Effect of testosterone treatment on bone remodelling markers and mineral density in obese dieting men in a randomized clinical trial

Testosterone replacement in men with sexual dysfunction

BACKGROUND

Clinical practice guidelines recommend testosterone replacement therapy (TRT) for men with sexual dysfunction and testosterone deficiency. However, TRT is commonly promoted in men without testosterone deficiency and existing trials often do not clearly report participants' testosterone levels or testosterone-related symptoms. This review assesses the potential benefits and harms of TRT in men presenting with complaints of sexual dysfunction.

OBJECTIVES

To assess the effects of testosterone replacement therapy compared to placebo or other medical treatments in men with sexual dysfunction.

SEARCH METHODS

We performed a comprehensive search of CENTRAL (the Cochrane Library), MEDLINE, EMBASE, and the trials registries ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform, with no restrictions on language of publication or publication status, up to 29 August 2023.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in men (40 years or over) with sexual dysfunction. We excluded men with primary or secondary hypogonadism. We compared testosterone or testosterone with phosphodiesterase-5 inhibitors (PDEI5I) to placebo or PDE5I alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the literature, assessed the risk of bias, extracted data, and rated the certainty of evidence (CoE) according to GRADE using a minimally contextualized approach. We performed statistical analyses using a random-effects model and interpreted them according to standard Cochrane methodology. Predefined primary outcomes were self-reported erectile dysfunction assessed by a validated instrument, sexual quality of life assessed by a validated instrument, and cardiovascular mortality. Secondary outcomes were treatment withdrawal due to adverse events, prostate-related events, and lower urinary tract symptoms (LUTS). We distinguished between short-term (up to 12 months) and long-term (> 12 months) outcomes.

MAIN RESULTS

We identified 43 studies with 11,419 randomized participants across three comparisons: testosterone versus placebo, testosterone versus PDE5I, and testosterone with PDE5I versus PDE5I alone. This abstract focuses on the most relevant comparison of testosterone versus placebo. Testosterone versus placebo (up to 12 months) Based on a predefined sensitivity analysis of studies at low risk of bias, and an analysis combing data from the similar International Index of Erectile Function (IIEF-EF) and IIEF-5 instruments, TRT likely results in little to no difference in erectile function assessed with the IIEF-EF (mean difference (MD) 2.37, 95% confidence interval (CI) 1.67 to 3.08; I² = 0%; 6 RCTs, 2016 participants; moderate CoE) on a scale from 6 to 30 with larger values reflecting better erectile function. We assumed a minimal clinically important difference (MCID) of greater than or equal to 4. TRT likely results in little to no change in sexual quality of life assessed with the Aging Males' Symptoms scale (MD -2.31, 95% CI -3.63 to -1.00; I² = 0%; 5 RCTs, 1030 participants; moderate CoE) on a scale from 17 to 85 with larger values reflecting worse sexual quality of life. We assumed a MCID of greater than or equal to 10. TRT also likely results in little to no difference in cardiovascular mortality (risk ratio (RR) 0.83, 95% CI 0.21 to 3.26; I² = 0%; 10 RCTs, 3525 participants; moderate CoE). Based on two cardiovascular deaths in the placebo group and an assumed MCID of 3%, this would correspond to no additional deaths per 1000 men (95% CI 1 fewer to 4 more). TRT also likely results in little to no difference in treatment withdrawal due to adverse events, prostate-related events, or LUTS. Testosterone versus placebo (later than 12 months) We are very uncertain about the longer-term effects of TRT on erectile dysfunction assessed with the IIEF-EF (MD 4.20, 95% CI -2.03 to 10.43; 1 study, 42 participants; very low CoE). We did not find studies reporting on sexual quality of life or cardiovascular mortality. We are very uncertain about the effect of testosterone on treatment withdrawal due to adverse events. We found no studies reporting on prostate-related events or LUTS.

AUTHORS' CONCLUSIONS

In the short term, TRT probably has little to no effect on erectile function, sexual quality of life, or cardiovascular mortality compared to a placebo. It likely results in little to no difference in treatment withdrawals due to adverse events, prostate-related events, or LUTS. In the long term, we are very uncertain about the effects of TRT on erectile function when compared to placebo; we did not find data on its effects on sexual quality of life or cardiovascular mortality. The certainty of evidence ranged from moderate (signaling that we are confident that the reported effect size is likely to be close to the true effect) to very low (indicating that the true effect is likely to be substantially different). The findings of this review should help to inform future guidelines and clinical decision-making at the point of care.

