Contribution of body fatness and adipose tissue distribution to the age variation in plasma steroid hormone concentrations in men: the HERITAGE Family Study

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

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

Associations between sex hormones and metabolic-associated fatty liver disease in a middle-aged and elderly community

Metabolic-associated fatty liver disease (MAFLD) was proposed by an international expert consensus to replace non-alcoholic fatty liver disease (NAFLD) in 2020. Previous studies have shown that sex hormones are strongly linked to NAFLD development. This study aims to explore whether sex hormones are associated with MAFLD and liver fat content (LFC) in a middle-aged and elderly community. The study included 732 subjects aged 50-80 years enrolled from communities. MAFLD was diagnosed using the 2020 International Expert Consensus. LFC was calculated using parameters from abdominal ultrasound images. Serum estradiol (E2), total testosterone (TT), sex hormone-binding globulin (SHBG), FSH, and LH were measured by chemiluminescent microparticle immunoassay. MAFLD was diagnosed in 107/304 (35.2%) men and 154/428 (35.2%) women. After adjustments for confounding factors, logistic regression analysis showed that SHBG was negatively correlated with MAFLD in men (OR, 0.95 [0.93-0.97], p < 0.001). In women, SHBG and FSH were negatively correlated with MAFLD (OR, 0.95 [0.94-0.97], p < 0.001; OR, 0.97 [0.96-0.98], p < 0.001). Multivariate linear regression analysis showed that SHBG was a negative factor for LFC in both men (standardized β = -0.188, p < 0.001) and women (standardized β = -0.184, p < 0.001). FSH was a negative factor for LFC in women (standardized β = -0.082, p = 0.046). SHBG was negatively correlated with MAFLD in middle-aged and elderly men and women. Moreover, FSH was negatively correlated, and bioactive testosterone was positively correlated with MAFLD in women. These findings suggest a relationship between sex hormones and MAFLD.

The HERITAGE Family Study: A Review of the Effects of Exercise Training on Cardiometabolic Health, with Insights into Molecular Transducers

The aim of the HERITAGE Family Study was to investigate individual differences in response to a standardized endurance exercise program, the role of familial aggregation, and the genetics of response levels of cardiorespiratory fitness and cardiovascular disease and diabetes risk factors. Here we summarize the findings and their potential implications for cardiometabolic health and cardiorespiratory fitness. It begins with overviews of background and planning, recruitment, testing and exercise program protocol, quality control measures, and other relevant organizational issues. A summary of findings is then provided on cardiorespiratory fitness, exercise hemodynamics, insulin and glucose metabolism, lipid and lipoprotein profiles, adiposity and abdominal visceral fat, blood levels of steroids and other hormones, markers of oxidative stress, skeletal muscle morphology and metabolic indicators, and resting metabolic rate. These summaries document the extent of the individual differences in response to a standardized and fully monitored endurance exercise program and document the importance of familial aggregation and heritability level for exercise response traits. Findings from genomic markers, muscle gene expression studies, and proteomic and metabolomics explorations are reviewed, along with lessons learned from a bioinformatics-driven analysis pipeline. The new opportunities being pursued in integrative -omics and physiology have extended considerably the expected life of HERITAGE and are being discussed in relation to the original conceptual model of the study.

Obesity as a premature aging phenotype - implications for sarcopenic obesity

Obesity and aging have both seen dramatic increases in prevalence throughout society. This review seeks to highlight common pathologies that present with obesity, along with the underlying risk factors, that have remarkable similarity to what is observed in the aged. These include skeletal muscle dysfunction (loss of quantity and quality), significant increases in adiposity, systemic alterations to autonomic dysfunction, reduction in nitric oxide bioavailability, increases in oxidant stress and inflammation, dysregulation of glucose homeostasis, and mitochondrial dysfunction. This review is organized by the aforementioned indices and succinctly highlights literature that demonstrates similarities between the aged and obese phenotypes in both human and animal models. As aging is an inevitability and obesity prevalence is unlikely to significantly decrease in the near future, these two phenotypes will ultimately combine as a multidimensional syndrome (a pathology termed sarcopenic obesity). Whether the pre-mature aging indices accompanying obesity are additive or synergistic upon entering aging is not yet well defined, but the goal of this review is to illustrate the potential consequences of a double aged phenotype in sarcopenic obesity. Clinically, the modifiable risk factors could be targeted specifically in obesity to allow for increased health span in the aged and sarcopenic obese populations.

Non-alcoholic Steatohepatitis: From Pathophysiology to Clinical Practice

Non-alcoholic steatohepatitis (NASH) is becoming a global disease with significant associated comorbidities. To date, there are no commercialized drugs to treat NASH, outside of India; however, there is an abundance of new molecular entities which are in clinical development, some in phase III trials. Many of these trials have created an especially heavy demand for USA-based subjects. Hepatologists currently play a major role in the diagnosis, treatment and clinical-trial enrolment of patients with NASH. However, NASH has a strong metabolic component, with patients often carrying comorbid diseases, such as type 2 diabetes mellitus, obesity, hyperlipidaemia, hypothyroidism and sex steroid disorders. The primary care physician, internist and endocrinologist stand at a pivotal position in the NASH healthcare delivery system, as many of the diseases they commonly encounter are associated with a higher risk of developing NASH. Specialty society practice guidelines are evolving regarding the identification and care of patients with NASH. This review of the literature, and assessment of IQVIA's proprietary patient claims database of diagnosis codes, patient encounters and treatments, substantiates the importance of the primary care provider and endocrinologist in the clinical care and clinical research of patients with NASH.

The beneficial effect of glycerophosphocholine to local fat accumulation: a comparative study with phosphatidylcholine and aminophylline

Injection lipolysis or mesotherapy gained popularity for local fat dissolve as an alternative to surgical liposuction. Phosphatidylcholine (PPC) and aminophylline (AMPL) are commonly used compounds for mesotherapy, but their efficacy and safety as lipolytic agents have been controversial. Glycerophosphocholine (GPC) is a choline precursor structurally similar to PPC, and thus introduced in aesthetics as an alternative for PPC. This study aimed to evaluate the effects of GPC on adipocytes differentiation and lipolysis and compared those effects with PPC and AMPL using in vitro and in vivo models. Adipogenesis in 3T3-L1 was measured by Oil Red O staining. Lipolysis was assessed by measuring the amount of glycerol released in the culture media. To evaluate the lipolytic activity of GPC on a physiological condition, GPC was subcutaneously injected to one side of inguinal fat pads for 3 days. Lipolytic activity of GPC was assessed by hematoxylin and eosin staining in adipose tissue. GPC significantly suppressed adipocyte differentiation of 3T3-L1 in a concentration-dependent manner (22.3% inhibition at 4 mM of GPC compared to control). Moreover, when lipolysis was assessed by glycerol release in 3T3-L1 adipocytes, 6 mM of GPC stimulated glycerol release by two-fold over control. Subcutaneous injection of GPC into the inguinal fat pad of mice significantly reduced the mass of fat pad and the size of adipocytes of injected site, and these effects of GPC were more prominent over PPC and AMPL. Taken together, these results suggest that GPC is the potential therapeutic agent as a local fat reducer.

