Prevalence of Vertebral Fractures and Non-fracture Deformities in Healthy Adult Men: The Importance of Morphologic Criteria.

Vertebral fractures (VF) are common in older men but data on VF prevalence in young men is limited. The aim of this study was to describe the prevalence of VF and non-fracture vertebral deformities (VD) in healthy young to middle-aged men, and compare the characteristics of men with normal vertebrae, VF and VD. In this cross-sectional study, vertebral fracture assessment by dual-energy X-ray absorptiometry was performed in 650 men, aged 32 to 60 years (mean 46.2), from the population-based SIBLOS-SIBEX cohort. For VF and VD assessment, both the modified algorithm-based qualitative approach (morphologic criteria) to discriminate VF from VD and the semi-quantitative (morphometric) grading system of Genant (GSQ) were used. We found 48 (0.6%) fractured vertebrae, of which 15 were classified grade 1, 29 grade 2 and 4 grade 3 VF. There were 378 (4.7%) VD, of which 296 were scored grade 1, 82 grade 2 and none grade 3 VD. Twenty-six participants (4%) had VF, 15 had one and 11 had 2 or more VF. Two hundred and twenty-eight (35.1%) men had VD. Femoral neck, total hip and lumbar spine areal bone mineral density (aBMD) were lower in men with VF than in those with normal vertebrae or VD. Men with VD, in turn, had aBMD values similar to men with normal vertebrae. Our results suggest that -even in young healthy men-using the GSQ without taking qualitative aspects into account overestimates VF prevalence, confirming the importance of morphologic criteria to correctly diagnose and distinguish VF from VD.

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

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

[Depression and intermittent hypercortisolism: a difficult differential diagnostic process]. / Differentiaaldiagnose bij depressie en intermitterend hypercortisolisme.

Both Cushing’s and pseudo-Cushing’s syndrome involve a state of hypercortisolism. Cushing’s syndrome is a progressive multisystemic disease, caused by either the administration of corticosteroids, or the overproduction of cortisol by a tumoral process. In pseudo-Cushing’s syndrome the HPA-axis is hyperactive due to a pathophysiological process, most frequently caused by depression. The existence of a cyclic variant of Cushing’s syndrome, characterised by intermittent hypercortisolism, complicates the diagnosis in a patient with for example depression. In case of remaining intermittent hypercortisolism after remission of the depression, extreme hypercortisolism and (suspicion of) a tumor, we have to consider a cyclic Cushing syndrome. Also, in patients with treatment resistant depression or depression with atypical features combined with intermittent hypercortisolism psychiatrists have to consider a cyclic Cushing syndrome.

Primary sellar melanocytoma.

PURPOSE: We present an up-to-date review of all published cases of sellar melanocytoma, a benign melanocytic neoplasm arising from melanocytes present in the leptomeninges surrounding the pituitary. METHODS: Both the Medline and Embase databases were searched for case reports or case series of patients with a sellar mass consisting of melanocytes. RESULTS: All 14 identified patients developed symptoms due to compression of the surrounding structures. Symptoms included pituitary dysfunction and visual impairment. All patients received a transsphenoidal resection as first-line treatment. The diagnosis is made on pathological examination but deciding whether a sellar melanocytic tumor is best classified as a melanocytoma or a melanoma is not straightforward. DISCUSSION: Genetic analyses can help differentiate between central nervous system origin and metastasis of a cutaneous melanoma with the presence of a GNAQ and GNA11 mutations or a BRAF mutation, respectively. First choice treatment is complete resection, and in case of incomplete resection or recurrence additional radiotherapy is advised.

The Belgian Bone Club 2020 guidelines for the management of osteoporosis in postmenopausal women.

