable, but further adjustment for insulin, adiposity and SHBG showed positive associations between TT and BP, total and LDL-cholesterol and triglycerides and an inverse association with CRP (all P<0.05), but its relation with HDL-cholesterol was no longer significant.

CONCLUSIONS

In this cohort of young adult men, higher SHBG concentration was associated with a more favourable CVD risk profile, independently of TT. SHBG concentration modified the associations of TT with CVD risk factors.

Androgenic sex steroids contribute to metabolic risk beyond intra-abdominal fat in overweight/obese black and white women

OBJECTIVE

To determine the independent contribution of androgenic sex hormones beyond visceral adipose tissue (VAT) on metabolic risk.

DESIGN AND METHODS

A cross-sectional evaluation of 66 (36 white and 30 black) premenopausal overweight/obese women using multiple regression analyses to determine the independent effects of sex hormone-binding globulin (SHBG), total testosterone (TT), and free testosterone using the free androgen index (FAI) on metabolic variables above VAT.

RESULTS

SHBG contributed to the variance in insulin (P = 0.003), insulin resistance using HOMA-IR (P = 0.006), and high-density lipoprotein cholesterol2 (P = 0.029). TT contributed to the variance in systolic and diastolic blood pressure (P < 0.001), total cholesterol (P = 0.003), low-density lipoprotein cholesterol (P = 0.003), and apolipoprotein B (P = 0.004). FAI contributed to the variance in the greatest number of metabolic variables beyond VAT. There was also a significant race-FAI interaction for fasting glucose (P = 0.013). A Pearson's correlation coefficient showed a significant relationship between FAI and glucose in white women (r = 0.48, P = 0.003) while showing no relationship in black women (r = -0.01, P = 0.941).

CONCLUSIONS

Our study showed that androgenic sex steroids contributed significantly to the variance in metabolic variables associated with health risk. However, they do not provide sufficient information relevant to glucose status in black women.

Screening for diabetes and cardiometabolic disease in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a significant risk factor for developing type 2 diabetes and increased cardiovascular disease risk (together referred to as ‘cardiometabolic disease’, CMD). Primary prevention of CMD may be possible in women with PCOS but the diagnostic criteria for PCOS are controversial and this often hampers optimal clinical management. PCOS affects as many as 18% of women of reproductive age, and at least 70% remain undiagnosed in primary care. Screening women with PCOS for diabetes is seldom undertaken, largely through difficulties in diagnosis due to identification and management of PCOS continuing to focus on treatment of infertility and hirsutism. This article focuses on the diagnostic challenges of making the initial diagnosis of PCOS and considers how screening, detection and prevention of CMD might become routine clinical practice. It explores the unique challenges associated with PCOS and highlights the need for better evidence to justify screening and intervention. Finally, a pragmatic approach to assessing women with PCOS is suggested for use within primary care.

Sex hormone binding globulin, free estradiol index, and lipid profiles in girls with precocious puberty

PURPOSE

Sex hormone-binding globulin (SHBG) modulates the availability of biologically active free sex hormones. The regulatory role of SHBG might be important in the relationship between hormone levels and the modification of lipid profiles in girls with precocious puberty. However, few studies have evaluated the relationship of SHBG, free estradiol index (FEI), and lipid levels in these girls.

METHODS

One hundred and nine girls less than 8 years of age with pubertal development were enrolled. FEI was calculated with SHBG and estradiol (E2). We analyzed SHBG between peak luteinizing hormone (LH)≥5 (IU/L) (group 1) and LH<5 (IU/L) (group 2) through a gonadotropin releasing hormone stimulation test.

RESULTS

Body mass index (BMI) standard deviation score (SDS) was higher in group 2 than in group 1 (P=0.004). Serum SHBG levels did not differ and FEI was not higher in group 1 (P=0.122). Serum cholesterol, HDL, and LDL did not differ; however, triglyceride levels were higher in group 2 (P=0.023). SHBG was negatively correlated with bone age advancement, BMI, BMI SDS, and FEI, and was positively correlated with HDL. However, SHBG was not correlated with E2 or peak LH.

CONCLUSION

Serum SHBG itself might not be associated with precocious puberty in girls, but it might be related to BMI and lipid profiles. Further studies are needed to reveal the relationship between sex hormone and obesity in girls with precocious puberty.

Inverse association between serum insulin and sex hormone-binding globulin in a population survey in Sweden

OBJECTIVES

Obesity is associated with low levels of sex hormone-binding globulin (SHBG). While the reason is not fully understood, we aimed to study the association between serum insulin and levels of SHBG in a random population.

DESIGN AND METHODS

Between 2001 and 2005, a random sample of 2816 participants aged 30-74 years were enrolled in a cross-sectional survey in the South-west of Sweden. Fasting blood samples were collected and an oral glucose tolerance test (OGTT) was conducted in all subjects without known diabetes. Diabetes mellitus was defined according to criteria from WHO, and clinical characteristics were used to discriminate between type 1 (T1D) and type 2 diabetes (T2D). Analyses of SHBG were successful in 2782 participants (98%), who thus constituted the current study population.