Safety and Efficacy of Testosterone Therapy on Musculoskeletal Health and Clinical Outcomes in Men: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

OBJECTIVE

Age-related declines in muscle and bone, alongside a shift toward greater adiposity, contribute to falls and fracture risk. Testosterone is osteogenic, myogenic, and catabolic to fat. As such, we examined the effects of testosterone therapy on musculoskeletal health and clinical outcomes in men.

METHODS

Electronic databases (Medline, Embase, Web of Science, Central) were systematically searched for randomized controlled trials (RCTs) reporting on the effects of testosterone therapy versus placebo on any primary outcome (bone density, muscle mass, fat mass, muscle strength/physical performance) or secondary outcome (falls, fractures, disability, adverse events) in men (≥18 years). A random effects meta-regression examined the effects of testosterone on prespecified outcomes.

RESULTS

One thousand seven hundred twenty-eight men across 16 RCTs were included (mean age: 77.1 ± 7.6 years). Baseline mean serum testosterone ranged from 7.5 ± 0.3 to 18.9 ± 1.2 nmol/L. Compared to placebo, 6 months of testosterone therapy increased hip bone density and total lean mass, but effects for handgrip and total fat mass did not reach statistical significance. No significant effects of testosterone therapy on musculoskeletal outcomes were evident at 12 months. The limited number of RCTs reporting on adverse events/clinical outcomes, and the low incidence of these events across RCTs, prohibited statistical comparisons.

CONCLUSION

After 6 months, testosterone effectively increases hip bone density and total lean mass in men, but its effects are unclear for lumbar spine bone density and handgrip strength. Further, RCTs are needed to clarify the safety and efficacy of testosterone on musculoskeletal health and clinical outcomes.

The complex pathophysiology of bone fragility in obesity and type 2 diabetes mellitus: therapeutic targets to promote osteogenesis

Fractures associated with Type2 diabetes (T2DM) are major public health concerns in an increasingly obese and aging population. Patients with obesity or T2DM have normal or better than normal bone mineral density but at an increased risk for fractures. Hence it is crucial to understand the pathophysiology and mechanism of how T2DM and obesity result in altered bone physiology leading to increased fracture risk. Although enhanced osteoclast mediated bone resorption has been reported for these patients, the most notable observation among patients with T2DM is the reduction in bone formation from mostly dysfunction in osteoblast differentiation and survival. Studies have shown that obesity and T2DM are associated with increased adipogenesis which is most likely at the expense of reduced osteogenesis and myogenesis considering that adipocytes, osteoblasts, and myoblasts originate from the same progenitor cells. Furthermore, emerging data point to an inter-relationship between bone and metabolic homeostasis suggesting that these physiologic processes could be under the control of common regulatory pathways. Thus, this review aims to explore the complex mechanisms involved in lineage differentiation and their effect on bone pathophysiology in patients with obesity and T2DM along with an examination of potential novel pharmacological targets or a re-evaluation of existing drugs to improve bone homeostasis.

Changes in Health-related Parameters Associated with Sports Performance Enhancement Drugs

The purpose of this study was to evaluate changes in health-related parameters caused by the administration of anabolic-androgenic steroids and "fat-burning drugs" during a 6-month competition preparation period. The physiological, biochemical, and anthropometric parameters studied included serum cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, aspartate aminotransferase, alanine transaminase, bilirubin, body mass, and percentage of total body fat. Changes in the parameters studied were analyzed at monthly intervals during six months of preparation for competition. The study revealed a continuous increase in body mass, accompanied by a decrease in body fat percentage to the physiologically essential level. Total cholesterol levels remined in the desirable concentration range. The mean levels of triglycerides fluctuated between borderline high and high. Mean high-density lipoprotein cholesterol levels remained within the low range, while low-density lipoprotein cholesterol fluctuated between near-optimal / above-optimal, borderline high, and high levels. Serum levels of aspartate aminotransferase and alanine transaminase remained within the high concentration. The bilirubin concentration remained in the desirable range. The blood nitrogen urea concentration fluctuated between normal and elevated levels. Sports-enhancing drugs analyzed in this study do not have an immediate detrimental impact on the selected biochemical, physiological, and anthropometric parameters that define health.