PURPOSE: To provide updated evidence-based guidelines for the management of osteoporosis in postmenopausal women in Belgium. METHODS: The Belgian Bone Club (BBC) gathered a guideline developer group. Nine "Population, Intervention, Comparator, Outcome" (PICO) questions covering screening, diagnosis, non-pharmacological and pharmacological treatments, and monitoring were formulated. A systematic search of MEDLINE, the Cochrane Database of Systematic Reviews, and Scopus was performed to find network meta-analyses, meta-analyses, systematic reviews, guidelines, and recommendations from scientific societies published in the last 10 years. Manual searches were also performed. Summaries of evidence were provided, and recommendations were further validated by the BBC board members and other national scientific societies' experts. RESULTS: Of the 3840 references in the search, 333 full texts were assessed for eligibility, and 129 met the inclusion criteria. Osteoporosis screening using clinical risk factors should be considered. Patients with a recent (<2 years) major osteoporotic fracture were considered at very high and imminent risk of future fracture. The combination of bone mineral density measured by dual-energy X-ray absorptiometry and 10-year fracture risk was used to categorize patients as low or high risk. Patient education, the combination of weight-bearing and resistance training, and optimal calcium intake and vitamin D status were recommended. Antiresorptive and anabolic osteoporosis treatment should be considered for patients at high and very high fracture risk, respectively. Follow-up should focus on compliance, and patient-tailored monitoring should be considered. CONCLUSION: BBC guidelines and 25 guideline recommendations bridge the gap between research and clinical practice for the screening, diagnosis, and management of osteoporosis.

How to manage osteoporosis before the age of 50.

This narrative review discusses several aspects of the management of osteoporosis in patients under 50 years of age. Peak bone mass is genetically determined but can also be affected by lifestyle factors. Puberty constitutes a vulnerable period. Idiopathic osteoporosis is a rare, heterogeneous condition in young adults due in part to decreased osteoblast function and deficient bone acquisition. There are no evidence-based treatment recommendations. Drugs use can be proposed to elderly patients at very high risk. Diagnosis and management of osteoporosis in the young can be challenging, in particular in the absence of a manifest secondary cause. Young adults with low bone mineral density (BMD) do not necessarily have osteoporosis and it is important to avoid unnecessary treatment. A determination of BMD is recommended for premenopausal women who have had a fragility fracture or who have secondary causes of osteoporosis: secondary causes of excessive bone loss need to be excluded and treatment should be targeted. Adequate calcium, vitamin D, and a healthy lifestyle should be recommended. In the absence of fractures, conservative management is generally sufficient, but in rare cases, such as chemotherapy-induced osteoporosis, antiresorptive medication can be used. Osteoporosis in young men is most often of secondary origin and hypogonadism is a major cause; testosterone replacement therapy will improve BMD in these patients. Diabetes is characterized by major alterations in bone quality, implying that medical therapy should be started sooner than for other causes of osteoporosis. Primary hyperparathyroidism, hyperthyroidism, Cushing's syndrome and growth hormone deficiency or excess affect cortical bone more often than trabecular bone.

A randomized trial on the effect of oral combined estradiol and drospirenone on glucose and insulin metabolism in healthy menopausal women with a normal oral glucose tolerance test.

BACKGROUND: Menopause is often associated with a central accumulation of body fat. This provokes insulin resistance. The resulting hyperinsulinemia may increase the risk of diabetes, cardiovascular disease and breast cancer. Long-term studies indicate that menopausal hormone therapy (MHT) reduces insulin resistance. To broaden knowledge of the mechanisms behind the influence of MHT on glucose homeostasis we focused on the direct short-term effects of MHT with oral combined estradiol and drospirenone on glucose and insulin metabolism in healthy postmenopausal women. METHODS: This randomized, placebo-controlled study recruited 80 healthy postmenopausal women. Women were randomized to treatment with estradiol 1 mg continuously combined with drospirenone 2 mg or placebo for 6-8 weeks. All participants underwent an oral glucose tolerance test (OGTT) before and after the treatment period. Glucose, insulin, fructosamine and C-peptide levels were measured in serum before and 30, 60, 90, 120 and 150 min after a 75-gram oral glucose challenge. RESULTS: After intervention, significantly higher glucose levels at 120 min (p < 0.024) and 150 min (p < 0.030) were observed in the MHT group compared with the placebo group. These glucose levels remained within the normal range. A significantly lower insulin peak serum level (p < 0.040) and a non-significantly smaller area under the curve (AUC) for insulin levels (p = 0.192) was observed in the MHT group at the end of the study period relative to baseline. No significant change in the insulin AUC in the placebo group was observed. There were no significant differences in fructosamine, HOMA-IR and C-peptide levels between the MHT group and the placebo group. CONCLUSION: This double-blind randomized study (EC/2008/694) indicates that treating healthy, postmenopausal women with 1 mg estradiol continuously combined with 2 mg drospirenone significantly decreases peak insulin levels and increases peak glucose levels during an OGTT compared to placebo. These glucose levels remained within the normal range.

