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The Testosterone Trials (TTrials) were a coordinated set of seven placebo-controlled, double-blind trials in 788 men with a mean age of 72 years to determine the efficacy of increasing the testosterone levels of older men with low testosterone. Testosterone treatment increased the median testosterone level from unequivocally low at baseline to midnormal for young men after 3 months and maintained that level until month 12. In the Sexual Function Trial, testosterone increased sexual activity, sexual desire, and erectile function. In the Physical Function Trial, testosterone did not increase the distance walked in 6 minutes in men whose walk speed was slow; however, in all TTrial participants, testosterone did increase the distance walked. In the Vitality Trial, testosterone did not increase energy but slightly improved mood and depressive symptoms. In the Cognitive Function Trial, testosterone did not improve cognitive function. In the Anemia Trial, testosterone increased hemoglobin in both men who had anemia of a known cause and in men with unexplained anemia. In the Bone Trial, testosterone increased volumetric bone mineral density and the estimated strength of the spine and hip. In the Cardiovascular Trial, testosterone increased the coronary artery noncalcified plaque volume as assessed using computed tomographic angiography. Although testosterone was not associated with more cardiovascular or prostate adverse events than placebo, a trial of a much larger number of men for a much longer period would be necessary to determine whether testosterone increases cardiovascular or prostate risk.

Background: Decline in serum androgens is common among older men and has been associated with cardiovascular disease, although its role in risk of atrial fibrillation (AF) has not been well defined., Hypothesis: Low serum androgens are associated with an increased risk of AF., Methods: We examined the prospective associations between testosterone, its more active metabolite dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) with risk of AF among 1019 otherwise healthy men with average age 76.3 ±4.9 years in the Cardiovascular Health Study., Results: After median follow-up of 9.5 years, 304 (30%) men developed AF. We detected a nonlinear association with risk of incident AF in both free and total DHT, in which subjects with the lowest levels had a higher risk of incident AF. After adjustment for demographics, clinical risk factors, left atrial diameter, and serum NT-proBNP levels, men with free DHT <0.16 ng/dL were at increased risk compared with men with higher levels (hazard ratio: 1.48, 95% confidence interval: 1.01-2.17, P <0.05). Sensitivity analyses confirmed that the increased risk was not cutpoint-specific, with a significant association noted up to cutpoints <~0.2 ng/dL. We also detected a complex nonlinear association between SHBG and incident AF, in which subjects in the middle quintile (52.9-65.3 nmol/L) had increased risk., Conclusions: Among older men, low free DHT is associated with an increased risk of incident AF. Further studies are needed to explore mechanisms for this association., (© 2018 Wiley Periodicals, Inc.)

Objective: To update the "Testosterone Therapy in Men With Androgen Deficiency Syndromes" guideline published in 2010., Participants: The participants include an Endocrine Society-appointed task force of 10 medical content experts and a clinical practice guideline methodologist., Evidence: This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies., Consensus Process: One group meeting, several conference calls, and e-mail communications facilitated consensus development. Endocrine Society committees and members and the cosponsoring organization were invited to review and comment on preliminary drafts of the guideline., Conclusions: We recommend making a diagnosis of hypogonadism only in men with symptoms and signs consistent with testosterone (T) deficiency and unequivocally and consistently low serum T concentrations. We recommend measuring fasting morning total T concentrations using an accurate and reliable assay as the initial diagnostic test. We recommend confirming the diagnosis by repeating the measurement of morning fasting total T concentrations. In men whose total T is near the lower limit of normal or who have a condition that alters sex hormone-binding globulin, we recommend obtaining a free T concentration using either equilibrium dialysis or estimating it using an accurate formula. In men determined to have androgen deficiency, we recommend additional diagnostic evaluation to ascertain the cause of androgen deficiency. We recommend T therapy for men with symptomatic T deficiency to induce and maintain secondary sex characteristics and correct symptoms of hypogonadism after discussing the potential benefits and risks of therapy and of monitoring therapy and involving the patient in decision making. We recommend against starting T therapy in patients who are planning fertility in the near term or have any of the following conditions: breast or prostate cancer, a palpable prostate nodule or induration, prostate-specific antigen level > 4 ng/mL, prostate-specific antigen > 3 ng/mL in men at increased risk of prostate cancer (e.g., African Americans and men with a first-degree relative with diagnosed prostate cancer) without further urological evaluation, elevated hematocrit, untreated severe obstructive sleep apnea, severe lower urinary tract symptoms, uncontrolled heart failure, myocardial infarction or stroke within the last 6 months, or thrombophilia. We suggest that when clinicians institute T therapy, they aim at achieving T concentrations in the mid-normal range during treatment with any of the approved formulations, taking into consideration patient preference, pharmacokinetics, formulation-specific adverse effects, treatment burden, and cost. Clinicians should monitor men receiving T therapy using a standardized plan that includes: evaluating symptoms, adverse effects, and compliance; measuring serum T and hematocrit concentrations; and evaluating prostate cancer risk during the first year after initiating T therapy.