Role of hormones in bone remodeling in the craniofacial complex: A review

Background

Diseases such as periodontitis and osteoporosis are expected to rise tremendously by 2050. Bone formation and remodeling are complex processes that are disturbed in a variety of diseases influenced by various hormones.

Objective

This study aimed to review and present the roles of various hormones that regulate bone remodeling of the craniofacial complex.

Methods

A literature search was conducted on PubMed and Google Scholar for studies related to hormones and jawbone. Search strategies included the combinations ("name of hormone" + "dental term") of the following terms: "hormones", "oxytocin", "estrogen", "adiponectin", "parathyroid hormone", "testosterone", "insulin", "angiotensin", "cortisol", and "erythropoietin", combined with a dental term "jaw bone", "alveolar bone", "dental implant", "jaw + bone regeneration, healing or repair", "dentistry", "periodontitis", "dry socket", "osteoporosis" or "alveolitis". The papers were screened according to the inclusion criteria from January 1, 2000 to March 31, 2021 in English. Publications included reviews, book chapters, and original research papers; in vitro studies, in vivo animal, or human studies, including clinical studies, and meta-analyses.

Results

Bone formation and remodeling is a complex continuous process involving many hormones. Bone volume reduction following tooth extractions and bone diseases, such as periodontitis and osteoporosis, cause serious problems and require a great understanding of the process.

Conclusion

Hormones are with us all the time, shape our development and regulate homeostasis. Newly discovered effects of hormones influencing bone healing open the possibilities of using hormones as therapeutics to combat bone-related diseases.

Impact of testosterone therapy on bone turnover markers in obese males with type 2 diabetes and functional hypogonadism

METHODS

Fifty-five obese males with type 2 diabetes mellitus and functional hypogonadism participated in a 2-year, double-blind, placebo-controlled study of testosterone undecanoate (TU). Bone turnover markers C-telopeptide of type I collagen (CTX) and procollagen I N-terminal propeptide (PINP) were assessed at baseline, 12 and 24 months. Bone mineral density (BMD) changes were evaluated after 24 months using dual-energy X-ray absorptiometry. Group T (n = 28) received TU both years. Group P (n = 27) received placebo first year and TU second year.

RESULTS

CTX decreased in group P from 1055 (676-1344) to 453 (365-665) pmol/L (p < 0.001) and from 897 (679-1506) to 523 (364-835) pmol/L (p < 0.001) in T. PINP decreased by 4.30 ± 8.05 μg/L in group P (p = 0.030) and 4.64 ± 8.86 μg/L in T (p < 0.023) after first year of therapy. No femoral neck BMD changes were observed in 32 patients from both groups (n = 16 per group). Lumbar spine BMD increased (by 0.075 ± 0.114 g/cm²; p = 0.019) in group T following two years of treatment.

CONCLUSIONS

We observed decreased CTX, decreased PINP and increased lumbar spine BMD after two years of testosterone treatment.

CLINICAL TRIALS

NCT03792321; retrospectively registered trial on 4 January 2019.

Bone health in ageing men

Osteoporosis does not only affect postmenopausal women, but also ageing men. The burden of disease is projected to increase with higher life expectancy both in females and males. Importantly, osteoporotic men remain more often undiagnosed and untreated compared to women. Sex steroid deficiency is associated with bone loss and increased fracture risk, and circulating sex steroid levels have been shown to be associated both with bone mineral density and fracture risk in elderly men. However, in contrast to postmenopausal osteoporosis, the contribution of relatively small decrease of circulating sex steroid concentrations in the ageing male to the development of osteoporosis and related fractures, is probably only minor. In this review we provide several clinical and preclinical arguments in favor of a 'bone threshold' for occurrence of hypogonadal osteoporosis, corresponding to a grade of sex steroid deficiency that in general will not occur in many elderly men. Testosterone replacement therapy has been shown to increase bone mineral density in men, however data in osteoporotic ageing males are scarce, and evidence on fracture risk reduction is lacking. We conclude that testosterone replacement therapy should not be used as a sole bone-specific treatment in osteoporotic elderly men.