RESULTS

WE FOUND SIGNIFICANT INVERSE ASSOCIATION BETWEEN LEVELS OF SHBG AND FASTING SERUM INSULIN IN BOTH GENDERS (MEN: β=-0.090, P=0.001; women: β=-0.197, P<0.001), which was independent of differences in age and BMI. The associations remained when also differences in fasting plasma glucose were accounted for (men: β=-0.062, P=0.022; women: β=-0.176, P≤0.001). Subjects with T1D exhibited higher levels of SHBG than both T2D (men: δ=15.9 nmol/l, P<0.001; women: δ=71.1 nmol/l, P<0.001) and non-diabetic subjects (men: δ=15.1 nmol/l, P<0.001; women: δ=72.9 nmol/l, P<0.001) independent of age, BMI and fasting glucose levels.

CONCLUSION

These findings are consistent with high levels of SHBG in T1D, and correspondingly low levels in T2D subjects, suggesting an inhibitory effect of insulin on the SHBG production in the liver.

Dietary supplementation with fish gelatine modifies nutrient intake and leads to sex-dependent responses in TAG and C-reactive protein levels of insulin-resistant subjects

Previous studies have shown that fish protein, as well as marine n-3 PUFA, may have beneficial effects on cardiovascular risk profile. The objectives of this study were to investigate the combined effects of fish gelatine (FG) and n-3 PUFA supplementation on (1) energy intake and body weight, (2) lipid profile and (3) inflammatory and CVD markers in free-living insulin-resistant males and females. Subjects were asked to consume, in a crossover study design with two experimental periods of 8 weeks each, an n-3 PUFA supplement and n-3 PUFA supplement plus FG (n-3 PUFA + FG). n-3 PUFA + FG led to an increase in protein intake and a decrease in carbohydrate intake compared with n-3 PUFA (P < 0·02) in males and females. Sex–treatment interactions were observed for TAG (P = 0·03) and highly sensitive C-reactive protein (hsCRP) (P = 0·001) levels. In females, n-3 PUFA reduced plasma TAG by 8 % and n-3 PUFA + FG by 23 %, whereas in males, n-3 PUFA reduced plasma TAG by 25 % and n-3 PUFA + FG by 11 %. n-3 PUFA increased serum hsCRP by 13 % and n-3 PUFA + FG strongly reduced hsCRP by 40 % in males, whereas in females, n-3 PUFA reduced serum hsCRP by 6 % and n-3 PUFA + FG increased hsCRP by 20 %. In conclusion, supplementation with FG may enhance the lipid-lowering effect of marine n-3 PUFA in females and beneficially counteract the effect of n-3 PUFA on serum hsCRP in males. Further studies are needed to identify the sex-dependent mechanisms responsible for the divergent effects of FG on TAG and hsCRP levels in females and males, respectively.

Diagnosis and treatment of sexual dysfunctions in late-onset hypogonadism

Testosterone is the principal androgen in the human male. The decline of testosterone with aging was recognized to be associated with a number of symptoms and signs that reduce the quality of life and that may even have severe, debilitating consequences. Clinically, late-onset hypogonadism (LOH) is diagnosed by use of biochemical and clinical measures. Despite published guidelines and recommendations, however, uncertainty surrounds the profile of clinical symptoms as well as the biochemical threshold of diagnosis. Clinicians should be aware of these shortcomings while adhering to the guidelines. Current treatment methods are centered on restoring testosterone to mid to lower levels of young men with natural testosterone replacements. Although recent studies have highlighted possible additional benefits involving improvement of systemic disorders, the goal of treatment is to improve sexual function, while observing for adverse effects in the prostate. Overall, the problem of LOH in debilitating the quality of life and well-being is real, and by following proper guidelines with attentiveness to the results of treatment trials, testosterone replacement therapy presents a safe and effective treatment option.

Sex hormone-binding globulin levels and metabolic syndrome and its features in adolescents

BACKGROUND

Low levels of sex hormone-binding globulin (SHBG) are associated with obesity, insulin resistance, and metabolic syndrome (MS) in men and women, and it has been suggested that SHBG could be a useful marker for MS risk.

OBJECTIVE

The aim of this study was to analyze the relationship of SHBG levels with MS and its components in Spanish adolescents.

METHODS

The sample population of this cross-sectional study was comprised of 386 male and 429 female adolescents, aged 12-16 yr. Anthropometric parameters and blood pressure (BP) were measured. Total cholesterol, high-density lipoprotein (HDL)-cholesterol, insulin, glucose, and SHBG levels were determined. The pediatric International Diabetes Federation (IDF) definition was used to classify adolescents for MS.

RESULTS

SHBG levels were lower in adolescents with MS or with some MS features. More than 90% of the abdominally obese adolescents were in the lowest and medium SHBG tertiles. In girls, BP was significantly higher in the lowest SHBG tertile than in the two others, whereas in boys BP levels were significantly higher in the lowest and medium tertiles than in the highest one. Insulin levels and homeostasis model assessment (HOMA) index were also significantly higher in the lowest SHBG tertile than in the two others.