Context: Studies of the possible cardiovascular risk of testosterone treatment are inconclusive., Objective: To determine the effect of testosterone treatment on cardiovascular biomarkers in older men with low testosterone., Design: Double-blind, placebo-controlled trial., Setting: Twelve academic medical centers in the United States., Participants: In all, 788 men ≥65 years old with an average of two serum testosterone levels <275 ng/dL who were enrolled in The Testosterone Trials., Intervention: Testosterone gel, the dose adjusted to maintain the testosterone level in the normal range for young men, or placebo gel for 12 months., Main Outcome Measures: Serum markers of cardiovascular risk, including lipids and markers of glucose metabolism, fibrinolysis, inflammation, and myocardial damage., Results: Compared with placebo, testosterone treatment significantly decreased total cholesterol (adjusted mean difference, -6.1 mg/dL; P < 0.001), high-density lipoprotein cholesterol (adjusted mean difference, -2.0 mg/dL; P < 0.001), and low-density lipoprotein cholesterol (adjusted mean difference, -2.3 mg/dL; P = 0.051) from baseline to month 12. Testosterone also slightly but significantly decreased fasting insulin (adjusted mean difference, -1.7 µIU/mL; P = 0.02) and homeostatic model assessment‒insulin resistance (adjusted mean difference, -0.6; P = 0.03). Testosterone did not change triglycerides, d-dimer, C-reactive protein, interleukin 6, troponin, glucose, or hemoglobin A1c levels more than placebo., Conclusions and Relevance: Testosterone treatment of 1 year in older men with low testosterone was associated with small reductions in cholesterol and insulin but not with other glucose markers, markers of inflammation or fibrinolysis, or troponin. The clinical importance of these findings is unclear and requires a larger trial of clinical outcomes., (Copyright © 2017 Endocrine Society)

Fall prevention is an important way to prevent fractures in person with osteoporosis. We developed and implemented a fall screening program in the context of routine osteoporosis care. This program was found to be feasible and showed that a significant proportion of persons with osteoporosis are at risk of falling., Purpose: Falls are the most common cause of fracture in persons with osteoporosis. However, osteoporosis care rarely includes assessment and prevention of falling. We thus sought to assess the feasibility of a fall screening and management program integrated into routine osteoporosis care., Methods: The program was developed and offered to patients with osteoporosis or osteopenia seen at an outpatient clinic between May 2015 and May 2016. Feasibility was measured by physical therapist time required to conduct screening and ease of integrating the screening program into the usual clinic workflow. Self-report responses and mobility testing were conducted to describe the fall and fracture risk profile of osteoporosis patients screened. Effects on fall-related care processes were assessed via chart abstraction of patient participation in fall prevention exercise., Results: Of the 154 clinic patients who presented for a clinic visit, 68% met screening criteria and completed in two thirds of persons. Screening was completed in a third of the time typically allotted for traditional PT evaluations and did not interfere with clinic workflow. Forty percent of those screened reported falling in the last year, and over half had two or more falls in the past year. Over half reported a balance or lower extremity impairment, and over 40% were below norms on one or more performance tests. Most patients who selected a group exercise fall prevention program completed all sessions while only a quarter completed either supervised or independent home-based programs., Conclusions: Implementation of a fall risk screening program in an outpatient osteoporosis clinic appears feasible. A substantial proportion of people with osteoporosis screened positive for being at risk of falling, justifying integration of fall prevention into routine osteoporosis care.