Testosterone supplementation and bone parameters: a systematic review and meta-analysis study

BACKGROUND

The role of testosterone (T) replacement therapy (TRT) in subjects with late onset hypogonadism is still the object of an intense debate.

METHODS

All observational studies and placebo-controlled or -uncontrolled randomized trials (RCTs) comparing the effect of TRT on different bone parameters were considered.

RESULTS

Out of 349 articles, 36 were considered, including 3103 individuals with a mean trial duration of 66.6 weeks. TRT improves areal bone mineral density (aBMD) at the spine and femoral neck levels in observational studies, whereas placebo-controlled RTCs showed a positive effect of TRT only at lumber spine and when trials included only hypogonadal patients at baseline (total testosterone < 12 nM). The effects on aBMD were more evident in subjects with lower T levels at baseline and increased as a function of trial duration and a higher prevalence of diabetic subjects. Either T or estradiol increase at endpoint contributed to aBMD improvement. TRT was associated with a significant reduction of bone resorption markers in observational but not in controlled studies.

CONCLUSION

TRT is able to inhibit bone resorption and increase bone mass, particularly at the lumbar spine level and when the duration is long enough to allow the anabolic effect of T and estrogens on bone metabolism to take place.

Baseline Testosterone Predicts Body Composition and Metabolic Response to Testosterone Therapy

CONTEXT

Male hypogonadism adversely affects body composition, bone mineral density (BMD), and metabolic health. A previous report showed that pre-treatment testosterone (T) levels of <200 ng/dl is associated with greater improvement in spine BMD with T therapy. However, to date, there is no study that investigates whether baseline T levels also influence body composition and metabolic response to T therapy.

OBJECTIVE

The aim of this study is to determine if there are differences in the changes in body composition, metabolic profile, and bone turnover markers, in addition to BMD, in response to T therapy in men with a baseline T level of <264 ng/dl compared to those with levels ≥264 ng/dl.

METHODS

This is a secondary analysis of a single-arm, open-label clinical trial (NCT01378299) on pharmacogenetics of response to T therapy conducted between 2011 and 2016 involving 105 men (40-74 years old), with average morning T < 300 ng/dl, given intramuscular T cypionate 200 mg every 2 weeks for 18 months. Subjects were divided into those with baseline T levels of <264 ng/dl (N = 43) and those with ≥264 ng/dl (N = 57). T and estradiol (E2) were measured by liquid chromatography/mass spectrometry; serum bone turnover markers (C-telopeptide [CTX], osteocalcin, and sclerostin), adiponectin, and leptin were measured by enzyme-linked immunosorbent assay; glycated hemoglobin (HbA1c) was measured by high-performance liquid chromatography; and areal BMD and body composition was measured by dual-energy x-ray absorptiometry (DXA).

RESULTS

Men with T < 264 ng/dl showed greater increases in total fat-free mass (FFM) at 18 months compared to those with T ≥ 264 ng/dl (4.2 ± 4.1 vs. 2.7 ± 3.8%; p = 0.047) and unadjusted appendicular FFM at 6 and 18 months (8.7 ± 11.5 vs. 4.4 ± 4.3%, 7.3 ± 11.6 vs. 2.4 ± 6.8%; p = 0.033 and p = 0.043, respectively). Men with T ≥ 264 ng/dl showed significant decreases in HbA1c at 12 months (-3.1 ± 9.2 vs. 3.2 ± 13.9%; p = 0.005), fasting glucose at 18 months (-4.2 ± 31.9 vs. 13.0 ± 57.3%; p = 0.040), LDL at 6 months (-6.4 ± 27.5 vs. 12.8 ± 44.1%; p = 0.034), and leptin at 18 months (-40.2 ± 35.1 vs. -27.6 ± 31.0%; p = 0.034) compared to those with T < 264 ng/dl. No significant differences in BMD and bone turnover markers were observed.

CONCLUSION

T therapy results in improvement in body composition irrespective of baseline T levels but T < 264 ng/dl is associated with greater improvement in FFM, whereas a T level of ≥264 ng/dl favors improvement in metabolic profile.

