Relationship between dietary carbohydrates intake and circulating sex hormone-binding globulin levels in postmenopausal women

Recent Advances on Sex Hormone-Binding Globulin Regulation by Nutritional Factors: Clinical Implications

Sex hormone-binding globulin (SHBG) is a homodimeric glycoprotein produced by the human liver and secreted into the systemic circulation where it binds with high affinity sex steroids regulating their availability in blood and accessibility to target tissues. Plasma SHBG levels are altered in metabolic disorders such as obesity, anorexia, and insulin resistance. Several reports have shown that diets in terms of total calories or fat, fiber, or protein content can alter plasma SHBG levels. However, there are many components in a diet that can affect SHBG gene expression in the liver. In order to unravel the molecular mechanisms by which diets regulate SHBG production, it would be necessary to analyze single diet components and/or nutritional factors. This review summarizes the recent advances in identifying different nutritional factors regulating SHBG production and the related molecular mechanism, as well as the clinical implications.

Examining the causal relationship between sex hormone-binding globulin (SHBG) and infertility: A Mendelian randomization study

BACKGROUND

The causal relationship between sex hormone-binding globulin (SHBG) and infertility has remained unclear. Thus, we used Mendelian randomization (MR) to investigate this relationship.

METHODS

Risk factors for SHBG were extracted from European individuals within the UK Biobank using single-nucleotide polymorphism (SNP) data. Summary-level data for infertility outcomes were obtained from the FinnGen dataset. The causal relationship between SHBG and infertility was examined using inverse variance weighted, weighted model, weighted median, and MR-Egger regression analyses. Additionally, Cochran's Q test and Egger intercept tests were used to confirm the heterogeneity and pleiotropy of identified instrumental variables (IVs).

RESULTS

Our findings revealed a significant negative association between sex hormone-binding globulin (SHBG) levels and infertility, particularly with anovulation, a specific form of female infertility. However, SHBG did not exert a causal impact on male infertility or on female infertility of tubal origin.

CONCLUSIONS

SHBG expression offers protection against the development of certain types of female infertility, suggesting it is a potential therapeutic target for infertility.

Low Diet Quality and Nutritional Knowledge in Women with Endometriosis: A Pilot Study

Endometriosis is a chronic gynecological disease characterized by ectopic endometrial tissue outside the uterus that can cause chronic pain, dysmenorrhea, fatigue, and infertility. The aim of this study was to assess diet quality and nutritional knowledge of women with endometriosis. A questionnaire was used to collect data on lifestyle, dietary habits and nutritional knowledge from 90 women. More than 80% of women with endometriosis (82.2%) confirmed that diet and lifestyle are related to the progression of endometriosis. After being diagnosed with endometriosis, 77.3% of respondents reported a change in their dietary habits and made various changes to their diet by increasing or eliminating the consumption of certain foods. The majority declared reducing pro-inflammatory products, increasing anti-inflammatory foods, including the consumption of vegetables and fruits, avoiding white/or red/or processed meat, and avoiding sweets. Nevertheless, diet quality as assessed by the pro-healthy diet index (pHDI-10) and the Mediterranean Diet Score (MDS) showed a low intensity of consumption of pro-healthy food (average pHDI-10 value 31.4%; MDS 7.55/14 points, p = 0.0001). Women with endometriosis reported lower than recommended consumption of fruits, vegetables, dairy products and whole grains. A higher percentage of healthy controls had a "good" level of nutritional knowledge than women with endometriosis. The results of our study highlight the need to improve diet quality and nutritional knowledge among women with endometriosis as well as developing targeted dietary recommendations to help improve well-being and reduce the pain symptoms of endometriosis.

Diet in Prevention and Treatment of Endometriosis: Current State of Knowledge

PURPOSE OF REVIEW

Endometriosis (EM) is a chronic gynecological disease that affects about 10% of women worldwide. It is characterized by the implantation of endometrial cells at ectopic sites. The most common symptom of EM is painful menstruation, which can often lead to chronic pelvic pain that significantly worsens the quality of life. Because some disease-related processes, such as inflammation, hormonal activity, menstrual cycle, or prostaglandin metabolism, can be modified by diet, nutrition may have a significant impact on development and treatment of EM. The purpose of this article was to overview the current knowledge regarding the dietary management of endometriosis.