Higher fracture prevalence and smaller bone size in patients with hEDS/HSD-a prospective cohort study.

Increased fracture risk in patients with Ehlers-Danlos syndromes has been reported, but the reasons for it are incompletely understood. We aimed to investigate possible determinants of this increased risk and found that hEDS/HSD patients present with a cortical bone size deficit compared with control subjects, possibly related to lower mechanical loading. INTRODUCTION: The Ehlers-Danlos syndromes (EDS) comprise a group of heritable connective tissue disorders caused by defects in the biosynthesis, secretion, and/or organization of fibrillar collagens which might impair bone strength. Our aim was to compare fracture prevalence, volumetric and areal bone mineral density (BMD), bone geometry, muscle size and the muscle-bone interaction, body composition and longitudinal changes therein between patients with hypermobile EDS (hEDS) or hypermobility spectrum disorder (HSD), and healthy control subjects. METHODS: Cross-sectional data comprised 39 female hEDS/HSD patients (age 41 ± 11 years) and 43 age-matched controls. After 8 years, 27 hEDS/HSD and 17 control subjects were re-evaluated. Tibial trabecular and cortical volumetric BMD, bone mineral content (BMC), cortical bone geometry, and lower leg muscle cross-sectional area (CSA) were measured using pQCT. Body composition, areal BMD, and BMC were determined by DXA. RESULTS: At baseline, patients with hEDS/HSD presented with a smaller cortical bone area, smaller cortical thickness and muscle CSA, and a higher fracture prevalence than control subjects (all p < 0.05). No differences in areal or volumetric BMD were found. Longitudinally, muscle CSA decreased in both groups and muscle density decreased in the hEDS/HSD group (p < 0.001) whereas all bone parameters remained unchanged. CONCLUSION: hEDS/HSD patients have a cortical bone size deficit compared with controls, possibly contributing to their increased fracture risk. They presented with decreased muscle CSA but normal bone/muscle area ratio, suggesting that this bone size deficit is likely secondary to decreased mechanical loading. Further, there were no arguments for accelerated bone loss in hEDS/HSD subjects.

Predicting mortality and incident immobility in older Belgian men by characteristics related to sarcopenia and frailty.

There is an increasing awareness of sarcopenia in older people. We applied machine learning principles to predict mortality and incident immobility in older Belgian men through sarcopenia and frailty characteristics. Mortality could be predicted with good accuracy. Serum 25-hydroxyvitamin D and bone mineral density scores were the most important predictors. INTRODUCTION: Machine learning principles were used to predict 5-year mortality and 3-year incident severe immobility in a population of older men by frailty and sarcopenia characteristics. METHODS: Using prospective data from 1997 on 264 older Belgian men (n = 152 predictors), 29 statistical models were developed and tuned on 75% of data points then validated on the remaining 25%. The model with the highest test area under the curve (AUC) was chosen as the best. From these, ranked predictor importance was extracted. RESULTS: Five-year mortality could be predicted with good accuracy (test AUC of .85 [.73; .97], sensitivity 78%, specificity 89% at a probability cut-off of 22.3%) using a Bayesian generalized linear model. Three-year incident severe immobility could be predicted with fair accuracy (test AUC .74 [.57; .91], sensitivity 67%, specificity 78% at a probability cut-off of 14.2%) using a multivariate adaptive regression splines model. Serum 25-hydroxyvitamin D levels and hip bone mineral density scores were the most important predictors of mortality, while biochemical androgen markers and Short-Form 36 Physical Domain questions were the most important predictors of immobility. Sarcopenia assessed by lean mass estimates was relevant to mortality prediction but not immobility prediction. CONCLUSIONS: Using advanced statistical models and a machine learning approach 5-year mortality can be predicted with good accuracy using a Bayesian generalized linear model and 3-year incident severe immobility with fair accuracy using a multivariate adaptive regression splines model.