Sex differences in vascular aging in response to testosterone

Large elastic arterial stiffening and endothelial dysfunction are phenotypic characteristics of vascular aging, a major risk factor for age-associated cardiovascular diseases. Compared to men, vascular aging in women appears to be slowed until menopause, whereafter vascular aging accelerates to match that seen in men. These sex differences in vascular aging have been attributed to changes in sex hormones that occur with aging. Although the role of estradiol in vascular aging in women has been highlighted in recent aging research, little is known about the impact of declining testosterone concentrations in both sexes. Importantly, while androgen concentrations generally decline with age in men, there are data that indicate reductions in androgen concentrations in women as well. Evidence suggests that low testosterone is associated with impaired endothelial function and increased arterial stiffness in men, although the effect of androgens on vascular aging in women remains unclear. Testosterone may modulate vascular aging by mitigating the effects of oxidative stress and inflammation, although there is sex specificity to this effect. The purpose of this review is to present and summarize the research regarding sex differences in vascular aging in response to androgens, specifically testosterone. Because exercise is a potent lifestyle factor for slowing and reversing vascular aging, we briefly summarize the available literature regarding the regulatory function of testosterone on vascular adaptations to exercise training.

Secondary male hypogonadism: A prevalent but overlooked comorbidity of obesity

Male hypogonadism associated with obesity is a very prevalent condition and is increasing in parallel with the epidemic prevalence of obesity. Low testosterone levels promote higher fat mass with reduced lean mass. Male hypogonadism is related to an increase in associated cardiometabolic complications, such as hypertension, type 2 diabetes mellitus, the metabolic syndrome, and cardiovascular disease. Its influence as a comorbidity of obesity is becoming more evident and should be evaluated and treated in at-risk patients. Mechanisms involved in this relationship include body composition changes, the presence of adipokines, insulin resistance, and other factors, some of which are still unknown. Weight loss and treatment to replace testosterone levels improve the metabolic profile and quality of life in patients with obesity and hypogonadism; these beneficial effects depend on treatment modality and duration of therapy. The use of testosterone replacement therapy may be indicated, as it has not been shown to increase cardiovascular risk, and retrospective studies suggest a reduction in events in men with metabolic syndrome and type 2 diabetes.

Metabolic Disorders and Male Hypogonadotropic Hypogonadism

Several studies highlight that testosterone deficiency is associated with, and predicts, an increased risk of developing metabolic disorders, and, on the other hand, is highly prevalent in obesity, metabolic syndrome and type-2 diabetes mellitus. Models of gonadotropin releasing hormone deficiency, and androgen deprivation therapy in patients with prostate cancer, suggest that hypogonadotropic hypogonadism might contribute to the onset or worsening of metabolic conditions, by increasing visceral adiposity and insulin resistance. Nevertheless, in functional hypogonadism, as well as in late onset hypogonadism, the relationship between hypogonadotropic hypogonadism and metabolic disorders is bidirectional, and a vicious circle between the two components has been documented. The mechanisms underlying the crosstalk between testosterone deficiency and metabolic disorders include increased visceral adipose tissue and insulin resistance, leading to development of metabolic disorders, which in turn contribute to a further reduction of testosterone levels. The decrease in testosterone levels might be determined by insulin resistance-mediated and, possibly, pro-inflammatory cytokine-mediated decrease of sex hormone binding globulin, resulting in a temporary increased free testosterone available for aromatization to estradiol in visceral adipose tissue, followed by a subsequent decrease in free testosterone levels, due to the excess of visceral adipose tissue and aromatization; by a direct inhibitory effect of increased leptin levels on Leydig cells; and by a reduced gonadotropin secretion induced by estradiol, inflammatory mediators, leptin resistance, and insulin resistance, with the ultimate determination of a substantial hypogonadotropic hypogonadism. The majority of studies focusing on the effects of testosterone replacement therapy on metabolic profile reported a beneficial effect of testosterone on body weight, waist circumference, body mass index, body composition, cholesterol levels, and glycemic control. Consistently, several interventional studies demonstrated that correction of metabolic disorders, in particular with compounds displaying a greater impact on body weight and insulin resistance, improved testosterone levels. The aim of the current review is to provide a comprehensive overview on the relationship between hypogonadotropic hypogonadism and metabolism, by clarifying the independent role of testosterone deficiency in the pathogenesis of metabolic disorders, and by describing the relative role of testosterone deficiency and metabolic impairment, in the context of the bidirectional relationship between hypogonadism and metabolic diseases documented in functional hypogonadotropic hypogonadism. These aspects will be assessed by describing metabolic profile in men with hypogonadotropic hypogonadism, and androgenic status in men with metabolic disorders; afterwards, the reciprocal effects of testosterone replacement therapy and corrective interventions on metabolic derangements will be reported.

Age-related changes in estradiol and longitudinal associations with fat mass in men

Context

In men, circulating 17β-estradiol originates primarily from peripheral aromatization of testosterone particularly in adipose tissue. The effect of ageing and obesity on circulating estradiol remains unclear.

Objective

Determine five-year changes in serum estradiol and the association with testosterone and fat mass in Australian men.

Design

Longitudinal cohort study. At baseline and five-year follow-up, socio-demographic and health-related data including behaviors, chronic conditions, and medication use were collected by questionnaire. Estradiol and testosterone were assayed by liquid chromatography-tandem mass spectrometry and sex hormone-binding globulin by immunochemiluminescent assay. Fat mass was assessed by dual-energy X-ray absorptiometry.

Participants

Community-dwelling men aged 35 years and older at enrollment, resident in the northern and western suburbs of Adelaide without established disease of, or medications affecting, the hypothalamus-pituitary-gonadal axis (n = 725).

Main outcome measures

The dependence of change in serum estradiol over five years on age, testosterone and fat mass after adjustment for multiple confounders.

Results

At baseline, mean age was 53.0 ± 10.8 years. Mean serum estradiol levels at baseline and five-year follow-up were 94.9 ± 34.8 and 89.4 ± 30.4 pmol/L respectively (-1.1 pmol/L/year). On multivariable analyses, estradiol change was associated with changes in testosterone (B-estimate = 2.719, standard error = 0.369, p˂0.001), but not age or total fat mass. Change in testosterone/estradiol ratio was inversely associated with change in fat mass (B = -1.450, SE = 0.575, p = 0.012), and this was consistent across quartiles of fat mass change.

Conclusions

In healthy men, circulating estradiol is primarily dependent on testosterone. With increasing fat mass, estradiol decreases less than testosterone. From a clinical standpoint these data indicate that obesity is associated with a change in the testosterone to estradiol ratio, but a change in estradiol does not occur unless some other pathology is present.

