SHBG levels correlate with insulin resistance in postmenopausal women

Questioning PCOS phenotypes for reclassification and tailored therapy

Precise diagnoses are essential for defining appropriate treatments. This is particularly true for polycystic ovary syndrome (PCOS), whose phenotypical manifestations have recently suggested a possible diversity of etiological factors. PCOS is defined on the basis of gynecological and endocrinological alterations, but the patients often display considerable metabolic impairments, such as insulin resistance, that may worsen typical symptoms. The Rotterdam criteria fail to address this aspect, and the medical community has recently started to consider them as misleading diagnostic tools, casting doubts on whether the term PCOS is suited to describe all the clinical manifestations observed. This Opinion collects and critically discusses the scientific reports that question the definition of PCOS, calling for a revision of the current diagnostic criteria.

A cross-sectional study of the association between circulating sex hormone-binding globulin levels and selected adipokines in women with polycystic ovary syndrome

INTRODUCTION

Changes in the proportion of pro-inflammatory and anti-inflammatory adipokines may reflect the accumulation of lipids in the liver and the development of insulin resistance. Both liver steatosis and insulin resistance result in decreased sex hormone-binding globulin (SHBG) synthesis. This study aimed to analyze associations between circulating SHBG and adipokines levels in women with polycystic ovary syndrome (PCOS).

MATERIAL AND METHODS

A cross-sectional cohort study involved 87 women with phenotype A of PCOS (39 normal weight and 48 obese). Body mass, height, and waist circumference were measured, and BMI was calculated. In addition, body composition was assessed using the bioimpedance method. Serum SHBG levels and plasma apelin-36 and apelin-12, adiponectin, leptin, omentin-1, and RBP-4 were determined by using the ELISA method. The participants were divided into subgroups with SHBG concentrations above and below this lower limit [N = 35 (40.2%) and N = 52 (59.8%), respectively].

RESULTS

The median adiponectin, apelin-12, and apelin-36 levels were significantly lower, and leptin levels were significantly higher in the subgroup with low SHBG levels than that in the subgroup above the lower limit of the reference range, while there were no differences in median omentin-1 and RBP-4 between the study subgroups. There were positive correlations between SHBG and omentin-1, adiponectin, apelin-36, and apelin-12 levels, as well as negative correlation with leptin levels. However, after adjustment by BMI, waist circumference, and body fat percentage, only the association between SHBG and omentin-1 remained significant.

CONCLUSION

Our results show associations between circulating SHBG and adipokine levels in women with PCOS and support the role of hormonal dysfunction of the adipose tissue in the pathogenesis of PCOS.

The cut-off value for HOMA-IR discriminating the insulin resistance based on the SHBG level in women with polycystic ovary syndrome

Introduction

The study aimed to estimate the cut-off value for homeostatic model assessment for insulin resistance (HOMA-IR) discriminating the insulin resistance based on the sex hormones binding globulin (SHBG) level in women with polycystic ovary syndrome (PCOS).

Materials and methods

Data from medical records of 854 Caucasian women diagnosed with PCOS were analyzed. Anthropometric data, fasting plasma glucose, insulin and SHBG levels were measured. HOMA-IR was calculated with a standard formula. The cut-off value was calculated using receiver-operating characteristics.

Results

Circulating SHBG levels below the normal range (26.1 nmol/L) were found in 25.4% of study participants. This subgroup had a significantly higher BMI, fasting glucose and insulin concentrations and HOMA-IR values. Empirical optimal cut-off values for HOMA-IR corresponding to low SHBG levels was ≥2.1 [area under the curve (AUC) 0.73, accuracy 0.65, sensitivity 72.3%, specificity 63.1%, positive predictive value (PPV) 40.0%, negative predictive value (NPV) 87.0%].

Conclusions

Our study suggests that the cut-off point for HOMA-IR discriminating the insulin resistance based on the SHBG level, in young Caucasian women with polycystic ovary syndrome is 2.1, and is consistent with the cut-off value adopted by the European Group for the Study of Insulin Resistance (above 2.0).

Prediction of Insulin Resistance and Impaired Fasting Glucose Based on Sex Hormone-Binding Globulin (SHBG) Levels in Polycystic Ovary Syndrome

OBJECTIVE

Decreased synthesis of sex hormone-binding globulin (SHBG) related to hyperinsulinemia is one of the disturbances characteristic of polycystic ovary syndrome (PCOS). Hyperinsulinemia is a compensatory mechanism for liver insulin resistance (IR); thus, SHBG may be considered as a surrogate marker of liver IR. Therefore, this study aimed to assess the prediction of IR and impaired fasting glucose (IFG) based on SHBG levels in women with PCOS.

METHODS

This analysis included data retrieved from medical records of 854 patients with PCOS hospitalized in the Gynecological Endocrinology Clinic from 2012 to 2019. Data including anthropometric parameters, fasting plasma glucose, insulin, and SHBG levels were analyzed. BMI and HOMA-IR were calculated with standard formulas.

RESULTS

IFG and IR assessed based on HOMA-IR values > 2.0 were found in 19.5% and 47.8% of the study group, respectively. Empirical optimal cutoff values for SHBG levels were ≤41.5 nmol/L typical for IR (AUC 0.711, sensitivity 61.1%, specificity 71.6%, positive predictive value (PPV) 70.7%, and negative predictive value (NPV) 62.1%). The probability of insulin resistance occurrence for SHBG concentration 26.1 nmol/L (the lower normal range) was 61.6% (95% CI: 57.4%-65.8%). The SHBG concentration of 36.4 nmol/L and 8.1 nmol/L was related to a 10% and 20% probability of IFG, respectively.

CONCLUSION

In conclusion, this is the first study estimating the probability of liver IR and IFG occurrence based on SHBG levels in women with PCOS. Despite the low sensitivity, SHBG level below 42 nmol/L should cause closer monitoring for the fatty liver and prediabetes.

An Investigation on the Risk Factors of Thyroid Diseases in Community Population in Hainan

BACKGROUND

In recent years, the incidence of thyroid diseases has increased significantly, which has seriously affected people's work and life. The purpose of this study was to explore the epidemiological characteristics of thyroid diseases and autoantibodies.

METHOD

According to the principle of overall sampling, resident residents ≥18 years and who will not move within 5 years are randomly selected. A total of 2136 eligible individuals were divided into case and control groups according to whether they have thyroid disease. Finally, the impact of potential risk factors on thyroid diseases was evaluated.

RESULTS

The overall prevalence of thyroid disease was 58.3%, and there was a significant difference in the prevalence of thyroid disease between women and men (p = 0.004). Except for the age group ≥70 years, with the increase in age, the prevalence gradually increased (p < 0.05). Participants with positive thyroid autoantibodies (TPOAb or TgAb) had a higher prevalence than participants with negative autoantibodies. The positive rate of autoantibodies in women was higher than that in men (p < 0.05). UIC (p = 0.004) and free thyroid hormone (FT4) (p = 0.001) levels of men were higher than those of women, and the TSH level of women was higher than that of men (p = 0.002). The regression analysis showed that women, older age, and family history of thyroid disease were independent risk factors for thyroid disease.

CONCLUSION

The prevalence of thyroid diseases in Hainan was high. Women are more susceptible to thyroid disease than men, and the prevalence increased with age.

Evaluation of the Efficacy of Sex Hormone-Binding Globulin in Insulin Resistance Assessment Based on HOMA-IR in Patients with PCOS

This study aimed to evaluate the efficacy of SHBG in predicting insulin resistance (IR) in newly diagnosed, untreated patients with polycystic ovary syndrome (PCOS). Hundred newly diagnosed, untreated patients with PCOS and 61 subjects without PCOS (41 healthy volunteers with normal BMI and 20 subjects with overweight/obese) were included in the study. Receiver-operating characteristic (ROC) analysis was used to assess the effectiveness of SHBG in predicting IR in overweight/obese and non-overweight PCOS patients and the optimal cut-off values of SHBG. The results showed negative correlations between log-SHBG and log-I₀ (r = - 0.372, P < 0.001) and log-SHBG and log-Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (r = - 0.393, P < 0.001) after adjusting for blood pressure, serum lipid, age, and body mass index (BMI) in all of the PCOS patients. In patients with IR (defined as HOMA-IR ≥2.29), the area under the ROC curves (AUCs) of the SHBG for ROC analysis in the non-overweight group, overweight/obese group, and all PCOS patients were 0.774 (P = 0.0001), 0.922 (P = 0.0001), and 0.885 (P = 0.0001), respectively. The optimal cut-off value of SHBG was 37 nmol/L with a sensitivity of 97.62% and specificity of 80.85% in the overweight group. In patients with IR (HOMA-IR ≥2.5), the AUCs of SHBG for ROC analysis in the non-overweight group, overweight/obese group, and all PCOS patients were 0.741 (P = 0.0003), 0.928 (P = 0.0001), and 0.880 (P = 0.0001), respectively. The optimal cut-off value of SHBG was 30.2 nmol/L with a sensitivity of 97.44% and specificity of 82.69% in the overweight/obese group. In conclusion, this study observed a negative correlation between SHBG and HOMA-IR in PCOS patients after adjustment of confounding factors. SHBG was an independent influential factor of HOMA-IR and can be used as a positive predictive marker for IR in PCOS patients, especially in those who are overweight/obese.