RECENT FINDINGS

The attention of researchers has so far concentrated mainly on the role of nutrition in the risk of developing EM, while less attention has been paid to examining the use of diet in the treatment of the disease. Current studies focus primarily on various dietary components that have antiproliferative, anti-inflammatory, antioxidant, analgesic, and estrogen-lowering properties. Exploring different ways of coping with endometriosis can make a significant contribution to improving the quality of life of women at risk or diagnosed with EM.

Fructose intake from sugar-sweetened beverages is associated with a greater risk of hyperandrogenism in women: UK Biobank cohort study

OBJECTIVE

To assess the association between fructose consumption and serum sex hormone-binding globulin (SHBG), (free) testosterone, and risk of hyperandrogenism in a population-based cohort.

DESIGN

An observational and genetic association study in participants of the UK Biobank (n = 136 384 and n = 383 392, respectively).

METHODS

We assessed the relationship of (1) the intake of different sources of fructose (ie, total, fruit, fruit juice, and sugar-sweetened beverages [SSBs]) and (2) rs2304681 (a missense variant in the gene encoding ketohexokinase, used as an instrument of impaired fructose metabolism), with SHBG, total and free testosterone levels, and risk of hyperandrogenism (free androgen index >4.5).

RESULTS

The intake of total fructose and fructose from fruit was associated with higher serum SHBG and lower free testosterone in men and women and lower risk of hyperandrogenism in women. In contrast, fructose intake from SSB (≥10 g/day) was associated with lower SHBG in men and women and with higher free testosterone levels and risk of hyperandrogenism in women (odds ratio [OR]: 1.018; 95% confidence interval [CI]: 1.010; 1.026). Carriers of the rs2304681 A allele were characterized by higher circulating SHBG (both men and women), lower serum free testosterone (women), and a lower risk of biochemical hyperandrogenism (OR: 0.997, 95% CI: 0.955; 0.999; women) and acne vulgaris (OR: 0.975, 95% CI: 0.952; 0.999; men and women combined).

CONCLUSIONS

The consumption of ≥10 g/day fructose from SSB, corresponding to ≥200 mL serving, is associated with a 2% higher risk of hyperandrogenism in women. These observational data are supported by our genetic data.

Testosterone, sex hormone-binding globulin and dehydroepiandrosterone levels and cervical length of Egyptian women with a history of recurrent miscarriages, polycystic ovary syndrome and without the conditions at three stages of pregnancy

Total testosterone (TT), sex hormone-binding globulin (SHBG), dehydroepiandrosterone (DHEA) levels, and cervical length (CL) were investigated in pregnant Egyptian women with polycystic ovary syndrome (PCOS, n = 38), history of miscarriages (RM, n = 40) and without the conditions (HC, n = 40). At week 8, the RM had lower levels of TT (p = 0.000) and free androgen index (FAI) (p = 0.000) and higher SHBG (p = 0.000) and DHEA (p < 0.05) than the PCOS. Compared with the HC, they had elevated SHBG (p < 0.05) and DHEA (p = 0.001) and reduced CL (p = 0.000). TT (p = 0.001) and FAI (p = 0.000) were higher and SHBG (p = 0.000) and CL (p = 0.001) lower in the PCOS than in the HC group. At week 16, TT (p = 0.000) and FAI (p = 0.000) were higher, and SHBG (p = 0.000) and CL (p < 0.05) lower in PCOS than in RM and HC. The PCOS had elevated FAI than the RM (p = 0.000) and HC (p = 0.001) at week 20. The DHEA, SHBG and CL abnormalities in PCOS and RM may compromise pregnancy outcomes.IMPACT STATEMENTWhat is already known on this subject? Hyperandrogenaemia, low sex hormone-binding globulin (SHBG), shortened cervical length (CL) and polycystic ovary syndrome (PCOS) are the most cited risk factors for recurrent miscarriages (RM). However, the published data are inconsistent, perhaps because of the confounding effects of ethnicity and nutritional milieu.What do the results of this study add? The study's findings comprising ethnically and socially homogenous women demonstrate that PCOS and RM are characterised by elevated dehydroepiandrosterone (DHEA) and shortened CL, and PCOS by reduced SHBG. These abnormalities would be expected to have an adverse impact on pregnancy outcomes.What are the implications of these findings for clinical practice and/or further research? Twenty-weeks DHEA and CL values have the potential to predict outcome risk in women with a history of RM and PCOS. Further research on other population groups is required to validate the current study's findings.

