Circulating estrone levels are associated prospectively with diabetes risk in men of the Framingham Heart Study

Testosterone levels and risk of newly diagnosed type 2 diabetes mellitus in adult men: systematic review and meta-analysis

INTRODUCTION

Testosterone is a metabolically active hormone in males for metabolic homeostasis. Although the coexistence of low testosterone levels and type 2 diabetes mellitus (T2DM) have been associated, there are no reports that evaluate alterations in total testosterone (TT) levels and the risk of newly diagnosed T2DM. This review evaluates this question in adult men with high or low levels of total testosterone (TT), as well as the role played by other hormones such as free testosterone (FT), sex hormone binding globulin (SHBG), dihydrotestosterone (DHT), estrogens and testosterone bioavailable (bT).

METHODS

We searched for studies published up to July 30, 2023, in five databases, following a PECO strategy. We found twenty-two studies for quantitative analysis and meta-analyzed the same quantity of studies.

RESULTS

This first meta-analysis incorporates the assessment of the risk of low TT and T2DM in longitudinal studies. 43,038 adult men are included. Our meta-analysis shows that there is an association between low TT levels and the risk of newly diagnosed T2DM (OR 1.52; 95% CI 1.10-2.10; p < 0.05; I²: 79%). It is also evident that SHBG in low TT studies behaves as a risk factor for T2DM in the same way as FT, although without statistical significance. bT behaves as a protective factor. There is no association between estrogen, DHT and T2DM.

CONCLUSIONS

In adult men with low TT values, there is a greater risk of developing a newly diagnosed of T2DM. SHBG values in low TT patients also present a higher risk of T2DM as the same FT but without statistical significance. bT behaves as a protective factor We have not found an association between risk of T2DM and the levels of estrogen, DHT although there are very few studies that report these hormones.

Estrogens and the regulation of glucose metabolism

The main estrogens: estradiol, estrone, and their acyl-esters have been studied essentially related to their classical estrogenic and pharmacologic functions. However, their main effect in the body is probably the sustained control of core energy metabolism. Estrogen nuclear and membrane receptors show an extraordinary flexibility in the modulation of metabolic responses, and largely explain gender and age differences in energy metabolism: part of these mechanisms is already sufficiently known to justify both. With regard to energy, the estrogen molecular species act essentially through four key functions: (1) Facilitation of insulin secretion and control of glucose availability; (2) Modulation of energy partition, favoring the use of lipid as the main energy substrate when more available than carbohydrates; (3) Functional protection through antioxidant mechanisms; and (4) Central effects (largely through neural modulation) on whole body energy management. Analyzing the different actions of estrone, estradiol and their acyl esters, a tentative classification based on structure/effects has been postulated. Either separately or as a group, estrogens provide a comprehensive explanation that not all their quite diverse actions are related solely to specific molecules. As a group, they constitute a powerful synergic action complex. In consequence, estrogens may be considered wardens of energy homeostasis.

D-chiro-inositol, an aromatase down-modulator, increases androgens and reduces estrogens in male volunteers: a pilot study

BACKGROUND

Androgen deficiency affects men in the adulthood, causing several harmful effects at the reproductive and behavioural levels. Since aromatase is an enzyme that catalyses the conversion of androgens to estrogens, and it is responsible for an adequate balance of both sex hormones in males and females, the administration of molecules acting as down modulators may contribute to restore an abnormal enzymatic activity. A prospective pilot study was carried out to investigate the effect of D-chiro-inositol, a putative aromatase down-modulator, on serum levels of testosterone, estradiol, estrone, dehydroepiandrosterone and epiandrosterone from a group of adult male volunteers. Glucose, insulin, follicle-stimulating hormone, luteinizing hormone, inhibin B, D-chiro-inositol and myo-inositol serum levels were also measured.

RESULTS

Male volunteers were selected according to age and body mass index. Subjects with altered glycemia and/or hormonal status, due to advanced age or abnormal weight, were enrolled in the study. Each of the 10 volunteers enrolled took oral D-chiro-inositol (1 g/day) for 1 month. Serum assays of selected markers were performed at baseline (control) and after treatment. D-chiro-inositol administration was associated to reduced serum levels of estrone (- 85.0%) and estradiol (- 14.4%), and increased serum levels of testosterone (+ 23.4%) and dehydroepiandrosterone (+ 13.8%). In addition, epiandrosterone levels were higher (+39%) after treatment. On the other hand, follicle-stimulating hormone, luteinizing hormone and inhibin B did not change. A trend toward a decrease of glycemia, insulinemia and Homeostatic Model Assessment index was observed after D-chiro-inositol treatment, although differences did not reach statistical significance. D-chiro-inositol treatment did not cause any noticeable adverse effect.