Serum vascular cell adhesion molecule-1 predicts significant liver fibrosis in non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and is strongly associated with obesity, dyslipidemia and insulin resistance. NAFLD often presents as simple steatosis (NAFL) but can progress to non-alcoholic steatohepatitis (NASH) and fibrosis. Current non-invasive biomarkers are not tailored to identify significant (⩾F2) fibrosis, although recent guidelines recommend a stringent follow-up of this patient population. We and others have reported on the role of pathological angiogenesis in the pathogenesis of NAFLD, highlighting pro-angiogenic factors as potential diagnostic markers. OBJECTIVE: To investigate the applicability of angiogenic and endothelial dysfunction markers as non-invasive diagnostic tools for NASH or NASH-associated fibrosis in obese patients. METHODS: In a prospective cross-sectional study, male patients undergoing bariatric surgery (n=61) and control patients (n=35) were recruited. Serum protein levels and visceral adipose tissue gene expression of endothelial dysfunction and angiogenic markers were analyzed by multiplex bead-based assay and quantitative RT-PCR, respectively. For validation, we recruited a second cohort of patients undergoing bariatric surgery (n=40) and a cohort of NAFLD patients from our outpatient clinic (n=30). RESULTS: We identified serum vascular cell adhesion molecule-1 (VCAM-1) as an independent predictor for ⩾F2 fibrosis (median 14.0 vs 8.7 ng ml-1 in patients with and without significant fibrosis; P<0.0001) with an area under the receiver-operating characteristics (AUROC) curve of 0.80. The cutoff point of 13.2 ng ml-1 showed a sensitivity of 80% and specificity of 83%. In line with these results, VCAM-1 visceral adipose tissue gene expression was also elevated in patients with fibrosis (P=0.030). In the bariatric surgery and clinical validation cohorts, VCAM-1 displayed similar AUROCs of 0.89 and 0.85, respectively. CONCLUSIONS: VCAM-1 levels are able to accurately predict significant (⩾F2) fibrosis in NAFLD patients.

Sex steroids in relation to cardiac structure and function in men.

The prevalence of testosterone substitution as well as of androgen deprivation therapy in men is increasing. This review aims to summarise available knowledge of the effects of sex steroids on cardiac structure and function in men. MEDLINE was searched through PubMed. Original studies, systematic reviews and meta-analyses, and relevant citations were screened. A short-term hormonal intervention study in healthy young men with respect to echocardiographic parameters of structure and function was performed. Preclinical research provides sufficient evidence for the heart as a substrate for sex hormones. In animals, administration of oestradiol appears to have beneficial effects on cardiac structure and function, whereas administration of testosterone to noncastrated animals adversely affects cardiac function. However, the effects of sex steroids on cardiac function and structure appear more heterogeneous in human observational studies while comparative, prospective studies in humans are lacking. It is concluded that although effects of testosterone substitution as well as of androgen deprivation on cardiac structure and function can be expected based on pre-clinical research, there exists an important knowledge gap of the effects of hormonal intervention in men. As such, there is a need to address this question in future prospective intervention trials.

Lower insulin sensitivity is related to lower relative muscle cross-sectional area, lower muscle density and lower handgrip force in young and middle aged non-diabetic men.