KEY POINTS Falls are a major health issue for older adults, leading to adverse events and even death. Older persons with type 2 diabetes are at increased risk of falling compared to healthy adults of a similar age. Over 400 factors are associated with falls risk, making identification and targeting of key factors to prevent falls problematic. However, the major risk factors include hypertension, diabetes, pain, and polypharmacy. In addition to age and polypharmacy, diabetes-related loss of strength, sensory perception, and balance secondary to peripheral neuropathy along with decline in cognitive function lead to increased risk of falling. Designing specific interventions to target strength and balance training, reducing polypharmacy to improve cognitive function, relaxation of diabetes management to avoid hypoglycemia and hypotension, and relief of pain will produce the greatest benefit for reducing falls in older persons with diabetes. Abbreviation: DPN = diabetic polyneuropathy.

Sarcopenia is defined as low muscle function (walking speed or grip strength) in the presence of low muscle mass. A simple screening test-the SARC-F-is available to identify persons with sarcopenia. The major endocrine causes of sarcopenia are diabetes mellitus and male hypogonadism. Other causes are decreased physical activity, loss of motor neuron units, weight loss, inflammatory cytokines, reduced blood flow to muscles, very low 25(OH) vitamin D levels, and decreased growth hormone and insulin-like growth factor 1. Treatment for sarcopenia includes resistance and aerobic exercise, leucine-enriched essential amino acids, and vitamin D. In hypogonadal males, testosterone improves muscle mass, strength, and function. Selective androgen receptor molecules and anti-myostatin activin II receptor molecules are under development as possible treatments for sarcopenia., Abbreviations: COPD = chronic obstructive pulmonary disease DHEA = dehydroepiandrosterone IGF-1 = insulin-like growth factor 1 GH = growth hormone mTOR = mammalian target of rapamycin SARM = selective androgen receptor molecule.

Purpose: Germline variation in solute carrier organic anion ( SLCO ) genes influences cellular steroid uptake and is associated with prostate cancer outcomes. We hypothesized that, due to its steroidal structure, the CYP17A inhibitor abiraterone may undergo transport by SLCO -encoded transporters and that SLCO gene variation may influence intracellular abiraterone levels and outcomes. Experimental Design: Steroid and abiraterone levels were measured in serum and tissue from 58 men with localized prostate cancer in a clinical trial of LHRH agonist plus abiraterone acetate plus prednisone for 24 weeks prior to prostatectomy. Germline DNA was genotyped for 13 SNPs in six SLCO genes. Results: Abiraterone levels spanned a broad range (serum median 28 ng/mL, 108 nmol/L; tissue median 77 ng/mL, 271 nmol/L) and were correlated ( r = 0.355, P = 0.001). Levels correlated positively with steroids upstream of CYP17A (pregnenolone, progesterone), and inversely with steroids downstream of CYP17A (DHEA, AED, testosterone). Serum PSA and tumor volumes were higher in men with undetectable versus detectable tissue abiraterone at prostatectomy (median 0.10 vs. 0.03 ng/dL, P = 0.02; 1.28 vs. 0.44 cc, P = 0.09, respectively). SNPs in SLCO2B1 associated with significant differences in tissue abiraterone (rs1789693, P = 0.0008; rs12422149, P = 0.03) and higher rates of minimal residual disease (tumor volume < 0.5 cc; rs1789693, 67% vs. 27%, P = 0.009; rs1077858, 46% vs. 0%, P = 0.03). LNCaP cells expressing SLCO2B1 showed two- to fourfold higher abiraterone levels compared with vector controls ( P < 0.05). Conclusions: Intraprostatic abiraterone levels and genetic variation in SLCO genes are associated with pathologic responses in high-risk localized prostate cancer. Variation in SLCO genes may serve as predictors of response to abiraterone treatment. Clin Cancer Res; 23(16); 4592-601. ©2017 AACR ., (©2017 American Association for Cancer Research.)