MECHANISMS IN ENDOCRINOLOGY: The sexually dimorphic role of androgens in human metabolic disease

Female androgen excess and male androgen deficiency manifest with an overlapping adverse metabolic phenotype, including abdominal obesity, insulin resistance, type 2 diabetes mellitus, non-alcoholic fatty liver disease and an increased risk of cardiovascular disease. Here, we review the impact of androgens on metabolic target tissues in an attempt to unravel the complex mechanistic links with metabolic dysfunction; we also evaluate clinical studies examining the associations between metabolic disease and disorders of androgen metabolism in men and women. We conceptualise that an equilibrium between androgen effects on adipose tissue and skeletal muscle underpins the metabolic phenotype observed in female androgen excess and male androgen deficiency. Androgens induce adipose tissue dysfunction, with effects on lipid metabolism, insulin resistance and fat mass expansion, while anabolic effects on skeletal muscle may confer metabolic benefits. We hypothesise that serum androgen concentrations observed in female androgen excess and male hypogonadism are metabolically disadvantageous, promoting adipose and liver lipid accumulation, central fat mass expansion and insulin resistance.

Body composition changes in male patients with chronic obstructive pulmonary disease: Aging or disease process?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) mainly affects middle-age and elderly adults. It is unclear if the presence of muscle wasting and fat accumulation in patients with COPD is age or disease-related. This study investigated the effect of age and COPD disease severity on body composition with the aim of identifying a biomarker(s) for COPD.

METHODS

Healthy subjects and patients with COPD of different severity were recruited. Dual-energy X-ray absorptiometry was used to analyze total and segmental body composition. Subjects included in the analysis were classified into four groups: healthy young (aged 20-45 years) (n = 35), healthy old (aged ≥ 60 years) (n = 37), moderate COPD (n = 40), and severe COPD (n = 14).

RESULTS

In healthy old adults, leg and limb lean masses were lower by 10.6% and 8.5%, respectively, compared with healthy young adults (P < 0.05). Appendicular lean outcomes were significantly lower in the moderate COPD compared to the healthy old group and were significant lower in subjects with severe COPD compared to those with moderate COPD. All fat depots were similar for both young and old healthy subjects and subjects with moderate COPD, but significantly decreased in patients with severe COPD.

CONCLUSIONS

This study examined the changes in total and segmental body composition with aging and COPD severity. It found that aging and COPD altered the body composition differently, and the effect was most pronounced in leg lean mass. Remarkably, differences in appendicular lean masses were seen in mild COPD although no changes in body weight or BMI were apparent compared with healthy young adults. In contrast, fat depot changes were only observed in severe COPD. Aging and COPD processes are multifactorial and additional longitudinal studies are required to explore both the quantitative and qualitative changes in body composition with aging and disease process.

The differing influence of several factors on the development of fatty liver with elevation of liver enzymes between genders with metabolic syndrome: A cross-sectional study

Background

Nonalcoholic fatty liver disease (NAFLD) is known to be strongly associated with obesity, visceral fat, metabolic syndrome (MS), lifestyle, and lifestyle-related diseases in both males and females. However, the prevalence of NAFLD, MS, and clinical backgrounds is different between males and females.

Objective

We conducted a cross-sectional study to examine the differing influence of lifestyle-related factors and visceral fat on fatty liver (FL) with elevation of liver enzymes between males and females with MS.

Methods

We enrolled 42,134 persons who underwent a regular health check-up, and after excluding subjects who fulfilled excluding criteria, the remaining subjects were 2,110 persons with MS. We examined the differing influence of lifestyle-related factors and visceral fat on FL with elevation of alanine aminotransferase (ALT) (ALT elevation was defined as ALT level of ≥31 IU/l in the present study).

Results

The odds rations for FL with ALT elevation were as follows: WC, 1.83 (95% confidence interval (CI) 1.36–2.46); dyslipidemia, 1.89 (95% CI 1.34–2.68); hemoglobin A1c, 1.36 (95% CI 1.00–1.85); visceral fat type MS (V-type MS), 5.78 (95% CI 4.29–7.80); and light drinker, 0.56 (95% CI 0.41–0.78) in males with MS and BMI, 2.18 (95% CI 1.43–3.33); WC, 1.85 (95% CI 1.27–2.70); diastolic blood pressure, 1.69 (95% CI 1.16–2.45); triglyceride, 2.22 (95% CI 1.56–3.17); impaired glucose tolerance, 1.66 (95% CI 1.11–2.47); and V-type MS, 3.83 (95% CI 2.57–5.70) in females with MS. The prevalence of FL with ALT elevation and ALT was significantly higher in V-type MS than in the subcutaneous fat type MS in both males and females with MS (P < 0.001).

Conclusion

Although V-type MS and WC is a common significant predictor of an increased prevalence of FL with ALT elevation in both males and females with MS, gender, lifestyle-related factors, and MS type in individuals with MS should be considered for the development of FL with ALT elevation.

Sex hormones and macronutrient metabolism

The biological differences between males and females are determined by a different set of genes and by a different reactivity to environmental stimuli, including the diet, in general. These differences are further emphasized and driven by the exposure to a different hormone flux throughout the life.

These differences have not been taken into appropriate consideration by the scientific community. Nutritional sciences are not immune from this “bias” and when nutritional needs are concerned, females are considered only when pregnant, lactating or when their hormonal profile is returning back to “normal,” i.e., to the male-like profile.

The authors highlight some of the most evident differences in aspects of biology that are associated with nutrition.

This review presents and describes available data addressing differences and similarities of the “reference man” vs. the “reference woman” in term of metabolic activity and nutritional needs. According to this assumption, available evidences of sex-associated differences of specific biochemical pathways involved in substrate metabolism are reported and discussed. The modulation by sexual hormones affecting glucose, amino acid and protein metabolism and the metabolization of nutritional fats and the distribution of fat depots, is considered targeting a tentative starting up background for a gender concerned nutritional science.

Changes of Serum Adiponectin and Testosterone Concentrations Following Twelve Weeks Resistance Training in Obese Young Men

Background:

Circulating levels of adiponectin and testosterone decrease in obese men and this increases risks of cardiovascular disease and diabetes.

Objectives:

The purpose of this study was to survey changes of serum adiponectin and testosterone concentrations following twelve weeks resistance training in obese young men.

Patients and Methods:

In a semi-experimental study, twenty one obese young men were randomly placed in two groups: resistance training (26.5 ± 2.8 years) and control (27.4 ± 2.9 years). General characteristics of subjects and serum levels of adiponectin and testosterone were assessed before and after training. Resistance training protocol consisted of twelve weeks weight training (3 sessions per week, 10 exercises, 3 sets of 8 - 12 repetitions in each exercise, intensity 60% - 80% of one repetition maximum, rest between sets 1 minute and between exercises 2 minutes, duration of main training 20 - 40 minutes per each session).

Results:

Resistance training had no significant effect on body weight and body mass index (P > 0.05), whereas it decreased body fat percent (P = 0.017). Also, serum adiponectin (8.1 ± 1.8 vs. 10.5 ± 2.3 μg/mL) and testosterone concentrations (6.9 ± 2.4 vs. 8.2 ± 1.7 ng/mL) were increased after resistance training (P = 0.033, P = 0.018 respectively), while there were no significant changes in serum levels of these hormones in control group (P > 0.05).