Whey Protein Supplementation Improves the Glycemic Response and May Reduce Non-Alcoholic Fatty Liver Disease Related Biomarkers in Women with Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) increases type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) with insulin resistance. We hypothesized that a 35 g whey preload would improve insulin sensitivity and glucose handling while reducing biomarkers associated with NAFLD. Twenty-nine age-matched women (CON = 15, PCOS = 14) completed oral glycemic tolerance tests following baseline (Day 0) as well as an acute (Day 1) and short-term whey supplementation (Day 7). Whey had an interaction effect on glucose (p = 0.02) and insulin (p = 0.03), with glucose remaining stable and insulin increasing with whey supplementation. Insulin sensitivity (p < 0.01) improved with whey associated with increased glucagon secretion (p < 0.01). Alanine aminotransferase (ALT), and aspartate aminotransferase (AST) remained unchanged, but “day” had an effect on the AST:ALT ratio (p = 0.04), whereas triglycerides and sex hormone binding globulin overall were greater in the PCOS group (p < 0.05). Total cholesterol decreased in PCOS (by 13%) and CON (by 8%) (NS). HepG2 cells treated with plasma from participants before and after whey decreased lipid accumulation in the PCOS group after whey (p < 0.05). Whey provided an insulinogenic and glycemic homeostatic effect in women with PCOS with the potential to combat NAFLD-consequences.

Laurus nobilis ethanolic extract attenuates hyperglycemia and hyperinsulinemia-induced insulin resistance in HepG2 cell line through the reduction of oxidative stress and improvement of mitochondrial biogenesis - Possible implication in pharmacotherapy

The aim of this study was to establish the potential effect of Laurus nobilis ethanolic extract on improving insulin sensitivity and protecting liver cells from apoptosis, mitochondrial dysfunction, oxidative stress (OS), and inflammation; all of which considered as major alterations occurring during insulin resistance (IR) as well as diabetes onset, in hyperinsulinemic and hyperglycemic-induced HepG2 cell line. Thereby, L. nobilis ethanolic extract has been first chemically characterized using LC-MS/MS technique. Subsequently, HepG2 cells were pre-treated with an optimal concentration of L. nobilis ethanolic extract for 24 h, and then, subjected to 30 mM D-glucose and 500 nM insulin mixture for another 24 h in order to induce hyperinsulinemia and hyperglycaemia (HI/HG) status. Several parameters such as biocompatibility, hepatotoxicity, reactive oxygen species (ROS), mitochondrial transmembrane potential, dynamics, and metabolism, multicaspase activity, glucose uptake, in addition to genes and proteins expression levels were investigated. The obtained results showed that the bioactive extract of Laurus nobilis increased the number of living cells and their proliferation rate, significantly attenuated apoptosis by modulating pro-apoptotic pathways (p21, p53 and Bax genes), allowed a relative normalization of caspases-activity, and decreased the expression of inflammatory markers including c-Jun, NF-κB and Tlr4 transcripts. L. Nobilis ethanolic extract reduced considerably total intracellular ROS levels in challenged HepG2 cells, and regulated the mitochondrial OXPHOS pathway, demonstrating the potential antioxidant effect of the plant. Ethanolic plant extract increased insulin sensitivity, since an elevated expression of master transcripts responsible for insulin sensitivity including IRS1, IRS2, INSR was found. Taken together, obtained data suggest that L. nobilis ethanolic extract offers new insights in the development of potential antioxidant, insulin sensitizing as well as hepatoprotective drugs.

Correlation Between Serum Uric Acid and Body Fat Distribution in Patients With Polycystic Ovary Syndrome

OBJECTIVE

This study aims to investigate the correlation between serum uric acid levels and body fat distribution in patients with polycystic ovary syndrome (PCOS).

METHODS

Between May 2017 and March 2021, a total of 199 patients with PCOS were recruited from the Department of Endocrinology and Metabolism at the Shanghai Tenth People's Hospital. Anthropometric characteristics, metabolic parameters, and reproductive hormones were measured. Hyperuricemia was defined as serum uric acid (SUA) greater than 420 μmol/l. Dual-energy X-ray absorptiometry (DEXA) was used to measure body fat distribution.

RESULTS

The prevalence of hyperuricemia in patients with PCOS was 28.64%. PCOS patients with hyperuricemia are more obese and have a higher waist-to-hip ratio (WHR) and worse lipid metabolism than those without hyperuricemia. According to SUA quartiles, patients in the highest quartile had higher total testosterone (TT), body fat accumulation, and lower sex hormone-binding globulin (SHBG) than patients in the lowest quartile. SUA was correlated with percentage of total body fat, arm fat mass, leg fat mass, trunk fat mass, android/gynoid (A/G) ratio, and visceral adipose tissue (VAT) mass. After controlling possible confounders, logistic regression analysis found that only excessive VAT mass could significantly increase the risk of hyperuricemia in patients with PCOS.

CONCLUSION

In patients with PCOS, a high level of VAT mass, but not other fat compartments, will exacerbate the risk of hyperuricemia. Attention should be paid to the role of excessive VAT in the occurrence and development of PCOS with hyperuricemia.

Circulating sex hormone binding globulin levels are modified with intensive lifestyle intervention, but their changes did not independently predict diabetes risk in the Diabetes Prevention Program

INTRODUCTION

Sex hormone binding globulin (SHBG) levels are reported to be inversely associated with diabetes risk. It is unknown whether diabetes prevention interventions increase SHBG and whether resultant changes in SHBG affect diabetes risk. The purpose of this analysis was to determine whether intensive lifestyle intervention (ILS) or metformin changed circulating SHBG and if resultant changes influenced diabetes risk in the Diabetes Prevention Program (DPP).

RESEARCH DESIGN AND METHODS

This is a secondary analysis from the DPP (1996-2001), a randomized trial of ILS or metformin versus placebo on diabetes risk over a mean follow-up of 3.2 years. The DPP was conducted across 27 academic study centers in the USA. Men, premenopausal and postmenopausal women without hormone use in the DPP were evaluated. The DPP included overweight/obese persons with elevated fasting glucose and impaired glucose tolerance. Main outcomes measures were changes in SHBG levels at 1 year and risk of diabetes over 3 years.

RESULTS

ILS resulted in significantly higher increases (postmenopausal women: p<0.01) or smaller decrements (men: p<0.05; premenopausal women: p<0.01) in SHBG compared with placebo or metformin. Changes in SHBG were primarily attributable to changes in adiposity. There were no consistent associations of change in SHBG with the risk of diabetes by treatment arm or participant group.

CONCLUSIONS

Lifestyle intervention may be associated with favorable changes in circulating SHBG, which is largely due to changes in adiposity. Changes in circulating SHBG do not independently predict reductions in diabetes incidence.

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.