In the circulation, testosterone and other sex hormones are bound to binding proteins, which play an important role in regulating their transport, distribution, metabolism, and biological activity. According to the free hormone hypothesis, which has been debated extensively, only the unbound or free fraction is biologically active in target tissues. Consequently, accurate determination of the partitioning of testosterone between bound and free fractions is central to our understanding of how its delivery to the target tissues and biological activity are regulated and consequently to the diagnosis and treatment of androgen disorders in men and women. Here, we present a historical perspective on the evolution of our understanding of the binding of testosterone to circulating binding proteins. On the basis of an appraisal of the literature as well as experimental data, we show that the assumptions of stoichiometry, binding dynamics, and the affinity of the prevailing models of testosterone binding to sex hormone-binding globulin and human serum albumin are not supported by published experimental data and are most likely inaccurate. This review offers some guiding principles for the application of free testosterone measurements in the diagnosis and treatment of patients with androgen disorders. The growing number of testosterone prescriptions and widely recognized problems with the direct measurement as well as the computation of free testosterone concentrations render this critical review timely and clinically relevant., (Copyright © 2017 Endocrine Society.)

Objective: Serum sex steroid concentrations may alter body composition and glucose homoeostasis in men in a dose-response manner. We evaluated these end-points in healthy men rendered medically castrate through use of a gonadotrophin-releasing hormone antagonist (acyline) with incremental doses of exogenous testosterone (T) gel., Design: Subjects (n=6-9 per group) were randomly assigned to injections of acyline every 2 weeks plus transdermal T gel (1.25 g, 2.5 g, 5.0 g, 10 g or 15 g) daily or double placebo (injections and gel) for 12 weeks., Patients: Healthy men, ages 25-55 years, with normal serum total T concentrations., Measurements: Serum T, dihydrotestosterone (DHT) and oestradiol (E2) were measured at baseline and every 2 weeks. Body composition was analysed by dual-energy X-ray absorptiometry at baseline and week 12. Fasting serum adiponectin, leptin, glucose and insulin concentrations were measured at baseline and week 10., Results: Forty-eight men completed the study. A significant treatment effect was observed for change in lean mass (ANOVAP=.01) but not fat mass (P=.14). Lean mass increased in the 15 g T group relative to all lower dose groups, except the 10 g T group. When all subjects were analysed together, changes in lean mass correlated directly and changes in fat mass correlated inversely with serum T, E2 and DHT. No changes were noted in serum glucose, insulin or adipokine levels., Conclusions: In healthy men, higher serum concentrations of T, DHT and E2 were associated with greater increases in lean mass and decreases in fat mass but not with changes in serum glucose, insulin or adipokines., (© 2017 John Wiley & Sons Ltd.)

Purpose: Prostate cancer is dependent on androgen receptor (AR) activation. Optimal AR antagonism may effectively cytoreduce local disease and suppress or eliminate micrometastases. We evaluated neoadjuvant therapy prior to prostatectomy with the potent AR antagonist enzalutamide (enza) either alone or in combination with dutasteride (dut) and leuprolide (enza/dut/luteinizing hormone-releasing hormone analogues [LHRHa]). Experimental Design: Forty-eight of 52 men with intermediate or high-risk localized prostate cancer proceeded to prostatectomy after neoadjuvant enzalutamide or enza/dut/LHRHa for 6 months. We assessed pathologic complete response (pCR), minimal residual disease (MRD; ≤3 mm maximum diameter of residual disease), residual cancer burden (RCB), and expression of PSA and serum and tissue androgen concentrations. We compared the proportion of patients with pCR in each treatment arm with a historical control rate of 5%, based on previous reports of flutamide with LHRHa. Results: In the enzalutamide arm, none of the 25 patients achieved pCR or MRD. In the enza/dut/LHRHa arm, one of 23 patients (4.3%) achieved pCR and 3 of 23 (13.0%) achieved MRD. Median RCB was higher in the enzalutamide arm than in the enza/dut/LHRHa arm (0.41 cm 3 vs. 0.06 cm 3 , respectively). Tissue testosterone and dihydrotestosterone levels correlated with RCB. No adverse events leading to study drug discontinuation were reported. Conclusions: Combination therapy with enza/dut/LHRHa resulted in pCR and MRD rates comparable with historical controls. Evidence of continued AR activity in residual tumor suggests that AR signaling may contribute to survival. Strategies to more effectively ablate AR activity are warranted to determine whether more substantial antitumor effects are observed. Clin Cancer Res; 23(9); 2169-76. ©2016 AACR ., (©2016 American Association for Cancer Research.)