Conclusions:

Twelve weeks of resistance training increased serum concentrations of adiponectin and testosterone in obese young men. With respect to inverse associations between changes of adiponectin and testosterone with BFP and insulin level variations after resistance training, it is recommended that obese young men do resistance training to benefit useful decreasing/preventive effects of this type of training against the risks of cardiovascular diseases and diabetes.

Current opinion on the role of testosterone in the development of prostate cancer: a dynamic model

BACKGROUND

Since the landmark study conducted by Huggins and Hodges in 1941, a failure to distinguish between the role of testosterone in prostate cancer development and progression has led to the prevailing opinion that high levels of testosterone increase the risk of prostate cancer. To date, this claim remains unproven.

PRESENTATION OF THE HYPOTHESIS

We present a novel dynamic mode of the relationship between testosterone and prostate cancer by hypothesizing that the magnitude of age-related declines in testosterone, rather than a static level of testosterone measured at a single point, may trigger and promote the development of prostate cancer.

TESTING THE HYPOTHESIS

Although not easily testable currently, prospective cohort studies with population-representative samples and repeated measurements of testosterone or retrospective cohorts with stored blood samples from different ages are warranted in future to test the hypothesis.

IMPLICATIONS OF THE HYPOTHESIS

Our dynamic model can satisfactorily explain the observed age patterns of prostate cancer incidence, the apparent conflicts in epidemiological findings on testosterone and risk of prostate cancer, racial disparities in prostate cancer incidence, risk factors associated with prostate cancer, and the role of testosterone in prostate cancer progression. Our dynamic model may also have implications for testosterone replacement therapy.

Endocrine causes of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the industrialized world. The prevalence of NAFLD is increasing, becoming a substantial public health burden. NAFLD includes a broad spectrum of disorders, from simple conditions such as steatosis to severe manifestations such as fibrosis and cirrhosis. The relationship of NAFLD with metabolic alterations such as type 2 diabetes is well described and related to insulin resistance, with NAFLD being recognized as the hepatic manifestation of metabolic syndrome. However, NAFLD may also coincide with endocrine diseases such as polycystic ovary syndrome, hypothyroidism, growth hormone deficiency or hypercortisolism. It is therefore essential to remember, when discovering altered liver enzymes or hepatic steatosis on radiological exams, that endocrine diseases can cause NAFLD. Indeed, the overall prognosis of NAFLD may be modified by treatment of the underlying endocrine pathology. In this review, we will discuss endocrine diseases that can cause NALFD. Underlying pathophysiological mechanisms will be presented and specific treatments will be reviewed.

Sex and sex steroids: impact on the kinetics of fatty acids underlying body shape

Adult humans have a remarkable sexual dimorphism in body shape. Men tend to store relatively more fat in the upper body whereas women store more fat in the lower body. We do not have a complete understanding of the mechanisms underlying these differences, but we know that people who preferentially store abdominal fat are at greater risk of metabolic disease. It is also known that the changes in sex steroid concentrations during puberty and again with advancing age are accompanied by changes in body fat distribution. The objective of this review is to describe what has been learned regarding the mechanisms underlying changes in regional body fat distribution that occur as a result of changes in sex hormones and to delineate effects of sex steroids in modulating body composition.

Body mass index is associated with physical performance in suburb-dwelling older chinese: a cross-sectional study

BACKGROUND

Physical performance is reported to have various beneficial effects on human health, especially in older individuals. Although such effects are associated with body mass index (BMI), the relationship between BMI and physical performance has not been clarified.

DESIGN

We conducted a cross-sectional study of 966 suburb-dwelling Tianjin individuals aged ≥ 60 years (average age 67.5±6.02, men 435, women 531). Mobility, balance, and muscle strength were assessed by walking speed, timed up-and-go test (TUGT), and grip strength, respectively. The subjects were categorized into three groups based on BMI (kg/m2) as follows: normal weight, 18.5 ≤ BMI ≤ 23.9; overweight, 24.0 ≤ BMI ≤ 27.9; and obese, BMI ≥ 28.0.

RESULT

After adjusting for all other variables, relative grip strength decreased when BMI increased in both men and women (P for trend <0.001 and <0.001, respectively). BMI may be negatively associated with TUGT performance in the women only. There was no apparent association between walking speed and BMI in either sex, but after adjusting for age, walking speed was faster when BMI increased in women (P for trend= 0.0162).

CONCLUSION

This study suggests that in older individuals, higher BMI is associated with poor muscle strength in both sexes.

Regulation of Estrogen Receptor α Expression in the Hypothalamus by Sex Steroids: Implication in the Regulation of Energy Homeostasis

Sex differences exist in the complex regulation of energy homeostasis that utilizes central and peripheral systems. It is widely accepted that sex steroids, especially estrogens, are important physiological and pathological components in this sex-specific regulation. Estrogens exert their biological functions via estrogen receptors (ERs). ERα, a classic nuclear receptor, contributes to metabolic regulation and sexual behavior more than other ER subtypes. Physiological and molecular studies have identified multiple ERα-rich nuclei in the hypothalamus of the central nervous system (CNS) as sites of actions that mediate effects of estrogens. Much of our understanding of ERα regulation has been obtained using transgenic models such as ERα global or nuclei-specific knockout mice. A fundamental question concerning how ERα is regulated in wild-type animals, including humans, in response to alterations in steroid hormone levels, due to experimental manipulation (i.e., castration and hormone replacement) or physiological stages (i.e., puberty, pregnancy, and menopause), lacks consistent answers. This review discusses how different sex hormones affect ERα expression in the hypothalamus. This information will contribute to the knowledge of estrogen action in the CNS, further our understanding of discrepancies in correlation of altered sex hormone levels with metabolic disturbances when comparing both sexes, and improve health issues in postmenopausal women.

Relationship between non-alcoholic fatty liver disease and benign prostatic hyperplasia/lower urinary tract symptoms: new insights from an Italian cross-sectional study

PURPOSE

To investigate the prevalence of non-alcoholic fatty liver disease (NAFLD) assessed by the fatty liver index (FLI), in lower urinary tract symptoms (LUTS) patients and to estimate its ability in predicting LUTS.

METHODS

We performed a cross-sectional analysis of 448 consecutive patients affected by LUTS. LUTS were evaluated using the IPSS questionnaire and metabolic syndrome (MetS) criteria (by International Diabetes Federation). FLI, prostate volume (PV), serum prostate-specific antigen, total testosterone (TT) and homeostasis model assessment (HOMA) index were evaluated. A value of FLI ≥40 was set to predict NAFLD. Patients were divided into Group A (FLI <40) and Group B (FLI ≥40). Odds ratios (OR) for having moderate-severe LUTS were calculated. Logistic regression model was fitted adjusting for confounding factors.