Dysregulation of the Hypothalamic-Pituitary-Testicular Axis due to Energy Deficit

CONTEXT

Although gonadal axis dysregulation from energy deficit is well recognized in women, the effects of energy deficit on the male gonadal axis have received much less attention.

EVIDENCE ACQUISITION

To identify relevant articles, we conducted PubMed searches from inception to May 2021.

EVIDENCE SYNTHESIS

Case series and mechanistic studies demonstrate that energy deficit (both acutely over days or chronically over months) either from inadequate energy intake and/or excessive energy expenditure can lower serum testosterone concentration as a result of hypothalamic-pituitary-testicular (HPT) axis dysregulation in men. The extent to which this has clinical consequences that can be disentangled from the effects of nutritional insufficiency, concomitant endocrine dysregulation (eg, adrenal and thyroid axis), and coexisting comorbidities (eg, depression and substance abuse) is uncertain. HPT axis dysfunction is primarily the result of loss of GnRH pulsatility resulting from a failure of leptin to induce kisspeptin signaling. The roles of neuroendocrine consequences of depression, hypothalamic-pituitary-adrenal axis activation, proinflammatory cytokines, Ghrelin, and genetic susceptibility remain unclear. In contrast to hypogonadism from organic pathology of the HPT axis, energy deficit-associated HPT dysregulation is functional, and generally reversible by restoring energy balance.

CONCLUSIONS

The clinical management of such men should aim to restore adequate nutrition and achieve and maintain a healthy body weight. Psychosocial comorbidities must be identified and addressed. There is no evidence that testosterone treatment is beneficial. Many knowledge gaps regarding epidemiology, pathophysiology, and treatment remain and we highlight several areas that require future research.

Testosterone and Bone Health in Men: A Narrative Review

Bone fracture due to osteoporosis is an important issue in decreasing the quality of life for elderly men in the current aging society. Thus, osteoporosis and bone fracture prevention is a clinical concern for many clinicians. Moreover, testosterone has an important role in maintaining bone mineral density (BMD) among men. Some testosterone molecular mechanisms on bone metabolism have been currently established by many experimental data. Concurrent with a decrease in testosterone with age, various clinical symptoms and signs associated with testosterone decline, including decreased BMD, are known to occur in elderly men. However, the relationship between testosterone levels and osteoporosis development has been conflicting in human epidemiological studies. Thus, testosterone replacement therapy (TRT) is a useful tool for managing clinical symptoms caused by hypogonadism. Many recent studies support the benefit of TRT on BMD, especially in hypogonadal men with osteopenia and osteoporosis, although a few studies failed to demonstrate its effects. However, no evidence supporting the hypothesis that TRT can prevent the incidence of bone fracture exists. Currently, TRT should be considered as one of the treatment options to improve hypogonadal symptoms and BMD simultaneously in symptomatic hypogonadal men with osteopenia.

Mechanisms underlying the metabolic actions of testosterone in humans: A narrative review

The role of testosterone in improving sexual symptoms in men with hypogonadism is well known. However, recent studies indicate that testosterone plays an important role in several metabolic functions in males. Multiple PubMed searches were conducted with the use of the terms testosterone, insulin sensitivity, obesity, type 2 diabetes, anaemia, bone density, osteoporosis, fat mass, lean mass and body composition. This narrative review is focused on detailing the mechanisms that underlie the metabolic aspects of testosterone therapy in humans. Testosterone enhances insulin sensitivity in obese men with hypogonadism by decreasing fat mass, increasing lean mass, decreasing free fatty acids and suppressing inflammation. At a cellular level, testosterone increases the expression of insulin receptor β subunit, insulin receptor substrate-1, protein kinase B and glucose transporter type 4 in adipose tissue and adenosine 5'-monophosphate-activated protein kinase expression and activity in skeletal muscle. Observational studies show that long-term therapy with testosterone prevents progression from prediabetes to diabetes and improves HbA1c. Testosterone increases skeletal muscle satellite cell activator, fibroblast growth factor-2 and decreases expression of the muscle growth suppressors, myostatin and myogenic regulatory factor 4. Testosterone increases haematocrit by suppressing hepcidin and increasing expression of ferroportin along with that of transferrin receptor and plasma transferrin concentrations. Testosterone also increases serum osteocalcin concentrations, which may account for its anabolic actions on bone. In conclusion, testosterone exerts a series of potent metabolic effects, which include insulin sensitization, maintenance and growth of the skeletal muscle, suppression of adipose tissue growth and maintenance of erythropoiesis and haematocrit.