Cardiometabolic Proteins Associated with Metabolic Syndrome

Background: Although metabolic syndrome (MetS) was described in the late 80s, the molecular mechanisms underlying clustering of risk factors in certain individuals are not fully understood. The present study used targeted proteomics to establish cardiometabolic proteins related to all MetS components, thereby providing new hypotheses regarding pathways involved in the pathogenesis of MetS. Methods: In the EpiHealth study, 249 cardiometabolic proteins were measured by proximity extension assay (PEA) and related to the five MetS components [consensus-modified National Cholesterol Education Program (NCEP) criteria] in 2,444 participants aged 45-75 years (50% women). Results: Thirty-one proteins were associated with systolic blood pressure following adjustment for age and sex (P < 0.000040, taking multiple testing into account). The corresponding number of proteins significantly associated with fasting glucose, waist circumference, high-density lipoprotein cholesterol, and serum triglycerides were 58, 132, 127, and 148. Twenty-two proteins were significantly related to all 5 MetS components, and of those, 20 were with MetS as a binary outcome (n = 600, 24% of the sample) following adjustment for age, sex, fat mass, and lifestyle factors (alcohol intake, smoking, education, and exercise habits). Conclusion: Using targeted proteomics, we identified 20 proteins reflecting a range of pathways, such as immunomodulation at different levels; regulation of adipocyte differentiation; lipid, carbohydrate, and amino acid metabolism; or insulin-like growth factor signaling, to be strongly associated with MetS independently of fat mass and lifestyle factors. Whether some of these proteins are causally involved in the pathogenesis of clustering of multiple risk factors in the same individual remains to be investigated.

Thigh and abdominal adipose tissue depot associations with testosterone levels in postmenopausal females

OBJECTIVE

Research findings on the relationship between serum androgens and adipose tissue in older females are inconsistent. We aimed to clarify the relationship using state-of-the-art techniques to evaluate associations between body fat distribution and plasma testosterone (T) levels in older postmenopausal women.

DESIGN

Observational, cross-sectional study of healthy, community dwelling postmenopausal women.

PATIENTS AND MEASUREMENTS

Postmenopausal women (60-80 years old) were included in this study. Overall body composition was evaluated by dual-energy X-ray absorptiometry. Abdominal and thigh fat depots were measured by magnetic resonance imaging. Circulating T concentrations were analysed by liquid chromatography-tandem mass spectrometry.

RESULTS

Thirty-five women (66.6 ± 0.8 years) participated in this study. T levels were positively associated with clinical proxy measures of adiposity including weight (ρ = 0.39), BMI (ρ = 0.43) and waist circumference (ρ = 0.39) (all P < 0.05). Fat mass and % body fat were correlated with T levels (ρ = 0.42 and 0.38 respectively, both P < 0.05). T correlated with overall and superficial abdominal fat (ρ = 0.34 and 0.37 respectively, both P < 0.05) but not with visceral adipose tissue. T increased with greater thigh fat (ρ = 0.49, P < 0.05) in both superficial and deep depots (ρ = 0.50 and 0.35 respectively, both P < 0.05).

CONCLUSION

Our results suggest that postmenopausal women with higher circulating T levels have both higher regional and overall body adiposity. These findings underscore the sexual dimorphism in the relationship between serum androgen levels and adiposity.

Association Between Thyroid Nodules and Volume and Metabolic Syndrome in an Iodine-Adequate Area: A Large Community-Based Population Study

Background: Given its high incidence, thyroid nodule (TN) warrants public attention. Thyroid volume (TV) has also been associated with multiple factors, such as iodine deficiency and supply and body mass index. It is well known that metabolic syndrome (MetS) comprises many metabolic disturbances, with insulin resistance being its major component. Materials and Methods: The aim of this study was to investigate the relationship between TN and TV and MetS and its components in an iodine-adequate area in Asia. All participants were asked to complete a questionnaire. After excluding 938 individuals based on the exclusion criteria, we reviewed data from 927 of 1865 participants. Adopting MetS diagnostic criteria, we found 437 subjects to be MetS positive [MetS(+)] and 490 subjects to be MetS negative [MetS(-)], respectively. Multivariate linear regression was used to assess the relationship between TNs and MetS. Moreover, univariate binary logistic regression analyses were used to calculate odds ratios (ORs), and 95% confidence intervals (CIs) were used to estimate the associations between different variables and TNs. Results: A total of 232 females and 205 males were MetS(+), as diagnosed using the International Diabetes Federation criteria. However, there were 330 females and 160 males in the group of MetS(-) individuals. The prevalence of TNs was 38.29% in the MetS(+) group and 17.79% in the MetS(-) group. After adjusting for systolic blood pressure, diastolic blood pressure, and gender, only high-density lipoprotein, waist circumference (WC), and age were related to TNs (OR = 0.45, 95% CI 0.27-0.75, P = 0.0023; OR = 1.04, 95% CI 1.02-1.06, P = 0.0036). The TV of all participants was 13.98 (11.24, 17.01) mL; 13.26 (10.62, 16.17) mL for females and 14.96 (11.83, 18.01) mL for males. It was found that only WC was related to TV, after controlling for sex and age (P = 0.02). Conclusions: The morbidity among TN patients in the MetS(+) group was higher than that among the MetS(-) group. High-density lipoprotein cholesterol emerged as a protective factor, and WC was a risk factor for TN. Moreover, TV was related to MetS, and WC was an independent risk factor for TV.

Investigation on the factors that influence the prevalence of thyroid nodules in adults in Tianjin, China

Studies have shown that prevalence of thyroid nodules (TNs) has been increasing recently. However, the factors that may influence TN prevalence is not fully understood. In this study, we aimed to understand the prevalence of TNs and identify possible factors that are associated with the prevalence of TNs in Tianjin, China. Subjects aged 18 years or older were randomly collected and all subjects received thyroid ultrasonography, physical examination and questionnaires. Subjects (n = 2647) were divided into the case group in which the subjects had TNs and the control group in which the subjects did not have TNs. Potential influencing factors on TNs including sex, age, iodine status, thyroid volume, thyroid hormone (TSH), thyroid autoantibody TPOAb, TGAb and living habits were analyzed. Our results showed that the overall TN prevalence was 26.7%. The prevalence of TNs in women was higher than that in men (P < 0.05). TN prevalence increased with age (P < 0.001), and a U-shaped curve relationship between urine iodine concentrations (UICs) and prevalence of TNs was observed. The positive rate of TPOAb and goiter rate in case group was higher than that in control group (P < 0.05). The thyroid volume in case group was larger than that in control group (P < 0.001). Other factors that may influence TNs included high blood pressure, iodized salt, menopause, seafood intake, and education levels. None of UIC, TSH, TPOAb and TGAb were associated with TN prevalence in regression models. In conclusion, our results showed that TNs prevalence in Tianjin was high. TNs prevalence was higher in women than in men, and it increases with age. The older, female, high education level physical labor and goiter are independent risk factors for TNs.

New Biomarkers to Evaluate Hyperandrogenemic Women and Hypogonadal Men

Androgens can have variable effects on men and women. Women may be evaluated for androgen excess for several reasons. Typically, young premenopausal women present with clinical symptoms of hirsutism, alopecia, irregular menses, and/or infertility. The most common cause of these symptoms is polycystic ovary syndrome. After menopause, even though ovaries stop producing estrogen, they continue to produce androgen, and women can have new onset of hirsutism and alopecia. Laboratory evaluation involves measurement of the major ovarian and adrenal androgens. In women, age, phase of the menstrual cycle, menopausal status, obesity, metabolic health, and sex hormone-binding proteins significantly affect total-androgen levels and complicate interpretation. This review will summarize the clinically relevant evaluation of hyperandrogenemia at different life stages in women and highlight pitfalls associated with interpretation of commonly used hormone measurements. Hypogonadism in men is a clinical syndrome characterized by low testosterone and/or low sperm count. Symptoms of hypogonadism include decreased libido, erectile dysfunction, decreased vitality, decreased muscle mass, increased adiposity, depressed mood, osteopenia, and osteoporosis. Hypogonadism is a common disorder in aging men. Hypogonadism is observed rarely in young boys and adolescent men. Based on the defects in testes, hypothalamus, and/or pituitary glands, hypogonadism can be broadly classified as primary, secondary, and mixed hypogonadism. Diagnosis of hypogonadism in men is based on symptoms and laboratory measurement. Biomarkers in use/development for hypogonadism are classified as hormonal, Leydig and Sertoli cell function, semen, genetic/RNA, metabolic, microbiome, and muscle mass-related. These biomarkers are useful for diagnosis of hypogonadism, determination of the type of hypogonadism, identification of the underlying causes, and therapeutic assessment. Measurement of serum testosterone is usually the most important single diagnostic test for male hypogonadism. Patients with primary hypogonadism have low testosterone and increased luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Patients with secondary hypogonadism have low testosterone and low or inappropriately normal LH and FSH. This review provides an overview of hypogonadism in men and a detailed discussion of biomarkers currently in use and in development for diagnosis thereof.