RESULTS

Group B showed higher prevalence of MetS, IR, moderate-severe LUTS and ED, higher IPSS, IPSS-storage, IPSS-voiding, total prostate volume, insulin, HOMA and lower TT and IIEF-5. Univariate logistic regression analysis demonstrated that continuous FLI (OR = 1.03, p < 0.05) and FLI ≥40 (OR = 2.41, p < 0.01) significantly increase the risk of moderate-severe LUTS. Continuous FLI (OR = 1.12, p < 0.01) and FLI ≥40 (OR = 5.39, p < 0.01) were independent predictors of moderate-severe LUTS at the multivariate logistic regression analysis, after adjusting for confounding factors. Subjects with MetS and FLI ≥40 had 2.0-fold the risk of moderate-severe LUTS (OR = 2.10, p < 0.01).

CONCLUSIONS

Non-alcoholic fatty liver disease (NAFLD) subjects have higher risk of LUTS. The presence of FLI ≥40 can be used to predict subjects at high risk of LUTS.

Exercise and dietary-mediated reductions in postprandial lipemia

Postprandial hyperlipemia produces long-term derangements in lipid/lipoprotein metabolism, vascular endothelial dysfunction, hypercoagulability, and sympathetic hyperactivity which are strongly linked to atherogenesis. The purpose of this review is to (1) provide a qualitative analysis of the available literature examining the dysregulation of postprandial lipid metabolism in the presence of obesity, (2) inspect the role of adiposity distribution and sex on postprandial lipid metabolism, and (3) examine the role of energy deficit (exercise- and/or energy restriction-mediated), isoenergetic low-carbohydrate diets, and omega-3 (n-3) fatty acid supplementation on postprandial lipid metabolism. We conclude from the literature that central adiposity primarily accounts for sex-related differences in postprandial lipemia and that aerobic exercise attenuates this response in obese or lean men and women to a similar extent through potentially unique mechanisms. In contrast, energy restriction produces only mild reductions in postprandial lipemia suggesting that exercise may be superior to energy restriction alone as a strategy for lowering postprandial lipemia. However, isoenergetic very low-carbohydrate diets and n-3 fatty acid supplementation reduce postprandial lipemia indicating that macronutrient manipulations reduce postprandial lipemia in the absence of energy restriction. Therefore, interactions between exercise/energy restriction and alterations in macronutrient content remain top priorities for the field to identify optimal behavioral treatments to reduce postprandial lipemia.

Testosterone and insulin resistance in the metabolic syndrome and T2DM in men

Obesity, type 2 diabetes mellitus and the metabolic syndrome are major risk factors for cardiovascular disease. Studies have demonstrated an association between low levels of testosterone and the above insulin-resistant states, with a prevalence of hypogonadism of up to 50% in men with type 2 diabetes mellitus. Low levels of testosterone are also associated with an increased risk of all-cause and cardiovascular mortality. Hypogonadism and obesity share a bidirectional relationship as a result of the complex interplay between adipocytokines, proinflammatory cytokines and hypothalamic hormones that control the pituitary-testicular axis. Interventional studies have shown beneficial effects of testosterone on components of the metabolic syndrome, type 2 diabetes mellitus and other cardiovascular risk factors, including insulin resistance and high levels of cholesterol. Biochemical evidence indicates that testosterone is involved in promoting glucose utilization by stimulating glucose uptake, glycolysis and mitochondrial oxidative phosphorylation. Testosterone is also involved in lipid homeostasis in major insulin-responsive target tissues, such as liver, adipose tissue and skeletal muscle.

Abdominal body composition measured by quantitative computed tomography and risk of non-spine fractures: the Osteoporotic Fractures in Men (MrOS) Study

The effect of abdominal adiposity and muscle on fracture is unclear in older men; therefore, we examined the association among 749 men aged 65+. Among various adipose tissues and muscle groups, lower psoas muscle volume and higher fatty infiltration of abdominal muscle contribute to higher fracture risk independent of BMD.

INTRODUCTION

The association of abdominal adiposity and muscle composition with incident fracture is unclear, especially in older men. Therefore, we examined the relationship of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), abdominal intermuscular adipose tissue (IMAT), and muscle volume with incident non-spine fractures among 749 men aged 65 and older.

METHODS

A case-cohort study design was used with a total of 252 fracture cases and 497 non-cases. We measured volumes (in centimeters) of adipose and muscle tissues obtained from quantitative computed tomography scan at the L4-5 intervertebral space. Three groups of muscle and IMAT were evaluated: total abdominal, psoas, and paraspinal. Cox proportional hazards regression with a robust variance estimator was used to estimate the hazard ratio (HR) of non-spine fractures per standard deviation (SD) increase in the abdominal body composition measures. The mean age among men in the random subcohort was 74.2 ± 6.1 years, and the average follow-up time was 5.2 ± 1.1 years.

RESULTS

After adjusting for age, race, clinic site, percent body fat, and femoral neck bone mineral density (BMD), no significant relationship was found between incident fractures and SAT or VAT. One SD increase in muscle volume at the psoas, but not paraspinal, was associated with 28 % lower fracture risk (95 % CI = 0.55-0.95). When IMAT models were further adjusted for corresponding muscle volumes, only abdominal IMAT was significantly associated with fracture risk (HR = 1.30 (95 % CI = 1.04-1.63)).

CONCLUSION

Our findings suggest that lower total psoas muscle volume and higher IMAT of the total abdominal muscle contribute to higher fracture risk in older men independent of BMD.

Sex steroid hormone levels and body composition in men

BACKGROUND

Previous studies indicate that testosterone (T) is positively correlated with lean mass and inversely correlated with fat mass in men; however, the directionality of these associations, as well as the association with other hormones including estradiol (E2) and SHBG, is unclear.

METHODS

We examined cross-sectional and longitudinal associations of E2, T, SHBG, and E2/T ratio with body composition among men ages 30 to 79 in the Boston Area Community Health/Bone Survey. Total, trunk, and appendicular lean and fat mass were measured by dual-energy x-ray absorptiometry at baseline, and weight and waist/hip circumference were measured at baseline and follow-up. Partial Pearson correlation coefficients were used to estimate the linear relationship between each body composition measure and log-transformed hormone variable.

RESULTS

In cross-sectional analyses of 821 men, T, calculated free T, and SHBG were inversely correlated with fat mass, weight, body mass index, waist/hip circumference, and waist-to-hip ratio, with multivariable-adjusted correlations ranging from -0.13 to -0.37. Calculated free E2 was positively correlated with percentage total (r = .13) and trunk (r = .15) fat mass, and E2/T was positively correlated with all measures examined (r = .13-.40). There were no significant multivariable-adjusted longitudinal associations between baseline hormone levels and change in weight, body mass index, waist/hip circumference, or waist-to-hip ratio after an average follow-up of 4.8 years.

CONCLUSIONS

We observed significant cross-sectional associations between hormone levels, including E2, T, and E2/T, and body composition measures in men. Longitudinal analyses showing no influence of baseline hormone levels on change in anthropometric measures imply that body composition affects hormone levels and not the reverse.