Aging-related increases in serum sex hormone-binding globulin levels in men might be related to increased synthesis

BACKGROUND

Previous studies have indicated that serum sex hormone-binding globulin (SHBG) levels increase with age; however, the causes remain unknown. The present study aimed to clarify whether the increase in SHBG levels is attributable to aging-related increases in SHBG synthesis.

METHODS

We examined and evaluated the association of serum SHBG levels with synthesis-related factors in men aged 18-80 years. Additionally, we examined the serum and liver levels of SHBG, hepatic nuclear factor 4α (HNF-4α), and peroxisome proliferator-activated receptor γ (PPAR-γ) in young, middle-aged, and old Sprague-Dawley rats.

RESULTS

The study included 209 men in the young group (median age, 33 ± 10 years), 174 men in the middle-aged group (median age, 53 ± 8 years), and 98 men in the elderly group (median age, 71 ± 8 years). Serum SHBG levels increased with age (P < 0.05), whereas HNF-4α and PPAR-γ levels decreased with age (both P < 0.05). Compared with the findings in the young group, the average decline in HNF-4α levels was 2.61 % and 18.46 % in the middle-aged and elderly groups, respectively; the average decreases in PPAR-γ levels in these groups were 12.86 % and 20.76 %, respectively. The results in rats illustrated that liver SHBG and HNF-4α levels increased with age, whereas PPAR-γ and chicken ovalbumin upstream promoter-transcription factor (COUP-TF) levels decreased with age (all P < 0.05). Serum SHBG levels increased in rats with age, whereas HNF-4α and PPAR-γ levels decreased with age (all P < 0.05).

CONCLUSIONS

The aging-related increased liver levels of the SHBG synthesis promoter HNF-4α and decreased levels of the SHBG inhibitory factors PPAR-γ and COUP-TF suggest that the aging-related increases in SHBG levels are associated with increased SHBG synthesis.

The Role of Dietary Fats in the Development and Treatment of Endometriosis

Endometriosis is an estrogen-dependent disease in women of childbearing age that affects approximately 5–15% of the female population. The etiology of endometriosis is complex, multifaceted, and not fully understood. In endometriosis, which is an estrogen-related chronic inflammatory condition, estrogen plays a major role in endometrial cellular growth. High estrogen levels could be another risk factor for developing endometriosis. The aim of this review is to update knowledge on the impact of dietary fats on the development of endometriosis and chronic inflammation in women with endometriosis and diet therapy. Dietary fat may be linked with the progression and development of endometriosis, but studies have been contradictory due to various issues including sample size, different study designs, and different methodological aspects. Results have shown that the risk of endometriosis may increase with a higher consumption of products rich in saturated fats, especially palmitic acid and trans-unsaturated fatty acids. Monounsaturated fats and omega-3 polyunsaturated fatty acids may likely be connected with a lower risk of developing endometriosis and with reductions in the severity of disease. Monounsaturated fats, omega-3 polyunsaturated fatty acids, and a suitable eicosapentaenoic acid to arachidonic acid ratio can be used in diet therapy to improve quality of life by reducing pain and inflammation. Further research is needed in order to fully understand the influence of dietary fats on the risk of development of this disease.

Effect of Sex Hormone-Binding Globulin on Polycystic Ovary Syndrome: Mechanisms, Manifestations, Genetics, and Treatment

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases causing infertility in women of childbearing age. It is characterized by hyperandrogenemia (HA), chronic anovulation, and polycystic ovary morphology (PCOM). Most women with PCOS have metabolic abnormalities. Sex hormone-binding globulin (SHBG), a transport carrier that binds estrogen and androgens and regulates their biological activity, is usually used as an indicator of hyperandrogenism in women with PCOS. Low serum SHBG levels are considered a biomarker of metabolic abnormalities and are associated with insulin resistance (IR), HA, and abnormal glucose and lipid metabolism in PCOS patients. SHBG is also related to the long-term prognosis of PCOS, whereas SHBG gene polymorphism is associated with PCOS risk. In addition, the administration of metformin (MET), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), thiazolidinediones (TZDs), compound oral contraceptives (COCs), as well as nutrient supplements such as inositol (MI), vitamin D, and synbiotics can regulate SHBG levels to ameliorate PCOS complications and improve prognosis. This review focuses on the interaction between SHBG and various PCOS complications as well as the regulation of SHBG by various drugs and nutrients and its therapeutic effects on PCOS.