The Cut-off Values of Surrogate Measures for Insulin Sensitivity in a Healthy Population in Korea according to the Korean National Health and Nutrition Examination Survey (KNHANES) 2007-2010

BACKGROUND

This study aimed to identify the gender-specific characteristics of the surrogate measures of insulin resistance and to establish valid cut-off values for metabolic abnormalities in a representative sample in Korea.

METHODS

Data were collected from the datasets of the Korean National Health and Nutrition Examination Survey between 2007 and 2010. The total number of eligible participants was 10,997. We used three measures of insulin resistance: the homeostasis model assessment-insulin resistance (HOMA-IR), McAuley index, and triglyceride and glucose (TyG) index. The estimated cut-off values were determined using the highest score of the Youden index.

RESULTS

The area under the curve (AUC) of the HOMA-IR, McAuley index, and TyG index were 0.737 (95% confidence interval [CI], 0.725-0.750), 0.861 (95% CI, 0.853-0.870), and 0.877 (95% CI, 0.868-0.885), respectively. The cut-off values of the HOMA-IR were 2.20 in men, 2.55 in premenopausal women, and 2.03 in postmenopausal women, and those of the McAuley index were 6.4 in men and 6.6 in premenopausal and postmenopausal women. For the TyG index, the cut-off values were 4.76 in men and 4.71 in premenopausal and postmenopausal women.

CONCLUSION

In conclusion, the present study provides the valid cut-off values of the indirect surrogate measures of insulin sensitivity. These values may be used as reference for insulin sensitivity in a clinical setting and may provide a simple and supplementary method for identifying populations at risk of insulin resistance.

Free androgen index as a determinant of arterial stiffness in menopause: a mediation analysis

OBJECTIVE

Associations of endogenous androgens in menopause with blood pressure (BP) and indices of arterial stiffness are reported, but directional relationships are not clear. Structural equation modeling is a contemporary statistical method, which allows assessment of such relationships and improves pathway understanding.

METHODS

We recruited 411 consecutive apparently healthy postmenopausal women who underwent noninvasive vascular evaluation. This included pulse wave analysis (aortic pressures and arterial wave reflections [augmentation index]), measurement of aortic stiffness by pulse wave velocity (PWV), stiffness index (SI), and flow-mediated dilatation. A cumulative marker combining PWV and SI (combined local and aortic arterial stiffness [CAS]) was also assessed. Free androgen index (FAI) was calculated from circulating total testosterone and sex hormone-binding globulin.

RESULTS

FAI was an independent determinant of systolic BP (SBP) (P = 0.032), SI (P = 0.042), and PWV (P = 0.027). Under structural equation modeling analysis, FAI was a direct predictor for PWV (beta = 0.149, P = 0.014), SI (beta = 0.154, P = 0.022), and CAS (beta = 0.193, P = 0.02), whereas SBP was a parallel mediator of androgen's vascular effects on PWV (beta = 0.280, P < 0.001) and CAS (beta = 0.248, P = 0.004), but not SI (beta = 0.024, P = 0.404). FAI-induced increase in arterial stiffness via flow-mediated dilatation was not established. FAI was not a determinant of augmentation index.

CONCLUSIONS

In healthy postmenopausal women, FAI was directly associated with PWV, SI, and CAS. FAI also directly correlated with SBP, which in turn concurrently increased PWV and CAS. The directional correlations found herein, imply that endogenous androgens may be causally associated with indices of arterial stiffness both directly and indirectly. This hypothesis should be confirmed in further studies with causal design.

Assessment of Salivary Adipokines Resistin, Visfatin, and Ghrelin as Type 2 Diabetes Mellitus Biomarkers

Type 2 diabetes mellitus (T2DM) is emerging as a metabolic epidemic worldwide. Pathologically, dysregulation of many biological pathways precedes hyperglycemia and the clinical diagnosis of T2DM. Changing trajectories along the process of T2DM development necessitates frequent measurement of biomarkers for early identification of at-risk individuals and successful prevention. Increase in circulating inflammatory adipokines has been suggested as predictive of T2DM. Human saliva is an easily accessible biospecimen amenable for painless frequent collection and possesses nearly 50% of serum proteome. In this study, we measured the adipokines resistin, visfatin, TNF-α, and ghrelin as markers for T2DM in unstimulated whole saliva (UWS) using specific assay kits. Resistin and visfatin concentrations were significantly higher in T2DM saliva. Although the concentration of acylated or unacylated ghrelin was lower in diabetic saliva, the decrease was not significant. Since resistin and visfatin are biomarkers integral to T2DM pathology, their salivary assessments may receive clinical acceptance.

Gender- and Age-Specific Relationships Between Phthalate Exposures and Obesity in Shanghai Adults

Phthalate exposure has been reported to be associated with obesity (measured by body mass index [BMI]) and central obesity (measured by waist circumference [WC]). Yet, reported associations and the potential gender and age differences are inconsistent. We conducted a cross-sectional study involving 2330 participants in the fall of 2012. Urinary metabolites of ten phthalates were measured. Height, body weight, and waist circumference (WC) were measured using standardized methods. We performed logistic regression analyses to estimate the association between each urine phthalate metabolite (categorized into quartiles) and obesity and central obesity and conducted an additional, stratified analysis to explore the gender and age differences. In the overall study population, higher urinary levels of MMP, MEHHP, and MECPP were associated with increased ratios of central obesity. When stratifying by gender and central obesity, higher urinary levels of MMP, MEHHP, and MEOHP were associated with increased odds of central obesity in females, whereas MB_zP was significantly associated inversely with central obesity in females. In males, it showed no significant P value for trend (P trend). When stratifying by age in females, higher urinary levels of MEHP, MEOHP, MEHHP, and MECPP were associated with increased odds of central obesity in women aged ≤45 years. In females aged >45 years, it showed no significant P trend. In conclusion, we found that association between phthalates and central obesity was stronger than between phthalates and obesity; association between phthalates and central obesity was stronger in females than in males and was stronger in younger females (aged ≤45 years) than in older females (aged >45 years).

Associations between postmenopausal endogenous sex hormones and C-reactive protein: a clearer picture with regional adiposity adjustment?

OBJECTIVE

To better understand the pathogenesis of inflammatory-related diseases after menopause, we studied the adiposity-independent association between endogenous sex hormones and C-reactive protein (CRP), a biomarker of inflammation.

METHODS

We conducted a secondary, cross-sectional analysis of baseline data from the Alberta Physical Activity and Breast Cancer Prevention Trial (2003-2007), including 319 healthy, postmenopausal women not using hormone therapy. Multivariable linear regression models related serum CRP levels to estrogens, androgens, and sex hormone-binding globulin (SHBG), all on the natural logarithmic scale. Models were adjusted for age, lipids, medication, and former menopausal hormone therapy use, and also for adiposity (body mass index [BMI], per cent body fat [via whole-body dual x-ray absorptiometry], or intra-abdominal fat area [via computed tomography]).

RESULTS

Without adiposity adjustment, estrone, total estradiol, and free estradiol were significantly positively associated with CRP, whereas SHBG was significantly inversely associated with CRP. Of all adiposity measures, adjustment for BMI caused the greatest attenuation of CRP-estrogen associations; only free estradiol (β = 0.24, 95% confidence interval [CI] 0.06, 0.43) and SHBG (β = -0.37, 95% CI -0.60, -0.13) associations remained significant. Inverse associations between CRP-total testosterone became stronger with BMI adjustment (β = -0.20, 95% CI -0.40, -0.01). Differential associations across categories of BMI, former hormone therapy use, and years since menopause were suggestive, but not statistically significant (Pheterogeneity > 0.05).

CONCLUSIONS

Prospective and systems epidemiological studies are needed to understand whether or not the cross-sectional associations we observed, independent of adiposity, between CRP-SHBG, CRP-total testosterone, and CRP-free estradiol, are causal.

New biomarkers for diagnosis and management of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder affecting young women. Even though the definition of PCOS has changed over the years, all diagnostic criteria include two or more of the following: oligomenorrhea/oligoovulation/anovulation, androgen excess and polycystic ovaries (PCO). Traditional method of assessing the ovarian morphology has been transvaginal pelvic ultrasound. Recent studies support that serum anti-Mullerian hormone (AMH) levels correlate with the number of ovarian follicles and cysts. Hence, measurement of AMH is adequate to make the diagnosis. Traditionally, hyperandrogenemia has been assessed by measuring total-testosterone. The literature stresses the importance of sex hormone binding globulin (SHBG) measurements and bioavailable-testosterone and free-testosterone calculations, because insulin resistance decreases SHBG, lowers total-testosterone, and leads to under-estimation of bioavailable- and free-testosterone. Since 50-60% of PCOS patients have metabolic syndrome, assessment of metabolic risk is also necessary. It is important to diagnose insulin resistance before development of glucose intolerance and diabetes. This requires measurements of not only plasma glucose but also insulin concentrations. Determination of HgBA1 can be informative as well. This review aims to present an accurate and cost-effective approach to diagnosis and management of PCOS.