Androgen inhibits abdominal fat accumulation and negatively regulates the PCK1 gene in male chickens

Capons are male chickens whose testes have been surgically incised. Capons show a significant increase in fat accumulation compared to intact male chickens. However, while caponization leads to a significant reduction in androgen levels in roosters, little is known about the molecular mechanisms through which androgen status affects lipogenesis in avian species. Therefore, investigation of the influence of androgens on fat accumulation in the chicken will provide insights into this process. In this study, Affymetrix microarray technology was used to analyze the gene expression profiles of livers from capons and intact male chickens because the liver is the major site of lipogenesis in avian species. Through gene ontology, we found that genes involved in hepatic lipogenic biosynthesis were the most highly enriched. Interestingly, among the upregulated genes, the cytosolic form of the phosphoenolpyruvate carboxykinase (PCK1) gene showed the greatest fold change. Additionally, in conjunction with quantitative real-time PCR data, our results suggested that androgen status negatively regulated the PCK1 gene in male chickens.

A model for estimating body shape biological age based on clinical parameters associated with body composition

BACKGROUND

To date, no studies have attempted to estimate body shape biological age using clinical parameters associated with body composition for the purposes of examining a person's body shape based on their age.

OBJECTIVE

We examined the relations between clinical parameters associated with body composition and chronological age, and proposed a model for estimating the body shape biological age.

METHODS

The study was conducted in 243,778 subjects aged between 20 and 90 years who received a general medical checkup at health promotion centers at university and community hospitals in Korea from 2004 to 2011.

RESULTS

In men, the clinical parameters with the highest correlation to age included the waist- to-hip ratio (r = 0.786, P < 0.001), hip circumference (r = -0.448, P < 0.001), and height (r = -0.377, P < 0.001). In women, the clinical parameters with the highest correlation to age include the waist-to-hip ratio (r = 0.859, P < 0.001), waist circumference (r = 0.580, P < 0.001), and hip circumference (r = 0.520, P < 0.001). To estimate the optimal body shape biological age based on clinical parameters associated with body composition, we performed a multiple regression analysis. In a model estimating the body shape biological age, the coefficient of determination (R(2)) was 0.71 in men and 0.76 in women.

CONCLUSION

Our model for estimating body shape biological age might be a novel approach to variation in body shape that is due to aging. We assume that our estimation model would be used as an adjunctive measure in easily predicting differences in body shape with the use of clinical parameters that are commonly used to assess the status of obesity in a clinical setting.

Age trends in estradiol and estrone levels measured using liquid chromatography tandem mass spectrometry in community-dwelling men of the Framingham Heart Study

BACKGROUND

Age trends in estradiol and estrone levels in men and how lifestyle factors, comorbid conditions, testosterone, and sex hormone-binding globulin affect these age trends remain poorly understood, and were examined in men of the Framingham Heart Study.

METHODS

Estrone and estradiol concentrations were measured in morning fasting samples using liquid chromatography tandem mass spectrometry in men of Framingham Offspring Generation. Free estradiol was calculated using a law of mass action equation.

RESULTS

There were 1,461 eligible men (mean age [±SD] 61.1±9.5 years and body mass index [BMI] 28.8±4.5kg/m(2)). Total estradiol and estrone were positively associated with age, but free estradiol was negatively associated with age. Age-related increase in total estrone was greater than that in total estradiol. Estrone was positively associated with smoking, BMI, and testosterone, and total and free estradiol with diabetes, BMI, testosterone, and comorbid conditions; additionally, free estradiol was associated negatively with smoking. Collectively, age, BMI, testosterone, and other health and behavioral factors explained only 18% of variance in estradiol, and 9% of variance in estrone levels. Men in the highest quintile of estrone levels had significantly higher age and BMI, and a higher prevalence of smoking, diabetes, and cardiovascular disease than others, whereas those in the highest quintile of estradiol had higher BMI than others.

CONCLUSIONS

Total estrone and estradiol levels in men, measured using liquid chromatography tandem mass spectrometry, revealed significant age-related increases that were only partially accounted for by cross-sectional differences in BMI, diabetes status, and other comorbidities and health behaviors. Longitudinal studies are needed to confirm these findings.

Body fatness and sex steroid hormone concentrations in US men: results from NHANES III

OBJECTIVE

Obesity is associated with a variety of chronic diseases, including cancer, which may partly be explained by its influence on sex steroid hormone concentrations. Whether different measures of obesity, i.e., body mass index (BMI), waist circumference, and percent body fat were differentially associated with circulating levels of sex steroid hormones was examined in 1,265 men, aged 20-90+ years old, attending the morning examination session of the Third National Health and Nutrition Examination Survey (NHANES III).

MATERIALS AND METHODS

Serum hormones were measured by immunoassay. Weight, height, and waist circumference were measured by trained staff. Percent body fat was estimated from bioelectrical impedance. Multivariate linear regression was used to estimate associations between body fatness measures and hormone levels.

RESULTS

Total and free testosterone and sex hormone binding globulin concentrations decreased, whereas total and free estradiol increased with increasing BMI, waist circumference, and percent body fat (all p trend < 0.05). The magnitude of change in these hormones was similar for a one-quartile increase in each body fatness measure.

CONCLUSION

Measured BMI, waist circumference, and percent body fat led to similar inferences about their association with hormone levels in men.

Waist-to-height ratio as a predictor of serum testosterone in ageing men with symptoms of androgen deficiency

The decline in serum testosterone in ageing men may be mediated in part by obesity; however, it is uncertain which measure of adiposity is most closely associated with testosterone levels. We have examined the relationships of age, adiposity and testosterone levels in ageing men with symptoms consistent with hypoandrogenism but who were otherwise in good health. We conducted a cross-sectional study of non-smoking men aged ≥ 54 years recruited from the community and who were free of cancer or serious medical illness. Height (Ht), weight and waist circumference (WC) were measured, and body mass index (BMI) and waist-to-height (WHt) ratio were calculated. Two morning blood samples were collected for measurement of total testosterone (TT), sex hormone binding globulin (SHBG) and luteinizing hormone (LH). Free testosterone (cFT) was calculated. Multivariate linear regression analysis was performed to assess their relationship with measures of adiposity. Two hundred and seven men aged 54-86 years were studied. On univariate analysis WHt ratio was more strongly correlated with TT and cFT than either WC or BMI. Furthermore, in models of TT and cFT, the addition of Ht to WC resulted in an increase in the magnitude of the regression coefficients for both WC (inverse correlate) and Ht (positive correlate), with the contributions of both WC and Ht both being significant (P<0.05 for all). In conclusion, WHt ratio is the best anthropometric predictor of both TT and cFT in this group of healthy but symptomatic ageing men.

Significant associations of age, menopausal status and lifestyle factors with visceral adiposity in African-American and European-American women

BACKGROUND

Elevated visceral adiposity is strongly predictive of cardiometabolic disease, but, due to the high cost of biomedical imaging, assessment of factors contributing to normal variation in visceral (VAT) and subcutaneous (SAT) adipose tissue partitioning in large cohorts of healthy individuals are few, particularly in ethnic and racial minority populations.