CONCLUSIONS

The associations of SHBG with MS and its components, such as abdominal obesity, high BP or insulin levels, are already present in normal adolescents. This may suggest the possibility of using SHBG levels as a biomarker for MS risk in adolescents as well as adults.

Sex hormone-binding globulin: a new marker of disease severity and prognosis in men with chronic heart failure

INTRODUCTION AND OBJECTIVES

Sex hormone-binding globulin (SHBG) is a key regulator of the actions of anabolic steroids. Chronic heart failure (HF) has been associated with anabolic steroid deficiency, but its relationship with SHBG is not known.

METHODS

The study involved 104 men (53+/-11 years) with HF (i.e. left ventricular ejection fraction [LVEF] <40%) attending a specialist clinic on optimum treatment and in a stable condition. At enrolment, the median and interquartile range (IQR) SHBG level was determined, associated hormone levels were measured, and known risk factors were recorded. The study end-point was cardiac death within 3 years.

RESULTS

At enrolment, the SHBG level (median 34.5 nmol/L, IQR 27-50 nmol/L) was correlated with the N-terminal probrain natriuretic peptide level (r=0.271, P=.005), LVEF (r=-0.263, P=.007), body mass index (r=-0.199, P=.020) and total testosterone level (r=0.332, P=.001). The median SHBG level was higher in the 16 patients (15.4%) who died, at 48.5 nmol/L (IQR 36-69.5 nmol/L) vs. 33 nmol/L (IQR 25.3-48.7 nmol/L; P=.001), and a high level was associated with an increased risk of death (hazard ratio [HR]=1.045, 95% confidence interval [CI] 1.021-1.069; P< .001). The association remained significant after adjustment in Cox multivariate regression modeling, at HR=1.049 (95% CI 1.020-1.079; P=.001). Analysis by SHBG tertiles showed mortality was 30% in the third tertile, 14% in the second, and 4% in the first (log rank 0.007; HR=3.25, 95% CI 1.43-7.34; P=.004).

CONCLUSIONS

The SHBG level correlated with measures of HF severity and was associated with a higher risk of cardiac death. Further studies are needed to clarify whether SHBG plays a role in HF pathophysiology.

Prospective study of endogenous circulating estradiol and risk of stroke in older women

OBJECTIVE

To test the hypothesis that circulating endogenous estradiol is associated with stroke risk in older postmenopausal women. Stroke incidence increases after menopause, when endogenous estrogen levels fall, yet exogenous estrogen increases strokes in older postmenopausal women. The relation between endogenous estrogen and stroke is unclear.

DESIGN

Prospective case-control study.

SETTING

Study of Osteoporotic Fractures.

PATIENTS OR OTHER PARTICIPANTS

Women at least age 65 years (99% follow-up) who were not taking estrogen at baseline.

MAIN OUTCOME MEASURES

Free estradiol index (FEI) was calculated by dividing total estradiol by sex hormone-binding globulin concentrations measured in banked baseline serum. Using logistic regression, odds ratios were estimated for a first-ever atherothrombotic stroke associated with endogenous FEI in 196 women who had a subsequent validated stroke (median follow-up, 8 years) compared with 219 randomly selected women who did not. Potential mediators were assessed in multivariable models.

RESULTS

The age-adjusted odds of atherothrombotic stroke increased with increasing FEI quartiles (P(trend) = .007). Women in the highest FEI quartile had an age-adjusted 2.31-fold (odds ratio, 2.31; 95% confidence interval, 1.28-4.17) higher odds than women in the lowest quartile. Women with greater central adiposity had a suggestively stronger association (P = .08). Atherogenic dyslipidemia, type 2 diabetes mellitus, and C-reactive protein level were potential mediators of this relation.

CONCLUSIONS

Endogenous estradiol level is an indicator of stroke risk in older postmenopausal women, especially in those with greater central adiposity. Potential mediators, including atherogenic dyslipidemia, insulin resistance, and inflammation, might underlie this association. Whether estradiol, independent of atherogenic adiposity, influences such mediators and stroke risk needs to be determined. Estrogen-altering agents might be harmful or beneficial depending on endogenous estradiol levels, especially in women with greater central adiposity.

Sex hormone-binding globulin gene expression in the liver: drugs and the metabolic syndrome

Sex hormone-binding globulin (SHBG) is the main transport binding protein for sex steroid hormones in plasma and regulates their accessibility to target cells. Plasma SHBG is secreted by the liver under the control of hormones and nutritional factors. In the human hepatoma cell line (HepG2), thyroid and estrogenic hormones, and a variety of drugs including the antioestrogen tamoxifen, the phytoestrogen, genistein and mitotane (Op'DDD) increase SHBG production and SHBG gene promoter activity. In contrast, monosaccharides (glucose or fructose) effectively decrease SHBG expression by inducing lipogenesis, which reduces hepatic HNF-4alpha levels, a transcription factor that play a critical role in controlling the SHBG promoter. Interestingly, diminishing hepatic lipogenesis and free fatty acid liver biosynthesis also appear to be associated with the positive effects of thyroid hormones and PPARgamma antagonists on SHBG expression. This mechanism provides a biological explanation for why SHBG is a sensitive biomarker of insulin resistance and the metabolic syndrome, and why low plasma SHBG levels are a risk factor for developing hyperglycemia and type 2 diabetes, especially in women. These important advances in our knowledge of the regulation of SHBG expression in the liver open new approaches for identifying and preventing metabolic disorder-associated diseases early in life.