Sex Differences in the Association of Urinary Concentrations of Phthalates Metabolites with Self-Reported Diabetes and Cardiovascular Diseases in Shanghai Adults

Phthalate exposure was reported to be associated with diabetes mellitus (DM) and cardiovascular disease (CVD). Yet, reported associations and the potential sex differences are inconsistent. We conducted a cross-sectional study involving 2330 participants in the Fall of 2012. Urinary metabolites of 10 phthalates were measured. The status of having DM and CVD-related outcomes were self-reported. In the overall study population, the logistic regression analyses showed that the urinary levels of mono-2-ethyl-5-oxohexyphthalate (MEOHP), mono-2-ethyl-5-hydroxyhexylphthalate(MEHHP) and mono-2-ethyl-5-carboxypentylphthalate (MECPP) were positively associated with DM. Higher urinary levels of monomethyl phthalate (MMP) and mono-2-carboxymethyl-hexyl phthalate (MCMHP) were associated with increased odds of hyperlipidemia, while mono-2-ethylhexylphthalate (MEHP) was significantly inverse-associated with hyperlipidemia. We did not observe significant associations for other CVD-related outcomes with phthalate metabolites. When stratifying by sex, MEHHP, MEOHP, MECPP, MCMHP and the micromolar sums of the oxidative metabolites of DEHP (ΣDEHP_ox) were all significantly related to DM in males, but not in females. No significant sex differences were found in CVD-related outcomes, except the sporadic associations between phthalates and hyperlipidemia. These findings highlight the importance of investigating the sex-specific relationship between phthalates exposure and DM.

Socioeconomic Deprivation as Measured by the Index of Multiple Deprivation and Its Association with Low Sex Hormone Binding Globulin in Women

Objective:

Sex hormone binding globulin (SHBG) is a marker of insulin resistance. Given established links between BMI and socioeconomic disadvantage, we investigated how SHBG varies by index of multiple deprivation (IMD).

Research Design and Methods:

Using laboratory data from a Midlands UK population of mixed ethnicity, we examined the relation between blood concentrations of SHBG and IMD in 1160 women aged between 17 and 71 years. Women with a serum SHBG >250 nmol/L were excluded.

Results:

Mean age was 28.7 (95% confidence interval (CI) 28.2–29.1) years. 48.2% of women were of Caucasian origin, 15.5% of Southern Asian ethnicity and 2.6% were of African or other origin (33.7% were of unknown origin).

SHBG increased with age (Spearman’s ρ=0.195; p<0.001). A higher proportion of women of South Asian origin versus other ethnic groups had an SHBG <30 nmol/L (OR 1.93 (95% CI 1.37–2.71)).

SHBG level was lower in individuals with greater socioeconomic disadvantage as measured by IMD (Spearman's ρ= -0.09; p=0.004 for SHBG versus IMD).

In multivariate logistic regression, IMD women in the quartiles 2–5 (higher socioeconomic disadvantage) were more likely to have an SHBG <30 nmol/L (compatible with significant insulin resistance) versus quartile 1 (odds ratio (OR) 1.71 (95% confidence interval (CI) 1.17–2.53), adjusted for age (OR=0.97 (95% CI 0.95–0.98)) and ethnicity (for South Asian ethnicity OR=2.00 (95% CI 1.42–2.81) versus the rest).

Conclusion:

Lower SHBG levels in women are associated with a higher level of socioeconomic disadvantage. Given the known association between lower SHBG and higher plasma glucose, our findings suggest a link between socioeconomic disadvantage and future risk of type 2 diabetes.

Cross-sectional study of factors influencing sex hormone-binding globulin concentrations in normally cycling premenopausal women

OBJECTIVE

To assess the relationship between SHBG and 18 other hormonal and metabolic parameters in well characterized, normally cycling premenopausal women.

DESIGN

Cross-sectional study.

SETTING

University general clinical research center.

SUBJECT(S)

A total of 319 young healthy women with ovulatory menstrual cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Midfollicular serum SHBG concentrations.

RESULT(S)

In our final linear regression model, SHBG was negatively associated with bioavailable T and positively associated with adiponectin, associations that were independent from other parameters. SHBG was also positively associated with estrone sulfate, but only when taking into account confounding variables. Unexpectedly, there was no straightforward relationship between SHBG and insulin resistance according to homeostasis-model assessment.

CONCLUSION(S)

Our results highlight the link between androgen action, as reflected by bioavailable T, and circulating SHBG concentrations in all premenopausal women and speak to the importance of the relationship between SHBG and adiponectin, which is at least in part independent from androgen action.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00393172.

Metabolic Syndrome and Menopause: Pathophysiology, Clinical and Diagnostic Significance

Menopause is a risk factor for cardiometabolic diseases, including metabolic syndrome (MetS), type 2 diabetes, and cardiovascular diseases. MetS is a constellation of interdependent factors such as insulin resistance, abdominal obesity, dyslipidemia, and hypertension. The prevalence of MetS in postmenopause is due to loss of the protective role of estrogens and increased circulating androgens resulting in changes to body fat distribution and development of abdominal obesity. Excessive visceral adipose tissue plays an important role due to synthesis and secretion of bioactive substances such as adipocytokines, proinflammatory cytokines, reactive oxygen species, prothrombotic, and vasoconstrictor factors. MetS may also impact risk assessment of breast cancer, osteoporosis and chronic kidney disease, and quality of life during the menopausal transition. Increased MetS has stimulated the exploration of new laboratory tests for early detection and therapies.

Literature-based discovery of salivary biomarkers for type 2 diabetes mellitus

The alarming increase in type 2 diabetes mellitus (T2DM) underscores the need for efficient screening and preventive strategies. Select protein biomarker profiles emerge over time during T2DM development. Periodic evaluation of these markers will increase the predictive ability of diabetes risk scores. Noninvasive methods for frequent measurements of biomarkers are increasingly being investigated. Application of salivary diagnostics has gained importance with the establishment of significant similarities between the salivary and serum proteomes. The objective of this study is to identify T2DM-specific salivary biomarkers by literature-based discovery. A serial interrogation of the PubMed database was performed using MeSH terms of specific T2DM pathological processes in primary and secondary iterations to compile cohorts of T2DM-specific serum markers. Subsequent search consisted of mining for the identified serum markers in human saliva. More than 60% of T2DM-associated serum proteins have been measured in saliva. Nearly half of these proteins have been reported in diabetic saliva. Measurements of salivary lipids and oxidative stress markers that can exhibit correlated saliva plasma ratio could constitute reliable factors for T2DM risk assessment. We conclude that a high percentage of T2DM-associated serum proteins can be measured in saliva, which offers an attractive and economical strategy for T2DM screening.

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.

Relationship between the Prevalence of Thyroid Nodules and Metabolic Syndrome in the Iodine-Adequate Area of Hangzhou, China: A Cross-Sectional and Cohort Study

Objective. The association between thyroid nodule (TN) prevalence and metabolic syndrome (MetS) has only rarely been examined in iodine-adequate areas and needs further clarification. We investigated correlations between MetS and TN prevalence in the iodine-adequate area of Hangzhou, China. Material and Method. A cross-sectional study that screened and recruited individuals for cohort research 3 years later. The 13522 subjects (8926 men, 4596 women) were screened in 2009 for all MetS components, thyroid ultrasound (US), and thyroid function. Cohort research recruited 1610 subjects who were screened in both 2009 and 2012, of whom 1061 underwent follow-up research. Results. The prevalence of TN was higher in the MetS (+) group than in the MetS (-) group (χ (2) = 69.63, P < 0.001) and higher in women than in men (χ (2) = 11.65, P = 0.001). Waist circumference (WC) was positively related to the prevalence of TN (OR = 1.022, P < 0.001). Individuals with greater WC in 2009 were more likely to suffer from TN in 2012 (RR = 1.434, P = 0.024). Elevated triglyceride level was a risk factor for developing new TN (RR = 1.001, P = 0.035). Conclusion. Both greater WC and elevated triglycerides are risk factors for new TN in this iodine-adequate area in China.