OBJECTIVE

To describe age, menopausal status, smoking and physical activity differences in VAT and abdominal subcutaneous adipose tissue (ASAT) mass in African-American (AA) and European-American (EA) women.

METHODS

Magnetic resonance imaging measures of VAT and ASAT mass and VAT% (VAT/VAT+ASAT, %) were obtained from a cross-sectional sample of 617 EA and 111 AA non-diabetic women aged 18-80 years. Multivariate linear regression was used to test independent effects of the covariates.

RESULTS

VAT and VAT% were higher in EA than AA women (p < 0.01). Differences in VAT, ASAT and VAT% across age groups began in early adulthood in both ethnic groups, but the association of age with VAT% was stronger in EA women (p for interaction = 0.03). Current smokers had higher VAT and VAT% (p < 0.01) and lower TBF than non-smokers. Frequent participation in sports activities was associated with ∼30% lower VAT in older (>55 years) as well as younger ( < 40 years) women (p < 0.0001).

CONCLUSION

Greater allocation of abdominal adipose tissue into the visceral compartment occurs in EA than AA women and in older than younger women. Avoidance of cigarette smoking and frequent participation in sports activities may partially counteract this deleterious phenomenon of ageing.

Fatty acid metabolism in the elderly: effects of dehydroepiandrosterone and testosterone replacement in hormonally deficient men and women

CONTEXT

Aging, low dehydroepiandrosterone (DHEA), and testosterone are associated with increased adiposity and metabolic risk. Treatment with these hormones may improve these abnormalities.

OBJECTIVE

The objective of the study was to determine effects of aging, DHEA, or testosterone replacement on adiposity, meal fat partitioning, and postabsorptive lipolysis.

DESIGN

This was a cross-sectional, 2-yr, double-blind, randomized, placebo-controlled trial.

SETTING

The study was conducted in the general community.

PATIENTS

Elderly women and men (>or=60 yr) with low DHEA sulfate (women and men) and bioavailable testosterone (men) concentrations and young adults.

INTERVENTIONS

Thirty elderly women each received 50 mg DHEA or placebo daily for 2 yr. Thirty elderly men received 75 mg DHEA, 29 received 5 mg testosterone (patch), and 32 received placebo daily for 2 yr. Thirty young women and 32 young men served as controls.

MAIN OUTCOME MEASURES

In vivo measures of meal fat storage into sc fat, postabsorptive lipolysis, and regional adiposity at baseline and after treatment.

RESULTS

At baseline, the elderly had more body fat, greater systemic lipolysis (women, P = 0.0003; men, P < 0.0001) adjusted for resting energy expenditure, greater meal fat oxidation (women, P = 0.026; men, P = 0.0025), and less meal fat storage in sc fat (women, P = 0.0139; men, P= 0.0006). Although testosterone treatment increased meal fat storage into upper- vs. lower-body fat in elderly men, neither hormone affected regional adiposity, meal fat oxidation, or systemic lipolysis.

CONCLUSIONS

Aging, in the context of low DHEA sulfate (women and men) and bioavailable testosterone (men) concentrations, is associated with changes in meal fat partitioning and postabsorptive lipolysis that are not corrected by DHEA and only partly corrected by testosterone replacement.

The association of testosterone levels with overall sleep quality, sleep architecture, and sleep-disordered breathing

CONTEXT

Little is known about the association of low endogenous testosterone levels and abnormal sleep patterns in older men, although pharmacological doses of testosterone are associated with increased severity of sleep apnea and other sleep disturbances.

OBJECTIVE

The objective of the study was to examine the association between serum testosterone levels with objectively measured sleep characteristics.

DESIGN

This was a cohort study.

SETTING

Community-dwelling men aged 65 yr or older from six clinical centers in the United States participated in the study.

PARTICIPANTS AND MAIN OUTCOME MEASURES

A total of 1312 men had baseline total testosterone levels measured in 2000-2002, followed 3.4 yr later by 72-h (minimum) actigraphy and one-night in-home polysomnography to assess sleep duration, sleep fragmentation, and sleep apnea. Analyses were performed by quartile of total testosterone and categorically defined low vs. higher total testosterone (<250 ng/dl vs. > or =250 ng/dl). Lifestyle and body size were covariates.

RESULTS

Total testosterone levels were unrelated to age or duration of sleep. Men with lower testosterone levels had lower sleep efficiency, with increased nocturnal awakenings and less time in slow-wave sleep as well as a higher apnea-hypopnea index and more sleep time with O(2) saturation levels below 90%. Low testosterone levels were associated with overweight, and all significant associations were attenuated or absent after adjusting for body mass index or waist circumference. In a post hoc analysis in men with higher body mass index (>27 kg/m2), testosterone was significantly associated with more periods awake after sleep onset and lower sleep efficiency.

CONCLUSION

Low total testosterone levels are associated with less healthy sleep in older men. This association is largely explained by adiposity. Clinical trials are necessary to determine whether body weight acts directly or indirectly (via low testosterone) in the causal pathway for sleep-disordered breathing in older men.

Fat feeding potentiates the diabetogenic effect of dexamethasone in Wistar rats

Background

The role of cortisol and its increased action/availability is implicated in the pathogenesis of insulin resistance associated with obesity and metabolic syndrome but the mechanism of increased action/availability is not known. Availability of several other lipophilic hormones, drugs and pollutants are also reported to be increased in obesity. Increased lipids in the circulation are reported to alter the fluidity and permeability of membranes. Hyperlipidemia is also reported to alter the pharmacokinetics and pharmacodynamics of lipophilic molecules and also membrane fluidity and permeability. In this context we assumed that the hyperlipidemia associated with human obesity might play a role in the altered action/availability of cortisol and this in turn might have initiated the metabolic complications. To evaluate our assumption we have administered dexamethasone [low [50 μg/kg/day] or high [250 μg/kg/day] dose] to high-fat [coconut oil & vanaspati] fed rats and the results were compared with rats administered with either dexamethasone or high-fat.

Results and Discussion

Within two weeks, the rats co-administered with high-fat and dexamethasone developed severe hyperglycemia, hyperlipidemia and insulin resistance compared to rats treated either of them alone. High-fat fed rats treated with higher dose of dexamethasone were presented with severe hyperglycemia, insulin resistance and also severe glycosuria. The hyperlipidemia caused by high-fat feeding might have altered the transport and distribution of dexamethasone, probably by altering the physical state of membranes and transport proteins.

Conclusion

From the results obtained, it can be speculated that the altered lipid and cortisol metabolism could affect one another, forming a vicious cycle.

Effect of exercise on serum sex hormones in men: a 12-month randomized clinical trial

PURPOSE

The effect of exercise on androgens in middle-aged to older men is poorly understood, and it could have implications for several aspects of health. This analysis was conducted to examine the effects of long-term aerobic exercise on serum sex hormones in middle-aged to older men.