Follicle-stimulating hormone and estradiol are associated with bone mineral density and risk of fractures in men with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with a higher fracture risk. Sex hormones are important for maintaining skeletal health. It is not clear which sex hormone(s) contribute(s) to bone mineral density (BMD) and fracture risk in males with T2DM. This study investigated the relationships of these parameters in males with T2DM.

METHODS

This study involved 482 men with T2DM. BMDs at the lumbar spine (L2-4), femoral neck (FN), and total hip (TH) were measured by dual-energy X-ray absorptiometry (DXA). The 10-year probability of fractures was assessed using the modified Fracture Risk Algorithm (FRAX) tool. Serum levels of sex hormones were measured.

RESULTS

Follicle-stimulating hormone (FSH) and estradiol (E2) were associated with BMDs at L2-4 (FSH, β = -.162, P < .05; E2, β = .176, P < .001), and E2 was associated with BMD at FN (β = .137, P < .05) and TH (β = .140, P < .05). FSH was associated with major osteoporotic fractures (β = .288, P < .001) and hip fractures (β = .235, P < .001). Higher FSH was a risk factor for osteoporosis/osteopenia (odds ratios [OR] = 2.92, 95% CI = 1.66-5.14, P < .001), whereas higher E2 was a protective factor (OR = 0.37, 95% CI = 0.22-0.60, P < .001). Patients in the higher tertile of FSH and lower tertile of E2 had an increased risk of osteoporosis/osteopenia (OR = 5.05, 95% CI = 1.37-18.65, P < .05).

CONCLUSIONS

For males with T2DM, FSH and E2 are significantly associated with BMD, osteoporosis/osteopenia, and fracture risk.

Association of Serum Testosterone at 12 Years with a Subsequent Increase in Bone Mineral Apparent Density at 18 Years: A Longitudinal Study of Boys in Puberty

BACKGROUND

Cross-sectional studies have associated serum testosterone with bone mineral density (BMD). However, there is a shortage of prospective longitudinal studies in this domain, leaving it unclear whether changes in testosterone level precede changes in BMD.

OBJECTIVES

To examine the association between serum testosterone concentration at the age of 12 years and a subsequent increase in BMD by the age of 18 years.

METHODS

Eighty-eight boys with a mean age of 12.1 ± 0.7 (time point 1 [T1]) and 18.0 ± 0.7 (T2) were investigated. For both time points, serum testosterone was measured from venous blood samples. Total body (TB) and lumbar spine (LS) BMD and bone mineral apparent density (BMAD) were measured. As different brands of DEXA machines were used at T1 and T2, we calculated SD scores (SDS) from samples at T1 and T2 and their change (Δ). As covariates, bone age at T1 and physical activity (PA) by accelerometer at T1 and T2 were measured.

RESULTS

Serum testosterone at T1 was positively correlated with TB BMD at T2 (r = 0.28; p < 0.01), Δ TB BMAD SDS (r = 0.47; p < 0.0001) and Δ LS BMAD SDS (r = 0.23; p < 0.05). When additionally controlling for bone age and total PA at T1, the correlation between testosterone at T1 and Δ TB BMAD SDS remained significant (r = 0.32; p < 0.05).

CONCLUSIONS

Serum testosterone concentration at the age of 12 years is associated with a subsequent increase in TB BMAD by the age of 18 years. This supports the inference that testosterone levels in early puberty may influence subsequent bone mineral accrual.

The effects of testosterone on bone health in males with testosterone deficiency: a systematic review and meta-analysis

BACKGROUND

Testosterone deficiency (TD) may induce a series of clinical symptoms. Studies have shown that testosterone supplementation may prevent these unfavourable symptoms and improve patients' quality of life. Given the conflicting findings across studies, this systematic review aims to evaluate the effects and risks associated with testosterone supplementation in middle-aged or aging males with TD.

METHODS

Electronic databases (MEDLINE, EMBASE, PubMed, and Cochrane. Library were searched to December 2019. The risk of bias of individual included studies and the quality of the aggregate evidence were assessed using the GRADE approach. Our primary outcome was bone mineral density (BMD). Meta-analyses were performed. This systematic review was reported according to the PRISMA statement.