Estrogen: a master regulator of bioenergetic systems in the brain and body

Estrogen is a fundamental regulator of the metabolic system of the female brain and body. Within the brain, estrogen regulates glucose transport, aerobic glycolysis, and mitochondrial function to generate ATP. In the body, estrogen protects against adiposity, insulin resistance, and type II diabetes, and regulates energy intake and expenditure. During menopause, decline in circulating estrogen is coincident with decline in brain bioenergetics and shift towards a metabolically compromised phenotype. Compensatory bioenergetic adaptations, or lack thereof, to estrogen loss could determine risk of late-onset Alzheimer's disease. Estrogen coordinates brain and body metabolism, such that peripheral metabolic state can indicate bioenergetic status of the brain. By generating biomarker profiles that encompass peripheral metabolic changes occurring with menopause, individual risk profiles for decreased brain bioenergetics and cognitive decline can be created. Biomarker profiles could identify women at risk while also serving as indicators of efficacy of hormone therapy or other preventative interventions.

Role of sex steroids, intrahepatic fat and liver enzymes in the association between SHBG and metabolic features

BACKGROUND

SHBG and liver enzymes levels are both associated with the risk of type 2 diabetes. However, the relationship between SHBG with liver enzymes and intrahepatic fat content remain poorly understood.

OBJECTIVE

To investigate whether SHBG is correlated with glucose and lipids levels and whether this association depends on fatty liver content, liver enzymes or sex hormone concentrations.

DESIGN AND PATIENTS

We studied 233 dysmetabolic men with measures of plasma SHBG, total testosterone, 17β-oestradiol, glucose, adiponectin, liver enzymes and hepatokines. Intrahepatic liver fat and visceral fat contents were measured by magnetic resonance imaging in 108 of these individuals.

RESULTS

After adjustment for age, SHBG concentration was inversely correlated with fasting glucose (βstandardized  = -0·21, P = 0·0007), HbA1c (βstandardized  = -0·27, P < 0·0001), triglycerides (βstandardized  = -0·19, P = 0·003) and positively correlated with HDL-Cholesterol (βstandardized  = 0·14, P = 0·03). These correlations persisted after adjustment for either total testosterone or 17β-oestradiol levels. SHBG was not related to either fetuin A or FGF 21 concentrations. The inverse association of SHBG with HbA1c and glycaemia was not altered after adjusting for liver markers but was no longer significant after adjustment for hepatic fat content.

CONCLUSION

The significant association between SHBG and fasting glycaemia, HbA1c and lipid levels in dysmetabolic men was not related to either sex hormones or markers of liver function, but was dependent on intrahepatic fat. This suggests that intrahepatic fat, but not alterations in liver function markers, may be involved in the association between SHBG and glucose and lipid metabolism.

Liver fat and SHBG affect insulin resistance in midlife women: the Study of Women's Health Across the Nation (SWAN)

OBJECTIVE

The liver is an insulin-responsive organ that contributes significantly to both whole body insulin sensitivity and availability of sex steroids through the production of sex hormone binding globulin (SHBG). Our objective was to explore whether lower SHBG was associated with ectopic liver fat and mediated its effect on insulin resistance in The Study of Women's Health Across the Nation (SWAN).

DESIGN AND METHODS

A subset of midlife African American and Caucasian women from SWAN (n = 208; 50.9 ± 0.18 yrs; 71% Caucasian) had computed tomography scans to quantify visceral, subcutaneous and liver fat. Blood samples were collected and assayed for hormonal and metabolic markers.

RESULTS

The cohort, while overweight, was generally healthy, and both liver fat and SHBG were unaffected by menopausal stage or race. Both higher liver fat and lower SHBG levels were significantly associated with higher insulin concentrations after adjustment for adiposity (r = -0.25, P < 0.001 and r = -0.18, P = 0.01). SHBG and liver fat had additive effects on insulin concentrations such that women with the lowest SHBG and the highest fat levels had the highest values (interaction P = 0.09). The association between SHBG and insulin was more apparent among women with fattier livers. SHBG and liver fat appear to have independent effects on insulin levels as adjustment for each other did not diminish the strength of either association (P = 0.023 and 0.001 respectively).

CONCLUSION

These results confirmed the strong independent associations between increased liver fat and decreased SHBG with increased metabolic risk in midlife women. Further these data underscore the need for additional research into the role of liver fat in modifying SHBG's influence on insulin levels.

The complex interaction between obesity, metabolic syndrome and reproductive axis: a narrative review

The aim of this narrative review is to provide current evidence for the interaction between obesity, metabolic syndrome (MS) and reproductive axis. Gonadotropin-releasing hormone (GnRH) pulses and, consequently, normal function of reproductive (hypothalamus-pituitary-gonadal) axis depend on normal energy balance, which presupposes sufficient food intake, reasonable energy consumption and average thermoregulatory costs. In case of an energy imbalance, reproductive dysfunction may occur. In young women, excessive leanness is accompanied by puberty delay, whereas premature puberty might be a manifestation of obesity. In a similar way, obesity in men affects fertility. Excess adipose tissue results in increased conversion of testosterone to estradiol, which may lead to secondary hypogonadism through reproductive axis suppression. Moreover, oxidative stress at the level of the testicular micro-environment may result in decreased spermatogenesis and sperm damage. Products of the adipocyte, such as leptin, adiponectin and resistin, and gut peptides, such as ghrelin, are considered to be crucial in the interaction between energy balance and reproduction. Finally, an indirect evidence for the interplay between MS and reproductive axis is the fact that when treating components of one, parameters of the other can be improved as well. These therapeutic interventions include lifestyle modifications, pharmacological agents, such as sex hormone replacement therapy, and surgical procedures. Although many issues remain unclear, the elucidation of the complex interaction between MS and reproductive axis will have obvious clinical implications in the therapeutic approach of both entities.

The relationship between endogenous androgens and body fat distribution in early and late postmenopausal women

Objectives

To investigate the relationship between endogenous androgens and body fat distribution in early and late postmenopausal women.

Materials and Methods

We enrolled postmenopausal women consisting of an early group (≤5 years since menopause, n = 105) and a late group (≥10 years since menopause, n = 107). Each group was subdivided into normal weight (BMI <24 kg/m²) group, overweight and obese (BMI ≥24 kg/m²) group. Fasting total testosterone (T), dehydroepiandrosterone-sulfate (DHEA-S) and sex hormone-binding globulin (SHBG) levels were measured. Body fat distribution was evaluated by dual-energy X-ray absorptiometry (DEXA).

Results

Late postmenopausal women had a higher proportion of body fat than early postmenopausal women. The body fat of the overweight and obese women had a greater tendency to accumulate in the abdomen compared with the normal weight women both in early and late postmenopausal groups. The overweight and obese women had a higher free testosterone (FT) than the normal weight women in early postmenopausal women (P<0.05). In late postmenopausal women, the overweight and obese women had higher DHEA-S levels than normal weight women (P<0.05). No direct relationship was observed between the T levels and body fat distribution both in early and late postmenopausal groups (P>0.05).The FT in early postmenopausal women and the DHEA-S levels in late postmenopausal women correlated positively with the trunk/leg fat ratio (T/L) and the proportion of android fat whereas correlated negatively with the proportion of gynoid fat in the partial correlation and multiple linear regression analyses (all P<0.05).

Conclusions

Serum T levels do not correlate directly with body fat distribution, the FT in early postmenopausal women and DHEA-S levels in late postmenopausal women correlate positively with abdominal fat accumulation.

Sex hormone binding globulin and insulin resistance

Sex hormone binding globulin (SHBG) is a glycoprotein composed of two 373-amino-acid subunits. The SHBG gene and a promotor region have been identified. The SHBG receptor has yet to be cloned but is known to act through a G-protein-linked second-messenger system following plasma membrane binding. The principal function of SHBG has traditionally been considered to be that of a transport protein for sex steroids, regulating circulating concentrations of free (unbound) hormones and their transport to target tissues. Recent research suggests that SHBG has functions in addition to the binding and transport of sex steroids. Observational studies have associated a low SHBG concentration with an increased incidence of type 2 diabetes mellitus (DM) independent of sex hormone levels in men and women. Genetic studies using Mendelian randomization analysis linking three single nucleotide polymorphisms of the SHBG gene to risk of developing type 2 DM suggest SHBG may have a role in the pathogenesis of type 2 DM. The correlation between SHBG and insulin resistance that is evident in a number of cross-sectional studies is in keeping with the suggestion that the association between SHBG and incidence of type 2 DM is explained by insulin resistance. Several potential mechanisms may account for this association, including the identification of dietary factors that influence SHBG gene transcription. Further research to characterize the SHBG-receptor and the SHBG second messenger system is required. An interventional study examining the effects on insulin resistance of altering SHBG concentrations may help in determining whether this association is causal.