CONCLUSIONS

Increased androgens and decreased estrogens seem to confirm that D-chiro-inositol acts as an aromatase down-modulator, but with a still unknown mechanism of action. This pilot study opens up new perspectives of research and therapeutic applications for D-chiro-inositol at different dosages and length of treatment. Authorization number 005/2020 released by the Local Ethics Committee of Alma Res Fertility Center, Rome.

TRIAL REGISTRATION NUMBER

NCT04615767 (registry: ClinicalTrials.gov) Date of registration: November 3, 2020.

Pro-social and anxiolytic-like behavior following a single 24-h exposure to 17β-estradiol in adult male zebrafish

Estradiol (17β-estradiol, E₂) is a crucial estrogen hormone that regulates sexual, cognitive, social and affective behaviors in various species. However, complex central nervous system (CNS) effects of E₂, including its activity in males, remain poorly understood. The zebrafish (Danio rerio) is rapidly becoming a powerful novel model system in translational neuroscience research. Here, we evaluate the effects of a single 24-h exposure to 20 μg/L of E₂ on behavioral and endocrine (cortisol) responses in adult male zebrafish. Overall, E₂ exerted pro-social effect in the social preference test, reduced whole-body cortisol levels, elevated exploration in the novel tank test and increased the shoal size in the shoaling test, indicative of an anxiolytic-like profile of this hormone in male zebrafish. Supporting mounting human and rodent evidence on the role of E₂ in behavioral regulation, the observed pro-social and anxiolytic-like effects of E₂ in male zebrafish reinforce the use of this aquatic organism in studying steroid-mediated CNS mechanisms of complex affective and social behaviors.

LCMS Measurement of Steroid Biomarkers Collected from Palmar Sweat

Human eccrine sweat contains numerous biomarkers which can provide information on health, performance, and aging. Non-invasive collection and measurement of biomarkers has become especially important in recent times given viral outbreaks like SARS-CoV-2. In the current study we describe a method of sweat collection from palmar surfaces in participants via surface capture using glass beads and the resulting analysis of biomarkers from very low volumes of sweat using liquid chromatography mass spectrometry with selected ion monitoring. Study participants underwent a cognitive and physical stress task with easy and hard conditions with sweat being collected after each task. Resulting analysis found a signal for 22 steroid biomarkers and we report detailed information on selected biomarkers, given their applicability to timely real-world exemplars, including cortisol, dehydroepiandrosterone, allopregnanolone, estrone, aldosterone, and 20α/β-dihydrocortisone.

Development of Classification Models for the Prediction of Alzheimer's Disease Utilizing Circulating Sex Hormone Ratios

BACKGROUND

While sex hormones are essential for normal cognitive health, those individuals with greater endocrine dyscrasia around menopause and with andropause are more likely to develop cognitive loss and Alzheimer's disease (AD).

OBJECTIVE

To assess whether circulating sex hormones may provide an etiologically significant, surrogate biomarker, for cognitive decline.

METHODS

Plasma (n = 152) and serum (n = 107) samples from age- and gender-matched AD and control subjects from the Wisconsin Alzheimer's Disease Research Center (ADRC) were analyzed for 11 steroids and follicle-stimulating hormone. Logistic regression (LR), correlation analyses, and recursive partitioning (RP) were used to examine the interactions of hormones and hormone ratios and their association with AD. Models generated were then tested on an additional 43 ADRC samples.

RESULTS

The wide variation and substantial overlap in the concentrations of all circulating sex steroids across control and AD groups precluded their use for predicting AD. Classification tree analyses (RP) revealed interactions among single hormones and hormone ratios that associated with AD status, the most predictive including only the hormone ratios identified by LR. The strongest associations were observed between cortisol, cortisone, and androstenedione with AD, with contributions from progesterone and 17β-estradiol. Utilizing this model, we correctly predicted 81% of AD test cases and 64% of control test cases.

CONCLUSION

We have developed a diagnostic model for AD, the Wisconsin Hormone Algorithm Test for Cognition (WHAT-Cog), that utilizes classification tree analyses of hormone ratios. Further refinement of this technology could provide a quick and cheap diagnostic method for screening those with AD.