Importance: In one-third of older men with anemia, no recognized cause can be found., Objective: To determine if testosterone treatment of men 65 years or older with unequivocally low testosterone levels and unexplained anemia would increase their hemoglobin concentration., Design, Setting, and Participants: A double-blinded, placebo-controlled trial with treatment allocation by minimization using 788 men 65 years or older who have average testosterone levels of less than 275 ng/dL. Of 788 participants, 126 were anemic (hemoglobin ≤12.7 g/dL), 62 of whom had no known cause. The trial was conducted in 12 academic medical centers in the United States from June 2010 to June 2014., Interventions: Testosterone gel, the dose adjusted to maintain the testosterone levels normal for young men, or placebo gel for 12 months., Main Outcomes and Measures: The percent of men with unexplained anemia whose hemoglobin levels increased by 1.0 g/dL or more in response to testosterone compared with placebo. The statistical analysis was intent-to-treat by a logistic mixed effects model adjusted for balancing factors., Results: The men had a mean age of 74.8 years and body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) of 30.7; 84.9% were white. Testosterone treatment resulted in a greater percentage of men with unexplained anemia whose month 12 hemoglobin levels had increased by 1.0 g/dL or more over baseline (54%) than did placebo (15%) (adjusted OR, 31.5; 95% CI, 3.7-277.8; P = .002) and a greater percentage of men who at month 12 were no longer anemic (58.3%) compared with placebo (22.2%) (adjusted OR, 17.0; 95% CI, 2.8-104.0; P = .002). Testosterone treatment also resulted in a greater percentage of men with anemia of known cause whose month 12 hemoglobin levels had increased by 1.0 g/dL or more (52%) than did placebo (19%) (adjusted OR, 8.2; 95% CI, 2.1-31.9; P = .003). Testosterone treatment resulted in a hemoglobin concentration of more than 17.5 g/dL in 6 men who had not been anemic at baseline., Conclusions and Relevance: Among older men with low testosterone levels, testosterone treatment significantly increased the hemoglobin levels of those with unexplained anemia as well as those with anemia from known causes. These increases may be of clinical value, as suggested by the magnitude of the changes and the correction of anemia in most men, but the overall health benefits remain to be established. Measurement of testosterone levels might be considered in men 65 years or older who have unexplained anemia and symptoms of low testosterone levels., Trial Registration: clinicaltrials.gov Identifier: NCT00799617.