The Cutoff Value of Low Sex Hormone-Binding Globulin and Its Predictive Role in Impaired Glucose Metabolism Among Chinese Women with Polycystic Ovarian Syndrome

Background: Low levels of sex hormone-binding globulin (SHBG) is a potential predictor of type 2 diabetes mellitus (T2DM), and when combined with insulin resistance (IR), lead to impaired glucose metabolism. Few studies involve women with polycystic ovarian syndrome (PCOS). Studies on cutoff values of SHBG among Asian women were scanty. Methods: The cutoff level of SHBG was computed using the 25th percentile method. Parameters were compared between the lower and higher SHBG subgroup. Area under the curve (AUC) for sensitivity and specificity of SHBG in predicting IR and impaired glucose metabolism was calculated. Results: This study included 733 patients with PCOS 20-45 years of age and 469 age-matched controls. The 25th percentile of SHBG in the control group was 51.90 nM. There were negative correlations between SHBG and age (r = -0.085, P < 0.05), body mass index (BMI) (r = -0.461, P < 0.01), waist-to-hip ratio (WHR) (r = -0.349, P < 0.01), fasting plasma glucose (r = -0.242, P < 0.01), Glucose-1h (r = -0.303, P < 0.01), Glucose-2h (r = -0.336, P < 0.01), fasting insulin (r = -0.324, P < 0.01), Insulin-1h (r = -0.238, P < 0.01), Insulin-2h (r = -0.307, P < 0.01), and homeostasis model 2 assessment of insulin resistance (HOMA2-IR) (r = -0.329, P < 0.01). Age, BMI, WHR, glucose and insulin levels (both pre- and postload), HOMA2-IR, free testosterone, and dehydroepiandrosterone sulfate were all higher in the lower than the higher SHBG subgroup. The AUC of SHBG for predicting IR was 0.706 [95% confidence interval (CI) 0.665-0.745, P < 0.001], impaired fasting glucose was 0.674 (95% CI 0.513-0.838, P < 0.001), impaired glucose tolerance was 0.637 (95% CI 0.586-0.690, P < 0.001), and T2DM was 0.674 (95% CI 0.556-0.780, P < 0.001). Conclusions: A 51.90 nM should be identified as the cutoff value of SHBG. Women with PCOS with lower SHBG values have a higher risk of developing impaired glucose metabolism. Low SHBG should be a predictive biomarker of impaired glucose metabolism in women with PCOS in southern China.

Sex Hormone-Binding Globulin (SHBG) as an Early Biomarker and Therapeutic Target in Polycystic Ovary Syndrome

Human sex hormone-binding globulin (SHBG) is a glycoprotein produced by the liver that binds sex steroids with high affinity and specificity. Clinical observations and reports in the literature have suggested a negative correlation between circulating SHBG levels and markers of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. Decreased SHBG levels increase the bioavailability of androgens, which in turn leads to progression of ovarian pathology, anovulation and the phenotypic characteristics of polycystic ovarian syndrome (PCOS). This review will use a case report to illustrate the inter-relationships between SHBG, NAFLD and PCOS. In particular, we will review the evidence that low hepatic SHBG production may be a key step in the pathogenesis of PCOS. Furthermore, there is emerging evidence that serum SHBG levels may be useful as a diagnostic biomarker and therapeutic target for managing women with PCOS.

Diet and The Risk of Endometriosis in Iranian Women: A Case-Control Study

Background

Endometriosis is one of the most common pelvic diseases associated with dyspareunia, pelvic pain, and infertility. The primary aim of this study is to evaluate the role of diet on the risk of endometriosis among Iranian women.

Materials and Methods

This case-control study was conducted in two health research centres between 2015 and 2016. There were 207 women with endometriosis (case) and 206 women without endometriosis (control) who were evaluated by laparoscopy. The women were asked about their frequency of consumption per week of portions of se- lected dietary items in the Iranian diet in the year before the interview.