The contribution of SHBG to the variation in HOMA-IR is not dependent on endogenous oestrogen or androgen levels in postmenopausal women

OBJECTIVE

Sex hormone-binding globulin (SHBG) is a robust predictor of insulin resistance. Whether this is independent of circulating sex steroid levels remains uncertain. The aim of this study was to investigate the determinants of SHBG in postmenopausal women and whether the relationship between SHBG and insulin resistance is independent of oestrogen and androgen levels.

DESIGN

A cross-sectional study of naturally and surgically menopausal women.

PARTICIPANTS

Seven hundred and sixty three postmenopausal women not using any systemic hormone therapy, mean age 54·4 ± 5·8 years, recruited in the US, Canada, Australia, UK and Sweden between July 2004 and February 2005.

MEASUREMENTS

Relationships between log-transformed (ln) SHBG and ln homoeostasis model assessment for insulin resistance (HOMA-IR) were explored, taking into account age, body mass index (BMI), blood pressure (BP) and circulating oestradiol, oestrone, testosterone and dihydrotestosterone.

RESULTS

Taking into account age, race, years since menopause, menopause type, BMI, BP, prior postmenopausal hormone use and the sex steroids measured, 34·4% of the variation in SHBG could be explained by the model that included negative contributions by HOMA-IR, BMI and diastolic BP, and a positive contribution by total testosterone (P < 0·001). None of the sex steroids made independent contributions to HOMA-IR, which was best explained by the model that included BMI, SHBG, systolic BP and surgical menopause, with each variable being positively related to HOMA-IR (r(2) = 0·3152, P = 0·03).

CONCLUSIONS

The relationship between SHBG and HOMA-IR, as an estimate of insulin resistance, is not explained by endogenous oestrogen and androgen levels and is, at least in part, independent of BMI in postmenopausal women.

Effects of aerobic exercise training on serum sex hormone binding globulin, body fat index, and metabolic syndrome factors in obese postmenopausal women

BACKGROUND

The percentage of obese postmenopausal women with metabolic syndrome is rising, and physical factors associated with the metabolic syndrome prevalence or incidence are also rising, including high body mass index (BMI), visceral fat area (VFA), low plasma sex hormone-binding globulin (SHBG) levels, and low cardiorespiratory fitness. Therefore, we investigated the influence of aerobic exercise on SHBG, body fat index (BFI), and metabolic syndrome factors in obese postmenopausal Korean women.

METHODS

Thirty healthy postmenopausal, women aged 53.46 ± 2.4 years and with over 32% body fat, were randomly assigned to an aerobic exercise group (EX; n=15) or to a "nonexercise" control (Con; n=15) group. The primary outcome measurements were serum SHBG, lipid profiles, insulin levels, and metabolic syndrome factors. Secondary outcome measurements were body composition, VFA, blood pressure (BP), and homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Posttraining body weight and BFI (P<0.05), total cholesterol, glucose, and insulin levels (P<0.01), BP, and HOMA-IR (P<0.001) decreased, whereas SHBG (P<0.001) and metabolic syndrome factors (P<0.01) improved in the exercise group but not in the control group. SHBG levels also showed a significant positive correlation with high-density lipoprotein cholesterol (HDL-C) and significant negative correlations withglucose, diastolic blood pressure, fat mass, BMI, and percent body fat (P<0.05).

CONCLUSIONS

Our findings indicate that aerobic exercise improves body composition, SHBG, insulin levels, and metabolic syndrome factors. These findings suggest that in obesepostmenopausal Korean women, 16 weeks of aerobic exercise is effective for preventing the metabolic syndrome caused by obesity.

Low serum sex hormone-binding globulin: marker of inflammation?

BACKGROUND

Low sex hormone-binding globulin (SHBG) is associated with metabolic syndrome (MetS), but its relationship with inflammation is unclear.

METHODS

This cross-sectional study included 696 subjects (255 men, 235 pre-menopausal women, and 206 postmenopausal women). Body mass index, waist circumference, blood pressure, lipid profiles, plasma glucose, insulin, FSH, LH, total testosterone (TT), estradiol, SHBG, dehydroepiandrosterone sulfate (DHEA-S), and hs-CRP concentrations were measured. MetS was defined according to the updated National Cholesterol Education Program criteria with modification of waist circumference for Asians.

RESULTS

Serum hs-CRP and SHBG were negatively correlated in men (r=-0.29, p<0.001), pre-menopausal women (r=-0.38, p<0.001), and postmenopausal women (r=-0.27, p<0.001). In men, TT and hs-CRP showed a negative association (r=-0.25, p<0.001), but the association was attenuated after adjusting for SHBG (r=-0.14, p=0.039). Multivariate regression models showed that SHBG was independently associated with hs-CRP in men (r=-0.18, p=0.009), pre-menopausal women (r=-0.15, p=0.025), and postmenopausal women (r=-0.21, p=0.005), adjusted for age, MetS components, insulin resistance, low-density lipoprotein-cholesterol, and serum sex hormone levels.

CONCLUSIONS

Serum SHBG and hs-CRP concentrations were inversely correlated in men, pre-menoposal, and post-menopausal women independently.

Correlation between insulin resistance and breast elasticity heterogeneity measured by shear wave elastography in premenopausal women - a pilot study

INTRODUCTION

Recent studies have demonstrated a strong correlation between obesity, insulin resistance, increased insulin and insulin-like growth factor levels and the risk of breast cancer. Our study was aimed at exploring correlations between glucose, insulin, insulin resistance, obesity and quantitatively estimated breast elasticity in healthy women.

MATERIAL AND METHODS

The pilot study included 37 premenopausal women aged 22-45 years who underwent B-mode sonography and real-time shear wave elastography. Blood was collected for fasting insulin and glucose, and HOMA insulin resistance index was calculated.

RESULTS

The mean elasticity of glandular and fatty tissue measured in both breasts was 12.5 ±3.5 kPa and 10.9 ±3.7 kPa respectively. Insulin levels did not correlate with glandular tissue elasticity (Rs=-0.23, p=0.15), but nearly correlated with fat tissue elasticity (Rs=-0.30, p=0.06), in outer quadrants significantly (Rs=-0.38, p=0.02). Interestingly, a strong correlation of insulin and insulin resistance with elasticity heterogeneity was found in fatty tissue (Rs=-0.59, p<0.001 and Rs=-0.60, p<0.001 respectively). The heterogeneity of fatty tissue but not glandular elasticity also correlated with body mass index.

CONCLUSIONS

Insulin levels and insulin resistance correlate with breast fat tissue heterogeneity, but their role in breast pathology remains unclear.

Body mass index and its correlation to metabolic and hormone parameters in postmenopausal Spanish women

OBJECTIVE

To assess body weight composition in postmenopausal women and determine correlations with metabolic and hormonal parameters.

METHODS

Medical records of 574 postmenopausal Caucasian Spanish women first time attending a menopause clinic were retrospectively reviewed. Retrieved information included general demographic data, type of menopause, time since menopause onset and baseline hormonal and metabolic parameters. A body mass index (BMI) value of >28.8 kg/m(2) was used to define obesity. The metabolic syndrome (METS) was diagnosed with three or more criteria: fasting glycemia ≥ 100 mg/dL, high density lipoprotein cholesterol (HDL-C) <50 mg/dL, triglycerides (TG) ≥ 150 mg/dL, blood pressure ≥ 130/85 mmHg and obesity (as defined above).

RESULTS

Mean age of the whole cohort was 49.9 ± 6.1 years, with 66% having a natural menopause. A 38.9% and 23.1% of all women were obese or had the METS, respectively. Obese women were older, had a higher parity, smoked less, had more time since menopause onset and a higher rate of surgical menopause as compared to non-obese ones (p = 0.001). BMI values positively correlated with age, time since menopause, parity, and glucose, TG and systolic blood pressure levels; displaying an inverse correlation with HDL-C and SHBG levels. SHBG levels inversely correlated with glucose, TG, HDL-C and systolic blood pressure levels.