Correlation between glucose metabolism and serum steroid hormones in patients with polycystic ovary syndrome

OBJECTIVE

Polycystic ovary syndrome (PCOS) is associated with an increased prevalence of dysglycaemia, which includes impaired glucose tolerance and type 2 diabetes mellitus (T2DM). Patients with PCOS demonstrate abnormal patterns of steroid hormones. Here, we analyse the correlation between glucose metabolism and serum steroid hormones in PCOS.

DESIGN

Observational double-centre study.

PATIENTS

914 patients with PCOS.

MEASUREMENTS

We assessed the glucose metabolism status of all patients according to the 1999 WHO criteria. Serum steroid hormones were measured by liquid chromatography-tandem mass spectrometry.

RESULTS

The median age of the patients was 26 years (interquartile range: 21-30), and 40.6% (371/914) had abnormal glucose metabolism: 29.3% (268/914) had prediabetes, and 11.3% (103/914) had T2DM. Correlation analysis not adjusting for confounding factors revealed that serum aldosterone, androstenedione, oestrone, pregnenolone and the free androgen index were positively correlated, while progesterone was negatively correlated with the risk of abnormal glucose metabolism. After adjusting for age, body mass index and fasting insulin levels in the logistic regression model, only aldosterone (P = .013), androstenedione (P = .046) and oestrone (P = .014; in quartiles) were correlated with the risk of abnormal glucose metabolism.

CONCLUSIONS

This study indicates a high prevalence of prediabetes and T2DM in patients with PCOS. Furthermore, there were positive correlations of serum aldosterone, androstenedione and oestrone with the risk of abnormal glucose metabolism after adjusting for confounding factors.

The Exercise, Arterial Modulation and Nutrition in Youth South Africa Study (ExAMIN Youth SA)

Background: The impact of a sedentary and unhealthy lifestyle on cardiovascular health is well-documented, however the current obesity and hypertension trends among children is concerning. The ExAMIN Youth SA study aims to investigate the impact of lifestyle behaviors (physical fitness/activity, dietary intake and psychosocial factors) involved in early vascular aging among South African children. Methods: This study is an analytical, multidisciplinary, observational cohort study in a school-based setting. We aim to phenotype a cohort of ~1,000 primary school children (black and white boys and girls between ages 5-9 years) based on current clinical childhood conditions including hypertension and obesity. The primary phenotype is large artery stiffness and retinal microvascular diameters, both biomarkers of early vascular aging. The risk factors and mediators of early vascular aging and also responsible for the clinical conditions include physical inactivity, unhealthy diet, and life stress. Additionally, urinalysis and salivary analyses will be performed to identify biomarkers related to the pathophysiology of early vascular aging. Discussion: In line with the growing prevalence of obesity and hypertension responsible for the development of early vascular aging from childhood to adulthood, this study will address the critical areas in which we observe unfavorable arterial modulation related to dietary behaviors, physical inactivity, and early life stress. Implementation of novel biological markers may further contribute to our understanding of early cardiovascular adaptations in childhood, and aid in the development of primary prevention programs. Trial registration: The study was retrospectively registered on ClinicalTrials.gov on 15 August 2019 (NCT04056377).

Aging and the Male Reproductive System

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

Measuring estrogens in women, men, and children: Recent advances 2012-2017

The measurement of estrogens is important for diagnosing and monitoring the health of women, men, and children. For example, for postmenopausal women or women undergoing treatment for breast cancer with aromatase inhibitors, the measurement of extremely low concentrations of estrogens in serum, especially estradiol, is problematic but essential for proper medical care. Achieving superb analytical sensitivity and specificity has been and continues to be a challenge for the clinical laboratory, but is a challenge that is being taken seriously. Focusing on publications from 2012 to 2017, this review will provide an overview of recent research in the development of methods to accurately and precisely measure estrogens, including a variety of estrogen metabolites. Additionally, the latest in clinical research involving estrogen measurement in women, men, and children will be presented to provide an update on the association of estrogens with diseases or conditions such as breast cancer, precocious puberty, infertility, and pregnancy. This research update will provide context as to why estrogen measurement is important and why laboratories are working hard to support the recommendations made by the Endocrine Society regarding estrogen measurement.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Circulating Estrogen Levels and Self-Reported Health and Mobility Limitation in Community-Dwelling Men of the Framingham Heart Study

Background

Self-rated health is a commonly used global indicator of health status. Few studies have examined the association of self-rated health and mobility with estrone and estradiol in men. Accordingly, we determined the cross-sectional, incident, and mediating relations between circulating estrone and estradiol levels with self-rated health, mobility limitation, and physical performance in community-dwelling men.