Results

The results indicated that intake of green vegetables (odds ratio [OR]=0.39, 95% confidence interval [CI]=0.21–0.74, Ptrend=0.004), red meat (OR=0.61, 95% CI=0.41–0.91, Ptrend=0.015) and dairy products (milk [OR=0.65, 95% CI=0.47–0.92, Ptrend=0.014], cheese [OR=0.53, 95% CI=0.37–0.76, Ptrend<0.001]), fresh fruit (OR=0.68, 95% CI=0.50–0.93, Ptrend=0.015) and grain legumes (OR=0.59, 95% CI=0.47–0.77; Ptrend<0.001) had a significant association with lower risk of endometriosis. Consumption of carrots, green tea, fish, eggs and oil was not significantly related to the risk of endometriosis.

Conclusion

This study suggests that certain types of dietary components may be related to the risk of endometriosis.

Circulating SHBG (Sex Hormone-Binding Globulin) and Risk of Ischemic Stroke: Findings From the WHI

Background and Purpose- Circulating levels of SHBG (sex hormone-binding globulin) have been inversely linked to obesity, diabetes mellitus, and other cardiometabolic disorders. It remains uncertain whether low SHBG is prospectively predictive of stroke risk, particularly in women. We investigated whether SHBG is associated with risk of incident ischemic stroke (IS) among women in the WHI (Women's Health Initiative). Methods- From an observational cohort of 161 808 postmenopausal women enrolled in the WHI at 40 sites across the United States from 1993 to 1998, we identified 13 192 participants free of prevalent stroke at baseline who were included in an ancillary study that measured serum SHBG. We used Cox proportional hazards regression, stratified by SHBG measurement assay, to assess IS risk across quintiles of SHBG (Q1-Q5), adjusting first for demographic variables (model 1), additionally for body mass index, hypertension, alcohol use, and smoking status (model 2), and for physical activity and reproductive risk factors (model 3). In sensitivity analyses, potential mediators (diabetes mellitus status, levels of estradiol, testosterone, and CRP [C-reactive protein]) were included. Results- Of 13 192 participants (mean age, 62.5 years; 67.4% non-Hispanic white, 18.5% black, 7.6% Hispanic, and 5.0% Asian), after following for an average of 11.6 years, 768 IS events were adjudicated. Compared with the highest quintile of SHBG levels (referent), women in the lowest SHBG quintile had a higher risk of IS in all 3 multivariable models (model 1: hazard ratio, 1.88 [95% CI, 1.47-2.41]; model 2: hazard ratio, 1.69 [95% CI, 1.30-2.20]; model 3: hazard ratio, 1.61 [95% CI, 1.19-2.19]; trend tests P<0.05 for all models). Including potential mediators such as diabetes mellitus, estradiol, and testosterone in the models attenuated but did not eliminate significant inverse associations between SHBG and IS. Conclusions- In this prospective cohort of postmenopausal women, there was a statistically significant inverse association between serum SHBG levels and IS risk, which supports the notion that SHBG could be used as a risk stratification tool for predicting IS in women.

The association of food consumption and nutrient intake with endometriosis risk in Iranian women: A case-control study

BACKGROUND

Endometriosis, defined as the attendance of endometrial-like lesions in extra uterine locations, causes pain, infertility, and reduced quality of life.

OBJECTIVE

To evaluate the relationship between food consumption and nutrient intake with risk of endometriosis.

MATERIALS AND METHODS

Of the 156 women approached for the study, 78 women had endometriosis and 78 healthy women were included in the control group. Dietary data were collected using a validated 147-item semi-quantitative Food Frequency Questionnaire (FFQ) with the standard serving size. A logistic regression model was used to determine the association of macronutrients and energy intake with the risk of endometriosis.

RESULTS

In women with higher intake of protein, especially animal protein, monounsaturated fatty acids, soluble and insoluble fiber, oleic acid, eicosapentaenoic acid, and docosahexaenoic acid endometriosis is less common (p< 0.05). High consumption of vegetables, fruits, red meat, yellow vegetables, potatoes, legumes, dairy products, liquid oil, and low intake of fried potatoes was associated with a lower risk of endometriosis (p< 0.05).

CONCLUSION

Regarding the association of dietary intake on endometriosis risk, counseling about improving the dietary structure can contribute toward the prevention and control of endometriosis.

Testosterone-Associated Dietary Pattern Predicts Low Testosterone Levels and Hypogonadism

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