Sex hormone-binding globulin and lipid profile in pubertal children

Men and women have different lipid profiles throughout life, related to changes in sex hormones; and this has been associated with sex-related differences in the prevalence of coronary heart disease. The influence of sex hormone changes during puberty on the lipid profile has been reported, but levels of sex hormone-binding globulin (SHBG) (the specific plasma binding protein of sex hormones) have not been evaluated even though its regulatory role might be crucial. The aim of this study was to analyze the relationship between sex hormones and SHBG and changes in plasma lipid levels during puberty. Our population-based sample included 370 healthy schoolchildren (175 male and 195 female), ranging from 12 to 15 years old. High-density lipoprotein cholesterol (HDL-C) levels were significantly lower in 15-year-olds than in younger boys, and apolipoprotein (apo) A-I levels steeply decreased across the studied age groups. Parallel to these changes, testosterone levels increased whereas SHBG decreased as age increases in boys. In girls, no significant differences were observed in these variables among the age groups. Testosterone and SHBG were highly correlated with anthropometric variables. Sex hormone-binding globulin was negatively associated with triglycerides (TG) in both sexes, remaining statistically significant after further adjustment for age and body mass index (BMI) in girls. Sex hormone-binding globulin was the only predictive variable for HDL-C and TG in multiple linear regression analysis, after adjustment by BMI, in both sexes, accounting for 10% of the variance of HDL-C in boys and for around 5% of the variance of TG in both sexes. In boys, testosterone and SHBG remained significantly correlated to apo A-I levels, even after adjusting for age and BMI, and were the most important predictive variables for apo A-I in multiple linear regression analysis. In conclusion, SHBG levels are related to a decrease in HDL-C and apo A-I levels during puberty in boys and to a decrease in TG levels during puberty in both sexes.

Relative androgen excess during the menopausal transition predicts incident metabolic syndrome in midlife women: study of Women's Health Across the Nation

OBJECTIVE

During the menopausal transition, total testosterone (T) remains unchanged, whereas estrogen decreases markedly, creating a state of relative androgen excess. We hypothesized that change in the T-to-estradiol (T/E2) ratio during the menopausal transition would be associated with incident metabolic syndrome.

METHODS

The association between incident metabolic syndrome and total E2, total T, sex hormone-binding globulin, the free androgen index, baseline total T/E2 ratio, and the change of this ratio over time was evaluated in a multiethnic cohort of 1,862 premenopausal and perimenopausal women without diabetes enrolled in the Study of Women's Health Across the Nation.

RESULTS

New cases (n = 257) of metabolic syndrome were identified in the cohort during 6,296 woman-years of follow-up. The age-adjusted total T/E2 ratio increased by 10.1% per year during the 5 years of follow-up. Neither baseline nor change in E2 was associated with incident metabolic syndrome. Low sex hormone-biding globulin, free androgen index, and high total T at baseline all increased the risk of metabolic syndrome, but their change over time did not. Both baseline total T/E2 ratio (1.41; 95% CI = 1.17-1.69; P < 0.001) and its rate of change (1.24; 95% CI = 1.01-1.52; P < 0.04) were associated with increased incident metabolic syndrome independent of ethnicity.

CONCLUSIONS

The interaction between T and E2 during the menopausal transition, rather than the individual change of each over time, is a factor in the determination of risk of developing metabolic syndrome during the menopausal transition. This relationship was independent of ethnicity and other factors associated with prevalent metabolic syndrome before the onset of the menopausal transition.

SHBG levels correlate with insulin resistance in postmenopausal women

BACKGROUND

Overweight or central obesity is generally associated with increases in fasting insulin levels, insulin resistance, and glucose intolerance and has been identified as a target for new therapeutic strategies, including early change in lifestyle. Early biochemical markers for identifying at-risk patients will be useful for prevention studies. The aim of this study is to investigate whether or not SHBG level is a useful index of hyperinsulinemia and/or insulin resistance in pre- and postmenopausal obese women. At the same time, the relationship between SHBG concentrations and features of the metabolic syndrome were evaluated.

METHODS

229 women were eligible for this study. MetS was defined by using a modification of the ATP III guidelines. All patients were euthyroid, obese and overweight, 25 to 69 years of age. Subjects were divided into groups of premenopausal women (n=125) and postmenopausal women (n=104). Various fatness and fat distribution parameters, SHBG, sex hormones, FSH, LH, thyroid hormones, serum levels of fasting and postprandial glucose, lipid profile, uric acid and serum insulin, and blood pressure were measured.