Methods

The cross-sectional sample included 1,148 men, who attended Framingham Offspring Study Examinations 7 and 8. Estrone and estradiol levels were measured using liquid chromatography tandem mass spectrometry at Examination 7. Self-reported mobility limitation and self-rated health were assessed at Examinations 7 and 8. Additionally, short physical performance battery, usual walking speed, and grip strength were assessed at Examination 7.

Results

In incident analysis, estradiol levels at Examination 7 were associated with increased odds of fair or poor self-rated health at Examination 8, after adjusting for age, body mass index, comorbidities, and testosterone levels; in an individual with 50% greater estradiol than other, the odds of reporting "fair or poor" self-rated health increased by 1.78 (95% confidence interval: 1.25-2.55; p = .001). Neither estrone nor estradiol levels were associated with any physical performance measure at baseline.

Conclusions

Higher circulating levels of estradiol are associated with increased risk of incident fair/poor self-rated health in community-dwelling men. The mechanisms by which circulating levels of estradiol are related to self-rated health in men need further investigation.

Estrogens and Body Weight Regulation in Men

Our understanding of the metabolic roles of sex steroids in men has evolved substantially over recent decades. Whereas testosterone once was believed to contribute to metabolic risk in men, the importance of adequate androgen exposure for the maintenance of metabolic health has been demonstrated unequivocally. A growing body of evidence now also supports a critical role for estrogens in metabolic regulation in men. Recent data from clinical intervention studies indicate that estradiol may be a stronger determinant of adiposity than testosterone in men, and even short-term estradiol deprivation contributes to fat mass accrual. The following chapter will outline findings to date regarding the mechanisms, whereby estrogens contribute to the regulation of body weight and adiposity in men. It will present emergent clinical data as well as preclinical findings that reveal mechanistic insights into estrogen-mediated regulation of body composition. Findings in both males and females will be reviewed, to draw comparisons and to highlight knowledge gaps regarding estrogen action specifically in males. Finally, the clinical relevance of estrogen exposure in men will be discussed, particularly in the context of a rising global prevalence of obesity and expanding clinical use of sex steroid-based therapies in men.

Combined effects of sex hormone-binding globulin and sex hormones on risk of incident type 2 diabetes

BACKGROUND

The aim of the present study was to investigate the combined effects of sex hormone-binding globulin (SHBG) and sex hormones on the risk of type 2 diabetes (T2D).

METHODS

A nested case-control study of Chinese participants in the Environment, Inflammation and Metabolic Diseases Study (2008-13) was performed. Of the 3510 subjects free of diabetes, 145 men and 87 women developed diabetes over the 5-year follow-up. One age- and sex-matched control subject was selected for each case. Baseline concentrations of SHBG, estradiol, testosterone, and dehydroepiandrosterone sulfate (DHEA-S) were divided into tertiles and subjects were classified as having low, intermediate and high levels accordingly.

RESULTS

After multivariate adjustment, men with low SHBG levels had a fourfold greater risk of T2D than men with high SHBG levels. Conversely, men with high estradiol levels had a fourfold greater risk of T2D than men with low estradiol levels. Men with low SHBG + high estradiol had a 20-fold greater risk of T2D than men with high SHBG + low estradiol (odds ratio [OR] 20.23; 95% confidence interval [CI] 4.62-51.33). These risk associations in men were not observed for testosterone or DHEA-S, alone or in combination with SHBG. Compared with low SHBG, the risk of T2D decreased with increasing SHBG tertile (OR 0.92 [95% CI 0.21-4.53], 0.14 [95% CI 0.10-0.74]; Ptrend  = 0.043) after multivariate adjustment in women. Estradiol, testosterone, and DHEA-S levels showed no association with T2D in women.

CONCLUSION

Low SHBG in conjunction with high estradiol has an additive detrimental effect on the risk of T2D in men.

Circulating Sex Steroids and Vascular Calcification in Community-Dwelling Men: The Framingham Heart Study

CONTEXT

The relationship between sex steroids and atherosclerosis is poorly understood.

OBJECTIVE

To describe the association of serum total T (TT), calculated free T (cFT), estrone (E1), estradiol (E2), and SHBG to vascular calcification in adult men.