RESULTS

A total of 52 randomized controlled trials (RCTs) were included. When compared with placebo, testosterone supplementation did not increase total BMD (short-term: 1081 participants, MD - 0.01 g/cm², 95% CI - 0.02 g/cm² to 0.01 g/cm²; long-term: 156 participants, MD 0.04 g/cm², 95% CI - 0.07 g/cm² to 0.14 g/cm²), lumbar spine, hip, or femur neck BMD. Furthermore, testosterone supplementation did not decrease the risk of falling or fracture. Lastly, it was found that testosterone supplementation did not increase the risk of cardiovascular events (1374 participants, RR 1.28, 95% CI 0.62 to 2.64), all-cause mortality (729 participants, RR 0.55, 95% CI 0.29 to 1.04), or prostatic events. However, testosterone supplementation may improve sexual function and quality of life (1328 participants, MD -1.32, 95% CI - 2.11 to - 0.52).

CONCLUSIONS

The effect of testosterone supplementation on BMD and the risk of falls or fracture remains inconclusive. However, supplementation may benefit patients in the areas of sexual function and quality of life without increasing the risk of cardiovascular events, all-cause mortality, or prostatic events. RCTs with a longer follow-up period are still required.

TRIAL REGISTRATION

We registered our protocol in PROSPERO (CRD42018109738).

Increase in Osteocalcin Following Testosterone Therapy in Men With Type 2 Diabetes and Subnormal Free Testosterone

Context

One-third of men with type 2 diabetes have subnormal free testosterone concentrations. We evaluated the following: (i) whether bone mineral density (BMD) and bone strength are affected by gonadal status in type 2 diabetes and (ii) the effect of testosterone replacement on markers of osteoblast and osteoclast activity.

Design

This is a secondary analysis of a previously completed, randomized, placebo-controlled trial. Ninety-four men with type 2 diabetes were recruited; 44 had subnormal free testosterone concentrations. Men with subnormal free testosterone concentrations were randomized to receive intramuscular injections of testosterone or placebo every 2 weeks for 22 weeks. Dual energy X-ray absorptiometry scans were performed at baseline and at 23 weeks.

Results

Men with subnormal free testosterone had similar BMD compared with men with normal free testosterone. However, bone strength indices were lower in men with subnormal free testosterone. BMD was related to free estradiol concentrations (r = 0.37, P = 0.004 at hip), whereas bone strength was related to free testosterone concentrations (r = 0.41, P < 0.001). Testosterone replacement increased osteocalcin concentrations [mean change (95% CI), 3.52 (0.45, 6.59), P = 0.008]. C-Terminal telopeptide (CTx) concentrations also increased at 15 weeks but reverted to baseline following that. There were no changes in other bone turnover markers or BMD.

Conclusion

We conclude that testosterone replacement resulted in an increase in osteocalcin and a transient increase in CTx, indicating an increase in osteoblastic activity and transient increase in bone breakdown. Therefore, a major action of testosterone is to increase bone turnover in men with type 2 diabetes.

Male Obesity-related Secondary Hypogonadism - Pathophysiology, Clinical Implications and Management

The single most significant risk factor for testosterone deficiency in men is obesity. The pathophysiological mechanisms involved in male obesity-related secondary hypogonadism are highly complex. Obesity-induced increase in levels of leptin, insulin, proinflammatory cytokines and oestrogen can cause a functional hypogonadotrophic hypogonadism with the defect present at the level of the hypothalamic gonadotrophin-releasing hormone (GnRH) neurons. The resulting hypogonadism by itself can worsen obesity, creating a self-perpetuating cycle. Obesity-induced hypogonadism is reversible with substantial weight loss. Lifestyle-measures form the cornerstone of management as they can potentially improve androgen deficiency symptoms irrespective of their effect on testosterone levels. In selected patients, bariatric surgery can reverse the obesity-induced hypogonadism. If these measures fail to relieve symptoms and to normalise testosterone levels, in appropriately selected men, testosterone replacement therapy could be started. Aromatase inhibitors and selective oestrogen receptor modulators are not recommended due to lack of consistent clinical trial-based evidence.