OBJECTIVES: This study investigated whether an association between insulin resistance (IR) and muscle parameters is appreciable in young healthy men, independent of obesity. Furthermore, markers of muscle metabolism and hormones/possible determinants, were explored. METHODS: 358 healthy young men were divided into a less and more insulin sensitive (LIS [age=33.2±5.4, BMI=23.4±2.3] and MIS [age=35.5±5.3, BMI=28.1±3.7]) group based on upper and lower quartile of HOMA-IR. Muscle cross-sectional area (CSA), -density, handgrip force, serum testosterone, estradiol, SHBG, Vitamin 25(OH)D, creatinine, IGF-1, IGFBP-3 and leptin levels were compared between these groups, correcting for differences in age, physical activity and fat mass. Correlations between HOMA-IR and these parameters, and between muscle measures and biochemical parameters, were calculated. RESULTS: LIS is related to lower relative muscle CSA, muscle density, muscle/fat CSA ratio, relative handgrip force and level of physical activity. Furthermore, lower levels in SHBG, testosterone, Vitamin 25(OH)D and higher leptin, IGF-1 and IGFBP-3 levels were observed in LIS. Bio available T, FT, TE2, FE2, bioavailable E2, serum and urinary creatinine levels did not differ between groups. CONCLUSION: Differences in muscle performance are already present in healthy men with lower insulin sensitivity and could be possibly modifiable risk factors for the development of type 2 diabetes.

Association of recently described adipokines with liver histology in biopsy-proven non-alcoholic fatty liver disease: a systematic review.

The prevalence of non-alcoholic fatty liver disease (NAFLD) is rising, as is the prevalence of obesity and type 2 diabetes. It is increasingly recognized that an impaired pattern in adipokine secretion could play a pivotal role in the development of NAFLD. We performed a systematic review to evaluate the potential link between newly described adipokines and liver histology in biopsy-proven NAFLD patients. A computerized literature search was performed in PubMed, EMBASE and Web of Science electronic databases. Thirty-one cross-sectional studies were included, resulting in a total of seven different investigated adipokines. Studies included in this review mainly had a good methodological quality. Most adipokines were suggested to be involved in the inflammatory response that develops within the context of NAFLD, either at hepatic or systemic level, and/or hepatic insulin resistance. Based on literature, clinical studies suggest that chemerin, resistin and adipocyte-fatty-acid-binding protein potentially are involved in NAFLD pathogenesis and/or progression. However, major inconsistency still exists, and there is a high need for larger studies, together with the need of standardized assays to determine adipokine levels.

Body composition, bone turnover, and bone mass in trans men during testosterone treatment: 1-year follow-up data from a prospective case-controlled study (ENIGI).

PURPOSE: To assess the evolution of body composition and bone metabolism in trans men during the first year of cross-sex hormonal therapy. METHODS: In a prospective controlled study, we included 23 trans men (female-to-male trans persons) and 23 age-matched control women. In both groups, we examined grip strength (hand dynamometer), biochemical markers of bone turnover (C-terminal telopeptides of type 1 collagen (CTX) and procollagen 1 aminoterminal propeptide (P1NP)), total body fat and lean mass, and areal bone mineral density (aBMD) by dual-X-ray absorptiometry (DXA) and fat and muscle area at the forearm and calf, bone geometry, and volumetric bone mineral density (vBMD) by peripheral quantitative computed tomography (pQCT), before treatment and after 1 year of treatment with undecanoate (1000 mg i.m./12 weeks). RESULTS: Before hormonal treatment, trans men had similar bone and body composition compared with control women. Testosterone treatment induced in trans men a gain in muscle mass (+10.4%) and strength and loss of fat mass (-9.7%) (all P<0.001) and increased the levels of P1NP and CTX (both P<0.01). Areal and volumetric bone parameters remained largely unchanged apart from a small increase in trabecular vBMD at the distal radius and in BMD at the total hip in trans men (P=0.036 and P=0.001 respectively). None of these changes were observed in the control group. CONCLUSIONS: Short-term testosterone treatment in trans men increased muscle mass and bone turnover. The latter may rather reflect an anabolic effect of testosterone treatment rather than bone loss.