DESIGN

Observational study (Framingham Heart Study). Analyses are cross-sectional. TT, E1, and E2 were measured by liquid chromatography-tandem mass spectrometry, and SHBG by immunofluorometric assay. Estimates of association were obtained by Tobit regression, which acknowledges the influence of floor effects on outcomes.

SETTING

General community.

PARTICIPANTS

A total of 1654 community-dwelling men from the Offspring and Third Generation cohorts of the Framingham Heart Study.

MAIN OUTCOME MEASURES

Coronary artery calcification (CAC), abdominal aortic calcification, and thoracic aortic calcification were measured by computed tomography.

RESULTS

Mean (standard deviation [SD]) age was 49 (10) years. Mean (SD) TT, cFT, and SHBG were: 616 (224) ng/dL, 111 (45) pg/mL, and 46 (23) nmol/L, respectively. Mean (SD) E2 and E1 were 28 (10) and 39 (14) pg/mL. Vascular calcification at all sites was negatively associated with TT and cFT and positively associated with E2 and E1. A 100-ng/dL between-subjects increase in TT was associated with a mean (95% confidence interval) age-adjusted difference in CAC of -23% (-41%, -4%) (P = .02). After model adjustment for other cardiovascular risk factors, the estimated associations between T and vascular calcification scores were statistically nonsignificant.

CONCLUSIONS

Decreased circulating T and E2 levels are associated with an age-adjusted increase in CAC, but these associations appear to express relationships either attributable to or mediated by established cardiovascular risk factors.

Sex steroids and glucose metabolism

Testosterone levels are lower in men with metabolic syndrome and type 2 diabetes mellitus (T2DM) and also predict the onset of these adverse metabolic states. Body composition (body mass index, waist circumference) is an important mediator of this relationship. Sex hormone binding globulin is also inversely associated with insulin resistance and T2DM but the data regarding estrogen are inconsistent. Clinical models of androgen deficiency including Klinefelter's syndrome and androgen deprivation therapy in the treatment of advanced prostate cancer confirm the association between androgens and glucose status. Experimental manipulation of the insulin/glucose milieu and suppression of endogenous testicular function suggests the relationship between androgens and insulin sensitivity is bidirectional. Androgen therapy in men without diabetes is not able to differentiate the effect on insulin resistance from that on fat mass, in particular visceral adiposity. Similarly, several small clinical studies have examined the efficacy of exogenous testosterone in men with T2DM, however, the role of androgens, independent of body composition, in modifying insulin resistance is uncertain.

Androgen deficiency and type 2 diabetes mellitus

The rising incidence of T2DM is well recognised and associated with trends in obesity and ageing. It is estimated that 2.8% of the world population had a diagnosis of diabetes mellitus in 2000, which is projected to rise to 4.3% by 2030. Diabetes, obesity and ageing are also associated with an increased risk of isolated male hypogonadotropic hypogonadism, often labelled 'late onset hypogonadism' (LOH) to distinguish it from hypogonadism secondary to distinct hypothalamopituitary pathology. Whether the incidence of hypogonadism is increasing is open to question; the past decade, however, has witnessed a marked increase in the prescription of testosterone replacement therapy. Testosterone deficiency appears to be particularly common in type 2 diabetes with a prevalence of 33% observed in one cohort of 103 men (mean age 54.7). However, the diagnosis of androgen deficiency states is not necessarily straightforward, depending amongst other factors, upon whether a biochemical threshold or a syndromic approach (mandating the presence of certain key clinical features) is employed. The pathogenic mechanisms underlying obesity and diabetes related hypogonadism remain unclear with several competing theories, most of which are not mutually exclusive. Whilst a large body of epidemiological evidence associates testosterone deficiency with increased risk of cardiovascular disease and mortality, little evidence exists to support a protective effect of testosterone replacement. The benefits of androgen replacement in younger men with pituitary disease are well established, however, the potential benefits and safety of androgen replacement in older men is much less well developed. At present, replacement therapy in older men is advocated principally for the amelioration of sexual symptoms. This review will seek to explore issues around the pathogenesis, diagnosis, clinical consequences and management of male hypogonadism as it relates to T2DM.

Advanced glycation endproducts in diabetes and diabetic complications

This review presents insights from studies of advanced glycation end products (AGEs) in humans and mice. Although the emphasis is on the effects of exogenous AGEs and the suppression of specific host defense mechanisms, AGEs are also formed intracellularly, where they may contribute to several normal intracellular functions. It is only when the overall levels of AGEs in the extracellular and the intracellular spaces exceeds the ability of the native antioxidant (and AGE) defenses that they pose a problem.