CONCLUSION

In this Spanish postmenopausal population BMI significantly increased with age, time since menopause and parity displaying significant correlations with hormonal and metabolic parameters.

Cardiovascular and cancer safety of testosterone in women

PURPOSE OF REVIEW

To examine the recent data pertaining to the relationships between testosterone and cardiovascular disease (CVD) and cancer in women.

RECENT FINDINGS

Despite the entrenched belief that higher blood levels of testosterone increase the risk of CVD in women, data from recent observational studies mostly show an inverse relationship between testosterone and CVD risk. One pilot study suggests favorable effects of nonoral testosterone treatment of women with established congestive cardiac failure which merits further evaluation. The relationship between endogenous testosterone production and breast cancer risk remains contentious, with recent studies indicating either no relationship, or a possible increase in risk when estrone and estradiol are not taken into account. No randomized controlled trial of testosterone therapy has been sufficiently large or of sufficient duration to establish whether such treatment may influence breast cancer occurrence. There does not appear to be an association between testosterone and endometrial cancer, or other malignancies on review of published studies.

SUMMARY

Testosterone is inversely associated with increased CVD risk in women, whereas low sex hormone binding globulin increases CVD risk. The relationship between testosterone and breast cancer remains unclear, although a clear signal of risk has not emerged from studies of women treated with testosterone therapy over the past decade.

Metabolic and hormonal parameters in post-menopausal women 10 years after transdermal oestradiol treatment, alone or combined to micronized oral progesterone

BACKGROUND

In the post-Women's Health Initiative Study era few post-menopausal women complete long term hormonal treatment (HT).

OBJECTIVE

To analyse metabolic/hormonal parameters and frequency of the metabolic syndrome (METS) in post-menopausal women after 10 years of HT.

METHODS

Retrospective data from parallel cohorts of post-menopausal women receiving HT for 10 years was analysed. Regimens included: transdermal oestradiol (50 microg) (n=22), sequential cyclic HT with transdermal oestradiol (50 microg) plus 200 mg/day micronized oral progesterone (cycle days 12-25) (n=83), or continuous combined HT with transdermal oestradiol (50 microg) plus 100 mg/day micronized oral progesterone (n=46). A group of women who elected not to use HT served as a control group (n=35).

RESULTS

Frequency of the METS did not significantly increase after 10 years of HT. Oestradiol and sex hormone binding globulin (SHBG) levels displayed a significant increase compared to baseline after 10 years of HT (all regimens). These values were significant higher when compared to the control group. Glucose levels were significantly higher after 10 years in women receiving the sequential cyclic regimen. Although not reaching statistical significance, there was a trend for transdermal oestradiol alone to increase HDL-C and decrease triglyceride levels.

CONCLUSION

Serum oestradiol and SHBG levels were significantly higher after 10 years of transdermal oestradiol, alone or combined with micronized oral progesterone, without differences observed in serum metabolic parameters. More research through randomised clinical trials is required.

Live prey enrichment, with particular emphasis on HUFAs, as limiting factor in false percula clownfish (Amphiprion ocellaris, Pomacentridae) larval development and metamorphosis: molecular and biochemical implications

In fast growing organisms, like fish larvae, fatty acids provided through live prey are essential to satisfy high energy demand and are required to promote growth. Therefore, in recent decades, a great amount of research has been directed towards the development of lipid enrichment in order to improve larval fish survival and growth. However, in fish, the biochemical and molecular processes related to highly unsaturated fatty acid (HUFA) administration are still poorly understood. In the current study, the false percula clownfish, a short larval phase marine species, was used as an experimental model and the effects of a standard and a HUFAs-enriched diet were tested through a molecular, biochemical, ultrastructural and morphometric approach. Our results support the hypothesis that HUFA administration may improve larval development through the presence of better structured mitochondria, a higher synthesis of energy compounds and coenzymes with a central position in the metabolism, with respect to controls. This higher energy status was confirmed by better growth performance and a shorter larval phase in larvae fed with an enriched diet with respect to the control. This strategy of rapid growth and early energy storage may be considered positively adaptive and beneficial to the survival of this species.

Obesity is Related to Increased Menopausal Symptoms among Spanish Women

Objective.

To assess the metabolic syndrome (METS) and its components in postmenopausal women using updated diagnostic criteria and explore their relation to menopausal symptom severity.

Method.

Medical records of the first visit of 574 postmenopausal Caucasian Spanish women attending a menopause clinic were retrospectively reviewed. Recorded information included general demographic data, type of menopause, menopausal symptom intensity (Kupperman index) and baseline hormonal and metabolic parameters. METS was established if three or more of the following criteria were met: body mass index (BMI) >28.8 kg/m2, fasting glycaemia >100 mg/dL, high-density lipoprotein cholesterol (HDL-C) <50 mg/dL, triglycerides ≥150 mg/dL and blood pressure ≥130/85 mmHg.

Results

Mean ± SD age of the whole cohort was 49.9 ± 6.1 years, 66% had natural menopause and 38.9% were obese. In all, 23.1% met diagnostic criteria for METS who were significantly older and displayed higher rates of being married, obesity and abnormal glucose, triglyceride, HDL-C, low-density lipoprotein cholesterol and blood pressure values, when compared with those without the syndrome. The mean Kupperman index score for the whole sample was 26.4 ± 10.6, with 73.8% displaying moderate to severe scores (20 or more). Logistic regression analysis determined that obesity and marriage status were independent risk factors related to more severe menopausal symptoms (Kupperman index scores of 20 or more).

Conclusion.

Although METS was observed in a lower frequency than previous reports, obesity was associated with more severe menopausal symptoms among postmenopausal Spanish women.

Alkaline phosphatase and percentage body fat predict circulating C-reactive protein in premenopausal women

C-reactive protein (CRP) is considered a marker of inflammation, which is a risk factor for many chronic diseases. However, determinants of CRP remain unclear and were studied in a strictly defined cohort of healthy premenopausal women (n=233) using multiple regression models. Independent predictors of serum CRP (model R(2)=0.59) were percentage body fat, serum alkaline phosphatase (ALP), sex hormone-binding globulin and white blood cell count. The close association between CRP and ALP suggests that enzymatic activity of ALP may be important for the anti-inflammatory effects of CRP, which should be confirmed with additional studies.

Hyperglycemia in postmenopausal women screened for the metabolic syndrome is associated to increased sexual complaints

BACKGROUND

Postmenopausal metabolic changes increase cardiovascular risk and impair quality of life (QoL). Despite this, few reports have addressed the association of these changes with female sexuality.

OBJECTIVE

To determine the association between the metabolic syndrome (METS), and its components, and female sexuality.

METHODS

Data of sexually active postmenopausal women who participated in a METS screening program who filled out the menopause-specific quality of life questionnaire (MENQOL) were assessed. Specifically the sexual domain of the MENQOL was analyzed in regard to mean total and item scores (decreased libido, vaginal dryness, and sexual avoidance). Criteria of the Third Adult Treatment Panel (ATP III) were used to identify women with the METS.

RESULTS

Two hundred six women fulfilled inclusion criteria. Mean age of participants was 54 ± 6.9 years (median: 54 years). Prevalence of the METS in this sexually active postmenopausal series was 39.8%. About 52.9% of them presented abdominal obesity, 35.4% hypertension, 55.8% high triglycerides, 17.5% hyperglycemia, and 59.7% decreased high density lipoprotein cholesterol (HDL-C). Women with the METS as compared with those without the syndrome displayed no significant differences in MENQOL sexual scorings (total or of its composing items). Equally there were also no score differences among those presenting any of the five components of the METS, except women with hyperglycemia who significantly displayed a higher total sexual domain score (5.6 ± 2.1 vs. 4.8 ± 2.3, p < 0.05) in association to a higher mean score in the decreased libido item (6.0 ± 2.3 vs. 4.8 ± 2.6, p < 0.01). After controlling for several confounding factors, logistic regression confirmed that women with hyperglycemia were significantly at higher risk for presenting decreased libido (higher item score, OR 2.4, CI 95%: 1.0-5.7, p < 0.05) and more impaired sexuality (higher total MENQOL sexual domain score: OR, 2.5, CI 95%: 1.1-5.4, p < 0.05).

CONCLUSION

Despite the limitations of this study, as assessed with the MENQOL, hyperglycemia in postmenopausal women screened for the METS was associated to a negative impact in sexuality. More research is warranted in this regard.