(Patho)physiology of cross-sex hormone administration to transsexual people: the potential impact of male-female genetic differences.

There is a limited body of knowledge of desired and undesired effects of cross-sex hormones in transsexual people. Little attention has been given to the fact that chromosomal configurations, 46,XY in male-to-female transsexuals subjects (MtoF) and 46,XX in female-to-male transsexual subjects (FtoM), obviously, remain unchanged. These differences in their genomes cause sex differences in the functions of cells. This study reviews sex differences in metabolism/cardiovascular pathology, immune mechanisms, bone (patho)physiology and brain functions and examines whether they are, maybe partially, determined by genetic mechanisms rather than by (cross-sex) hormones. There do not appear to be major genetic impacts on the changes in bone physiology. Also immune functions are rather unaffected and the evidence for an increase of autoimmune disease in MtoF is preliminary. Brain functions of transsexuals may have differed from controls before cross-sex hormones; they do undergo shifts upon cross-sex hormone treatment, but there is no evidence for changes in sex-specific brain disease. The prevalence of cardiovascular disease is higher in MtoF receiving oestrogens than in FtoM receiving androgens. While type of oestrogen and route of administration might be significant, it is reasonable to speculate that nonhormonal/genetic factors play a role.

Serum sclerostin levels in men with idiopathic osteoporosis.

OBJECTIVE: Sclerostin inhibits osteoblast differentiation and bone formation. If aberrant sclerostin action is involved in less efficient bone acquisition in men with idiopathic low bone mass, this might be reflected in higher serum sclerostin levels. METHODS: In 116 men with idiopathic osteoporosis (≤65 years old), 40 of their sons and healthy controls, areal bone parameters were measured using dual-energy X-ray absorptiometry, and volumetric and geometric bone parameters were measured using peripheral quantitative computed tomography. Serum analytes were measured using immunoassays and estradiol (E2) levels using liquid chromatography-tandem mass spectrometry. RESULTS: Men with idiopathic low bone mass had lower levels of sclerostin than the controls (0.54±0.17 vs 0.66±0.23 ng/ml; P<0.001). In both groups, sclerostin levels were strongly associated with age; when adjusting for age, no associations with anthropometrics were observed (P>0.14). In multivariate analyses, sclerostin levels displayed a positive association with whole-body bone mineral content (BMC) and areal BMD (aBMD), as well as with trabecular and cortical volumetric bone mineral density (vBMD) at the tibia in the probands. No clear associations were observed in the control group, neither were sclerostin levels associated with BMC at the radius or lumbar spine (all P>0.11). Testosterone, but not E2, was inversely related to sclerostin levels in the probands. No difference in sclerostin levels was found in their sons when compared with their controls. CONCLUSION: Lower rather than higher serum sclerostin levels in the probands with idiopathic low bone mass suggest that aberrant sclerostin secretion is not involved in the pathogenesis of low bone mass in these subjects.

Short-term aromatase inhibition: effects on glucose metabolism and serum leptin levels in young and elderly men.

OBJECTIVE: To assess and compare the effects of short-term aromatase inhibition on glucose metabolism, lipid profile, and adipocytokine levels in young and elderly men. DESIGN AND METHODS: Ten elderly and nine young healthy men were randomized to receive letrozole 2.5 mg daily or placebo for 28 days in a crossover design. RESULTS: Both in young and elderly men, active treatment significantly increased serum testosterone (+128 and +99%, respectively) and decreased estradiol levels (-41 and -62%, respectively). Fasting glucose and insulin levels decreased in young men after active intervention (-7 and -37%, respectively) compared with placebo. Leptin levels fell markedly in both age groups (-24 and -25%, respectively), while adiponectin levels were not affected by the intervention. Lipid profile was slightly impaired in both groups, with increasing low density lipoprotein-cholesterol levels (+14%) in the younger age group and 10% lower levels of APOA1 in the elderly. A decline in IGF1 levels (-15%) was observed in the younger age group. No changes in weight or body mass index were observed in either young or old men. CONCLUSIONS: Short-term aromatase inhibition appears to affect glucose metabolism in young men, and lipid metabolism, including leptin secretion, in young and elderly men. Furthermore, the short period of exposure suggests that these changes might be mediated by direct effects of sex steroids rather than by changes in body composition.