RESULTS

No significant difference was found in mean SHBG levels between pre- and postmenopausal obese women in this study (p=0.866). In premenopausal obese women, SHBG correlated negatively with BMI, waist circumference, fasting glucose, uric acid levels and FAI. In postmenopausal obese women, SHBG correlated negatively with fasting glucose, postprandial plasma glucose, fasting insulin, HOMA-IR and FAI and positively with HDL. SHBG had a significant inverse association with MetS parameters only in postmenopausal women, also after adjusting for BMI, age and estradiol.

CONCLUSIONS

Obesity may influence the levels of endogenous sex steroid, especially after menopause. SHBG concentrations are correlated with features of the metabolic syndrome, particularly in postmenopausal obese women. These results suggest that SHBG may be an index of insulin resistance in postmenopausal obese women.

Androgens in relationship to cardiovascular risk factors in the menopausal transition

OBJECTIVE

To establish the relationship between androgens and cardiovascular disease (CVD) risk factors in the menopausal transition.

METHODS

A total of 124 women were divided into four groups: 29 premenopausal (PreM), 35 women in the menopausal transition still menstruating (MTM), 29 women in the menopausal transition with 3-6 months amenorrhea (MTA), and 31 postmenopausal women (PostM). Levels of triglycerides, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, glucose and insulin were assayed in all samples and waist circumference was measured. In a subgroup of 83 women (19 PreM, 21 MTM, 28 MTA and 15 PostM), levels of total testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS) and estradiol were determined. The free androgen index, Homeostasis Model Assessment (HOMA) index, Quantitative Insulin Sensitivity Check Index (QUICKI) and McAuley index, estradiol/total testosterone and triglyceride/HDL cholesterol ratios were calculated.

RESULTS

Androstenedione was higher in MTA vs. PostM women (p < 0.05); DHEAS was higher in PreM women vs. the other three groups (p < 0.05). Sex hormone binding globulin (SHBG) in MTM women was higher than in MTA women (p < 0.05); the free androgen index was lower in MTM women than in MTA and PostM women. SHBG and the free androgen index showed negative and positive correlations, respectively with waist circumference, insulin resistance and lipids. In a multiple regression analysis, considering waist circumference, neither free androgen index nor SHBG showed significant differences between groups. The waist circumference correlated only with SHBG (p = 0.022) and correlations between SHBG and insulin resistance markers continued to be significant, but relationships between SHBG and lipoproteins and all correlations found with free androgen index were lost.

CONCLUSIONS

An increment in the androgenic milieu that correlates with abdominal fat, insulin resistance and atherogenic lipoproteins becomes evident after the menopausal transition and suggests that evaluation of cardiovascular disease risk in these women should include androgens, considering that abdominal obesity is one of the main determinants of the relationship between androgenic parameters and cardiovascular risk factors.

The importance of the (TAAAA)n alleles at the SHBG gene promoter for the severity of coronary artery disease in postmenopausal women

OBJECTIVE

Androgen may be detrimental in the development of coronary artery disease (CAD) in women. We investigated possible associations between the (TAAAA)n polymorphism of sex hormone-binding globulin (SHBG) gene promoter, which influences transcriptional efficiency of the SHBG gene and the severity of CAD in women.

DESIGN

In this prospective clinical study, 146 postmenopausal women (46-88 y) undergoing coronary angiography were studied. CAD severity, history of angina and myocardial infarction, and reproductive history were recorded and hormonal parameters measured. According to the number of SHBG gene promoter repeat polymorphisms, participants were classified into short (seven or fewer), medium length (eight), and long repeat (nine or more) allele groups.

RESULTS

Significant CAD was more prevalent in the long repeat allele carrier group: 65% of the participants with three vessels with severe stenosis belonged to the long repeat allele group, whereas only 37% of participants with mild CAD belonged to this group (P=0.01). A history of angina and prevalence of hyperlipidemia was more frequent in the long repeat allele group (P<0.05). Calculated free testosterone levels were higher in the long repeat allele groups (P<0.05), whereas SHBG levels tended to be lower (P=0.06). SHBG levels correlated inversely with body mass index and waist circumference (P<0.05).

CONCLUSIONS

Longer (TAAAA)n repeats in the SHBG gene promoter are associated with more severe CAD in women undergoing coronary angiography, a finding not previously reported. This association may reflect the lifelong tissue exposure to higher free androgens and supports the adverse cardiovascular effect of androgenic exposure in this highly selected group of women.

Effects of testosterone undecanoate administered alone or in combination with letrozole or dutasteride in female to male transsexuals

INTRODUCTION

Testosterone undecanoate (TU) has potential as androgen therapy for ovariectomized female to male (FtM) transsexual subjects; however, the long-term physiologic effects of TU treatment, the significance of testosterone (T), and the T metabolites dihydrotestosterone (DHT) and estradiol (E) on specific outcome parameters are currently unknown.

AIM

The aim of this study was to investigate the long-term treatment of TU with regard to bone metabolism, body composition, and lipid profile in FtM subjects, and to evaluate the relationship between observed effects and circulating levels of T, E, and DHT.