METHODS

One hundred two sedentary men, ages 40-75 yr, were randomly assigned to a 12-month exercise intervention or a control group (no change in activity). The combined facility- and home-based exercise program consisted of moderate/vigorous-intensity aerobic activity for 60 min.d(-1), 6 d.wk(-1). Serum concentrations of testosterone, free testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol glucuronide (3alpha-Diol-G), estradiol, free estradiol, and sex hormone-binding globulin (SHBG) were measured at baseline, 3, and 12 months.

RESULTS

Exercisers trained a mean of 370 min.wk(-1) (102% of goal), with only two dropouts. Cardiopulmonary fitness (.VO(2max)) increased 10.8% in exercisers and decreased by 1.8% in controls (P < 0.001). DHT increased 14.5% in exercisers versus 1.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.6% above baseline in exercisers versus a 3.1% decrease in controls (P = 0.03). SHBG increased 14.3% in exercisers versus 5.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.9% above baseline in exercisers versus 4.0% in controls (P = 0.13). There were significant trends toward increasing DHT and SHBG, with greater increases in .VO(2max) at 3 and 12 months in exercisers. No statistically significant differences were observed for testosterone, free testosterone, 3alpha-Diol-G, estradiol, or free estradiol in exercisers versus controls.

CONCLUSIONS

A year-long, moderate-intensity aerobic exercise program increased DHT and SHBG, but it had no effect on other androgens in middle-aged to older men.

Associations of androgens with physical activity and fitness in young black and white men: the CARDIA Male Hormone Study

OBJECTIVE

The association between physical activity or cardiovascular fitness and chronic disease risk in men might be mediated, in part, through androgens. Limited data exists on the potential associations of activity or fitness with serum hormones. We examined the associations of serum testosterone and sex hormone binding globulin (SHBG) concentrations with physical activity and cardiorespiratory fitness in black and white young men.

METHOD

Data were collected from 391 black and 604 white male participants of the Coronary Artery Risk Development in (Young) Adults (CARDIA) Male Hormone Study aged 24-32 in 1992-1993. Cross-sectional associations of serum total testosterone (TT), bioavailable testosterone (BT) and SHBG levels with self-reported total physical activity score, and in a subset of men (n=617) with cardiorespiratory fitness measured via duration on a treadmill test were assessed. Five-year longitudinal associations of change in hormones with changes in physical activity also were examined.

RESULTS

There were no cross-sectional or longitudinal associations of physical activity with SHBG, TT or BT in either black or white men. Fitness was positively associated with SHBG only in white men, but was not associated with TT or BT in either group.

CONCLUSION

Overall the results do not support an association of self-reported physical activity with androgens, whereas they do suggest that fitness might be associated with SHBG in white men.

Obesity and sex steroids during gonadotropin-releasing hormone agonist treatment for prostate cancer

PURPOSE

To evaluate effects of obesity on sex steroid levels during treatment with a gonadotropin-releasing hormone agonist in men with prostate cancer.

EXPERIMENTAL DESIGN

Forty-nine hormone-naïve men with recurrent or locally advanced prostate cancer were included in the analyses. All subjects were treated with leuprolide 3-month depot for 48 weeks. Serum levels of estradiol, sex hormone-binding globulin, total testosterone, and free testosterone were assessed at baseline, 24 weeks, and 48 weeks. Subjects were categorized by body mass index (BMI) and percent body fat.

RESULTS

Pretreatment serum sex hormone-binding globulin and total testosterone levels were significantly lower in overweight and obese men than in men with normal BMI. In the overall study population, mean serum testosterone concentrations decreased from 372 +/- 18 ng/dL at baseline to 13 +/- 1 ng/dL at week 48 (P < 0.001). Free testosterone decreased from 6.75 +/- 0.33 ng/dL at baseline to 0.21 +/- 0.02 ng/dL at week 48 (P < 0.001). During treatment with leuprolide, obese men had significantly higher total and free testosterone levels than men with normal BMI. Compared with normal men, total and free testosterone levels during treatment were 1.8-fold and 2.3-fold higher in obese men. Similar results were observed when subjects were categorized by body fat.

CONCLUSIONS

Despite lower pretreatment serum testosterone levels, obese men have higher total and free testosterone levels during leuprolide treatment than men with normal BMI. These differences may contribute to the association between obesity and increased prostate cancer mortality.

Double blind randomized placebo-controlled trial on the effects of testosterone supplementation in elderly men with moderate to low testosterone levels: design and baseline characteristics [ISRCTN23688581]

In ageing men testosterone levels decline, while cognitive function, muscle and bone mass, sexual hair growth, libido and sexual activity decline and the risk of cardiovascular diseases increase. We set up a double-blind, randomized placebo-controlled trial to investigate the effects of testosterone supplementation on functional mobility, quality of life, body composition, cognitive function, vascular function and risk factors, and bone mineral density in older hypogonadal men.

We recruited 237 men with serum testosterone levels below 13.7 nmol/L and ages 60–80 years. They were randomized to either four capsules of 40 mg testosterone undecanoate (TU) or placebo daily for 26 weeks. Primary endpoints are functional mobility and quality of life. Secondary endpoints are body composition, cognitive function, aortic stiffness and cardiovascular risk factors and bone mineral density. Effects on prostate, liver and hematological parameters will be studied with respect to safety.

Measure of effect will be the difference in change from baseline visit to final visit between TU and placebo. We will study whether the effect of TU differs across subgroups of baseline waist girth (< 100 cm vs. ≥ 100 cm; testosterone level (<12 versus ≥ 12 nmol/L), age (< median versus ≥ median), and level of outcome under study (< median versus ≥ median).

At baseline, mean age, BMI and testosterone levels were 67 years, 27 kg/m² and 10.72 nmol/L, respectively.

Waist circumference and testosterone levels in community dwelling men. The Tromsø study

To examine the relationship of total and free testosterone and sex hormone-binding globulin (SHBG) with central obesity in men, we studied 1548 men aged 25-84 years that took part in the 1994--1995 survey of the Tromsø study. Total testosterone and SHBG were measured by immuno-assay and the free testosterone fraction was calculated. These measurements were analyzed in relation to anthropometric data and lifestyle factors. The age-adjusted correlation between waist circumference (WC) and total testosterone was -0.34 (p < 0.001), between WC and free testosterone -0.09 (p < 0.001) and, between WC and SHBG -0.44 (p < 0.001). Adjusting for BMI and lifestyle factors weakened, but did not eliminate these associations. All hormone and SHBG associations were stronger for WC than for waist-hip ratio or BMI. In age- and BMI-adjusted analyses men with a WC > or = 102 cm had significantly lower levels of total testosterone and SHBG compared to men with an optimal WC, defined as < 94 cm (12.3 vs. 13.9 nmol/l; p < 0.01 and 48.5 vs. 55.1 nmol/l; p < 0.001, respectively). The lowest levels of total and free testosterone were observed in men with relatively high WC despite relatively low overall obesity (BMI), suggesting that WC should be the preferred anthropometric measurement in predicting endogenous testosterone levels.