The decline of serum testosterone levels in community-dwelling men over 70 years of age: descriptive data and predictors of longitudinal changes.

OBJECTIVE: This study was designed to assess longitudinal changes in serum testosterone levels, explore relationships with aging, genetic-, health-, and lifestyle-related factors, and investigate predictors of changes in healthy elderly men. DESIGN: Population-based, longitudinal, 4-year observational study in 221 community-dwelling men aged 71-86 years at baseline. METHODS: Hormone levels assessed by immunoassay, anthropometry, questionnaires on general health, and genetic polymorphisms. Predictors of changes in testosterone levels explored using linear mixed-effects modeling for longitudinal analyses. RESULTS: Total testosterone (TT), free testosterone, and bioavailable testosterone (BioT) levels decreased with aging, decreases in BioT being most marked. No changes in sex hormone-binding globulin (SHBG) or estradiol (E(2)), while LH and FSH levels increased during follow-up. Subjects who gained weight displayed a greater decline in TT levels, mainly due to decreasing SHBG levels. However, baseline body composition was not predictive of subsequent changes in testosterone levels. Baseline E(2) (P=0.023 to 0.004), LH (P=0.046 to 0.005), and FSH (P<0.002) levels were independently positively associated with a faster decline in testosterone fractions, although only FSH remained significant when adjusting for baseline testosterone (P=0.041-0.035). Carriers of a 'TA' haplotype of the estrogen receptor alpha gene (ER alpha) PvuII and XbaI polymorphisms displayed a slower decline of TT and BioT (P=0.041-0.007). CONCLUSIONS: In elderly men with already low serum testosterone levels, a further decline was observed, independent of baseline age. The identification of FSH levels as a predictor of this decline appears to reflect the testicular mechanisms of aging-related changes in testosterone production, whereas associations with E(2) and ER alpha polymorphisms are suggestive of estrogen-related processes, possibly related to changes in the neuroendocrine regulation of testosterone production.

Is the effect of testosterone on body composition modulated by the androgen receptor gene CAG repeat polymorphism in elderly men?

OBJECTIVE: The androgen receptor (AR) gene contains a CAG repeat polymorphism coding for a polyglutamine chain, the length of which is inversely correlated with AR transcriptional activity. We explored whether this polymorphism modulates the activities of testosterone (T) related to body composition in elderly men. DESIGN: We performed cross-sectional analyses using data from a 4-year follow-up study in community-dwelling men aged 75-89 years (n=159). METHODS: Body composition was assessed by dual-energy X-ray absorptiometry and its relation with T and the AR gene CAG repeat length was assessed by multiple linear regression analyses, adjusting for confounding and exploring effect modification. RESULTS: AR gene CAG repeat length was not directly related to body composition, either with or without adjustment for confounding variables like age, weight, total T or sex hormone binding globulin (SHBG) levels. However, exploration of effect modification showed that CAG repeat length modulated the relation between T and body composition (standardized regression coefficients of interaction term: beta=0.12, P<0.01 and beta=-0.09, P<0.05 for fat-free mass and fat mass respectively). These results were confirmed using similar models and data of mean T, SHBG and weight of the 2 years' preceding body composition assessment instead of data of the same year (beta=0.09, P<0.05 and beta=-0.09, P<0.05 respectively). CONCLUSION: These findings suggest that the AR gene CAG polymorphism contributes, albeit modestly, to the between-subject variation of T action on body composition in community-dwelling elderly men.