MAIN OUTCOME MEASURES

Circulating follicle-stimulating hormone, luteinizing hormone, T, E, DHT, and lipid concentrations were measured, as well as bone metabolism, body composition, and insulin resistance.

METHODS

This was a 1-year, randomized treatment, open-label, uncontrolled safety study. Fifteen ovariectomized FtM subjects from an outpatient clinic were divided into three groups to receive TU 1,000 mg alone or in combination with oral administration of letrozole (L) 2.5 mg/die or dutasteride (D) 0.5 mg/die for a period of 54 weeks.

RESULTS

TU alone and TU + D treatments were successful in terms of hormone adjustment, did not result in any adverse effects, and were well-tolerated. Bone mineral density decreased by an average of 0.9 g/cm(2) in the TU + L group, and the addition of D resulted in a failure to gain lean mass.

CONCLUSIONS

This study confirmed that TU is a successful and safe treatment for FtM subjects. These data indicate that E has an important role in bone metabolism and that DHT may play a role in muscle metabolism.

Subclinical impairment of left ventricular function in young obese women: contributions of polycystic ovary disease and insulin resistance

CONTEXT

Obesity and insulin resistance (IR) may produce disturbances of left ventricular (LV) function. Obese women with polycystic ovary syndrome (PCO), characterized by hormonal and metabolic abnormalities, are thought to be at particularly increased cardiovascular risk.

OBJECTIVES

We sought to determine the influence of IR on LV function in obese young women with and without PCO and without other comorbidities.

DESIGN

This was a cross-sectional study.

SETTING

The study was performed at a university hospital.

PATIENTS

A total of 150 women aged younger than 40 yr with a body mass index (BMI) of 30 kg/m(2) or more was classified into three groups: with both PCO and IR, without PCO and with IR, and without either PCO or IR.

MAIN OUTCOME MEASURES

Tissue Doppler-derived myocardial velocities, strain-rate and strain, and metabolic and hormonal measurements were calculated.

RESULTS

Subclinical impairment of LV systolic and diastolic function as indicated by lower peak strain (P < 0.001), peak systolic strain rate (P < 0.001), peak early diastolic strain rate (P < 0.001), and peak early diastolic velocity (P < 0.01) was demonstrated in both groups with IR. IR subjects with and without PCO did not differ in any LV function indices. Strain was independently associated with fasting insulin (beta = -0.39; P < 0.001), urinary albumin excretion (UAE) (beta = -0.36; P < 0.001), and BMI (beta = -0.22; P < 0.03), and peak early diastolic strain rate was associated with UAE (beta = -0.35; P < 0.001), fasting insulin (beta = -0.24; P < 0.02), BMI (beta = -0.23; P < 0.02), and SHBG (beta = 0.20; P < 0.04).

CONCLUSIONS

In obese young women, fasting insulin, BMI, SHBG, and UAE are independent correlates of impaired LV performance. The contribution of PCO to LV function abnormalities is linked to IR, but not to other hormonal aberrations associated with this condition.

Menopause and the metabolic syndrome: the Study of Women's Health Across the Nation

BACKGROUND

Cross-sectional studies suggest that prevalence of the metabolic syndrome (MetS) increases from premenopause to postmenopause in women, independent of age. Little is known about why. We hypothesized that the incidence of the MetS increases with progression through menopause and that this increase is explained by the progressive androgenicity of the hormonal milieu.

METHODS

This longitudinal, 9-year study of 949 participants in the Study of Women's Health Across the Nation investigates the natural history of the menopausal transition. Participants of 5 ethnicities at 7 geographic sites were recruited when they were premenopausal or early perimenopausal and were eligible for this study if they (1) reached menopause during the study; (2) had never taken hormone therapy, and (3) did not have diabetes mellitus or the MetS at baseline. The primary outcome was the presence of MetS using National Cholesterol Education Program Adult Treatment Panel III criteria. Secondary outcomes were the components of the MetS.

RESULTS

By the final menstrual period, 13.7% of the women had new-onset MetS. Longitudinal analyses, centered at the final menstrual period, were adjusted for age at menopause, ethnicity, study site, marital status, education, body mass index, smoking, and aging. Odds of developing the MetS per year in perimenopause were 1.45 (95% confidence interval, 1.35-1.56); after menopause, 1.24 (95% confidence interval, 1.18-1.30). These odds were significantly different (P < .001). An increase in bioavailable testosterone or a decrease in sex hormone-binding globulin levels increased the odds.

CONCLUSIONS

As testosterone progressively dominates the hormonal milieu during the menopausal transition, the prevalence of MetS increases, independent of aging and other important covariates. This may be a pathway by which cardiovascular disease increases during menopause.

Sex hormones, sex hormone binding globulin, and abdominal aortic calcification in women and men in the multi-ethnic study of atherosclerosis (MESA)

BACKGROUND

Conflicting findings exist regarding the associations of sex hormones with subclinical atherosclerosis.

METHODS

This is a substudy from MESA of 881 postmenopausal women and 978 men who had both abdominal aortic calcification (AAC) quantified by computed tomography and sex hormone levels assessed [Testosterone (T), estradiol (E2), dehydroepiandrosterone (DHEA), and sex hormone binding globulin (SHBG)]. We examined the association of sex hormones with presence and extent of AAC.

RESULTS

For women, SHBG was inversely associated with both AAC presence [OR=0.62, 95% CI 0.42-0.91 for 1 unit greater log(SHBG) level] and extent [0.29 lower log(AAC) for 1 unit greater log(SHBG) level, beta=-0.29 (95% CI -0.57 to -0.006)] adjusting for age, race, hypertension, smoking, diabetes, BMI, physical activity, and other sex hormones. After further adjustment for total and HDL-cholesterol, SHBG was not associated with ACC presence or extent. In men, there was no association between SHBG and AAC. In both men and women, neither T, E2, nor DHEA was associated with AAC presence or extent.

CONCLUSION

After adjustment for non-lipid cardiovascular risk factors, SHBG levels are inversely associated with both the presence and severity of AAC in women but not in men, which may be accounted for by HDL.

Effect of insulin sensitivity on SHBG levels in premenopausal versus postmenopausal obese women

This study was performed to evaluate the impact of insulin sensitivity on sex hormone-binding globulin (SHBG) and sex steroids in premenopausal and postmenopausal euthyroid obese women. A total of 227 women were eligible for this study. All were euthyroid, obese, and overweight; ages ranged from 25 to 69 years. Women were divided into premenopausal (n=151) and postmenopausal (n=76) groups. SHBG, sex steroids, thyrotropin, fasting and postprandial glucose, lipid profile, uric acid, serum insulin, and blood pressure were measured. No significant difference was found in mean SHBG levels between premenopausal and postmenopausal women. The investigators observed that during transition from premenopause to postmenopause, SHBG levels increased in insulin-sensitive women in the postmenopausal group; however, SHBG levels decreased in insulinresistant women. It was concluded that SHBG blood concentration factors are likely to change during transition from premenopause to postmenopause. The positive effect of estradiol on SHBG levels is probably stronger in premenopausal women than in postmenopausal women. It has been noted that after menopause, the impact of insulin resistance on SHBG level seems more important than the effect of estradiol.

Metabolism of low-dose inorganic arsenic in a central European population: influence of sex and genetic polymorphisms

BACKGROUND

There is a wide variation in susceptibility to health effects of arsenic, which, in part, may be due to differences in arsenic metabolism. Arsenic is metabolized by reduction and methylation reactions, catalyzed by reductases and methyltransferases.

OBJECTIVES

Our goal in this study was to elucidate the influence of various demographic and genetic factors on the metabolism of arsenic.

METHODS

We studied 415 individuals from Hungary, Romania, and Slovakia by measuring arsenic metabolites in urine using liquid chromatography with hydride generation and inductively coupled plasma mass spectrometry (HPLC-HG-ICPMS). We performed genotyping of arsenic (+III) methyltransferase (AS3MT), glutathione S-transferase omega 1 (GSTO1), and methylene-tetrahydrofolate reductase (MTHFR).

RESULTS

The results show that the M287T (T-->C) polymorphism in the AS3MT gene, the A222V (C-->T) polymorphism in the MTHFR gene, body mass index, and sex are major factors that influence arsenic metabolism in this population, with a median of 8.0 microg/L arsenic in urine. Females < 60 years of age had, in general, higher methylation efficiency than males, indicating an influence of sex steroids. That might also explain the observed better methylation in overweight or obese women, compared with normal weight men. The influence of the M287T (T-->C) polymorphism in the AS3MT gene on the methylation capacity was much more pronounced in men than in women.

CONCLUSIONS

The factors investigated explained almost 20% of the variation seen in the metabolism of arsenic among men and only around 4% of the variation among women. The rest of the variation is probably explained by other methyltransferases backing up the methylation of arsenic.

Role of D327N sex hormone-binding globulin gene polymorphism in the pathogenesis of polycystic ovary syndrome

SHBG (sex hormone-binding globulin) is a transport protein specific for dihydrotestosterone, testosterone and estradiol. The missense mutation in exon 8 (GAC-->AAC) causing the amino acid exchange Asp-->Asn in codon 327 (D327N) correlates according to the published data with increased SHBG levels. We studied possible association of this polymorphism with polycystic ovary syndrome (PCOS) and anthropometric and biochemical parameters in 248 PCOS patients and 109 healthy control women. The D327N polymorphism (wild-type and variant allele) was detected using PCR-RFLP method (restriction enzyme Bbs-I). For statistical evaluation chi(2) test, Mann-Whitney test, ANCOVA, ANOVA (NCSS 2004, Statgraphics Plus v.5.1, USA) were used. There was no significant difference in genotype distribution between PCOS and controls (chi(2)=1.03, p=0.59). Moreover, we did not find an association of the variant allele with plasma SHBG level, steroid hormones, or screened parameters of lipid and glucose metabolism. In conclusion, the D327N polymorphism of the SHBG gene does not influence susceptibility to PCOS.

Association between hormones and metabolic syndrome in older Italian men

OBJECTIVES

To determine whether low levels of testosterone, sex hormone binding globulin (SHBG), insulin-like growth factor-1 (IGF-1), and dehydroepiandrosterone sulfate (DHEAS) and high levels of cortisol and leptin would be associated with metabolic syndrome (MS).

DESIGN

Cross-sectional.

SETTING

Population-based sample of older Italian men.

PARTICIPANTS

Four hundred fifty-two men aged 65 and older enrolled in the Invecchiare in Chianti (InCHIANTI) study.

MEASUREMENTS

Complete data on testosterone, cortisol, DHEAS, SHBG, fasting insulin, IGF-1 and leptin. MS was defined according to Adult Treatment Panel III criteria.

RESULTS

MS was present in 73 men (15.8% of the sample). After adjusting for confounders, total testosterone (P < .05) and log (SHBG) (P < .001) were inversely associated, whereas log (leptin) was positively associated with MS (P < .001). Independent of age, log (SHBG) was positively associated with high-density lipoprotein cholesterol (P < .05) and negatively associated with abdominal obesity (P < .001) and triglycerides (P < .001). Log (leptin) was significantly associated with each component of MS. Cortisol, DHEAS, free and bioavailable testosterone, and IGF-1 were not associated with MS. Having three or more hormones in the lower (for hormones lower in MS) or the upper (for hormones higher in MS) quartile was associated with three times the risk of being affected by MS (odds ratio = 2.8, 95% confidence interval = 1.3-6.9) (P = .005), compared with not having this condition.

CONCLUSION

Total testosterone and SHBG are negatively and leptin is positively associated with MS in older men. Whether specific patterns of hormonal dysregulation predict the development of MS should be tested in longitudinal studies.

Association of hormonal dysregulation with metabolic syndrome in older women: data from the InCHIANTI study

Metabolic syndrome (MetS) is a strong risk factor for type 2 diabetes and cardiovascular disease. Conditions associated with hyperandrogenism are often associated with glucose intolerance and other features of MetS in young women. As the prevalence of MetS increases with age and is probably multifactorial, it is reasonable to hypothesize that age-related changes in androgens and other hormones might contribute to the development of MetS in older persons. However, this hypothesis has never been tested in older women. We hypothesized that high levels of testosterone, dehydroepiandrosterone sulfate (DHEA-S), and cortisol and low levels of sex hormone-binding globulin (SHBG) and IGF-I would be associated with MetS in a representative cohort of older Italian women independently of confounders (including inflammatory markers). After exclusion of participants on hormone replacement therapy and those with a history of bilateral oophorectomy, 512 women (>/=65 yr) had complete data on testosterone, cortisol, DHEA-S, SHBG, fasting insulin, total and free IGF-I, IL-6, and C-reactive protein (CRP). MetS was defined according to ATP-III criteria. Insulin resistance was calculated according to HOMA. MetS was found in 145 women (28.3%). Participants with vs. those without MetS had higher age-adjusted levels of bioavailable testosterone (P < 0.001), IL-6 (P < 0.001), CRP (P < 0.001), and HOMA (P < 0.001) and lower levels of SHBG (P < 0.001). After adjustment for potential confounders, participants with decreased SHBG had an increased risk of MetS (P < 0.0001) vs. those with low SHBG. In a further model including all hormones and confounders, log SHBG was the only independent factor associated with MetS (OR: 0.44, 95% CI 0.21-0.91, P = 0.027). In older women, SHBG is negatively associated with MetS independently of confounders, including inflammatory markers and insulin resistance. Further studies are needed to support the notion that raising SHBG is a potential therapeutic target for prevention and treatment of MetS.

Low sex hormone-binding globulin is associated with the metabolic syndrome in postmenopausal women

Although an association between the metabolic syndrome and hyperandrogenism has been suggested in women with polycystic ovarian syndrome, few studies have investigated this relationship in postmenopausal women. We measured estradiol, testosterone, and sex hormone-binding globulin (SHBG) and calculated the free androgen index (FAI) in 212 postmenopausal women not using hormone therapy in the Women's Health Study. A modified definition of the metabolic syndrome (3 or more of the following: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein, elevated blood pressure, and abnormal glucose metabolism) from the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults was used. Women with the metabolic syndrome had higher mean levels of estradiol, testosterone, and FAI values and lower SHBG levels. Higher FAI and lower SHBG were associated with all components of the metabolic syndrome. After adjustment for BMI and other factors, women in the highest tertile of FAI had an odds ratio of 12.6 (95% confidence interval, 3.8-41.6) for the metabolic syndrome, whereas those in the lowest SHBG tertile had an odds ratio of 7.3 (95% confidence interval, 2.7-19.8). When stratified by body mass index, the associations with high FAI and low SHBG remained significant even in women with body mass index less than 26.7 kg/m2. An androgenic hormone profile is associated with both the individual components of the metabolic syndrome and clustering of metabolic abnormalities in postmenopausal women.