Importance: As men age, they experience decreased serum testosterone concentrations, decreased bone mineral density (BMD), and increased risk of fracture., Objective: To determine whether testosterone treatment of older men with low testosterone increases volumetric BMD (vBMD) and estimated bone strength., Design, Setting, and Participants: Placebo-controlled, double-blind trial with treatment allocation by minimization at 9 US academic medical centers of men 65 years or older with 2 testosterone concentrations averaging less than 275 ng/L participating in the Testosterone Trials from December 2011 to June 2014. The analysis was a modified intent-to-treat comparison of treatment groups by multivariable linear regression adjusted for balancing factors as required by minimization., Interventions: Testosterone gel, adjusted to maintain the testosterone level within the normal range for young men, or placebo gel for 1 year., Main Outcomes and Measures: Spine and hip vBMD was determined by quantitative computed tomography at baseline and 12 months. Bone strength was estimated by finite element analysis of quantitative computed tomography data. Areal BMD was assessed by dual energy x-ray absorptiometry at baseline and 12 months., Results: There were 211 participants (mean [SD] age, 72.3 [5.9] years; 86% white; mean [SD] body mass index, 31.2 [3.4]). Testosterone treatment was associated with significantly greater increases than placebo in mean spine trabecular vBMD (7.5%; 95% CI, 4.8% to 10.3% vs 0.8%; 95% CI, -1.9% to 3.4%; treatment effect, 6.8%; 95% CI, 4.8%-8.7%; P < .001), spine peripheral vBMD, hip trabecular and peripheral vBMD, and mean estimated strength of spine trabecular bone (10.8%; 95% CI, 7.4% to 14.3% vs 2.4%; 95% CI, -1.0% to 5.7%; treatment effect, 8.5%; 95% CI, 6.0%-10.9%; P < .001), spine peripheral bone, and hip trabecular and peripheral bone. The estimated strength increases were greater in trabecular than peripheral bone and greater in the spine than hip. Testosterone treatment increased spine areal BMD but less than vBMD., Conclusions and Relevance: Testosterone treatment for 1 year of older men with low testosterone significantly increased vBMD and estimated bone strength, more in trabecular than peripheral bone and more in the spine than hip. A larger, longer trial could determine whether this treatment also reduces fracture risk., Trial Registration: clinicaltrials.gov Identifier: NCT00799617.

Background: Reference ranges for testosterone are essential for making a diagnosis of hypogonadism in men., Objective: To establish harmonized reference ranges for total testosterone in men that can be applied across laboratories by cross-calibrating assays to a reference method and standard., Population: The 9054 community-dwelling men in cohort studies in the United States and Europe: Framingham Heart Study; European Male Aging Study; Osteoporotic Fractures in Men Study; and Male Sibling Study of Osteoporosis., Methods: Testosterone concentrations in 100 participants in each of the four cohorts were measured using a reference method at Centers for Disease Control and Prevention (CDC). Generalized additive models and Bland-Altman analyses supported the use of normalizing equations for transformation between cohort-specific and CDC values. Normalizing equations, generated using Passing-Bablok regression, were used to generate harmonized values, which were used to derive standardized, age-specific reference ranges., Results: Harmonization procedure reduced intercohort variation between testosterone measurements in men of similar ages. In healthy nonobese men, 19 to 39 years, harmonized 2.5th, 5th, 50th, 95th, and 97.5th percentile values were 264, 303, 531, 852, and 916 ng/dL, respectively. Age-specific harmonized testosterone concentrations in nonobese men were similar across cohorts and greater than in all men., Conclusion: Harmonized normal range in a healthy nonobese population of European and American men, 19 to 39 years, is 264 to 916 ng/dL. A substantial proportion of intercohort variation in testosterone levels is due to assay differences. These data demonstrate the feasibility of generating harmonized reference ranges for testosterone that can be applied to assays, which have been calibrated to a reference method and calibrator., (Copyright © 2017 by the Endocrine Society)

Context: Middle-aged and older men (≥50 years), especially those who are obese and suffer from comorbidities, not uncommonly present with clinical features consistent with androgen deficiency and modestly reduced testosterone levels. Commonly, such men do not demonstrate anatomical hypothalamic-pituitary-testicular axis pathology but have functional hypogonadism that is potentially reversible., Evidence Acquisition: Literature review from 1970 to October 2016., Evidence Synthesis: Although definitive randomized controlled trials are lacking, evidence suggests that in such men, lifestyle measures to achieve weight loss and optimization of comorbidities, including discontinuation of offending medications, lead to clinical improvement and a modest increase in testosterone. Also, androgen deficiency-like symptoms and end-organ deficits respond to targeted treatments (such as phosphodiesterase-5 inhibitors for erectile dysfunction) without evidence that hypogonadal men are refractory. Unfortunately, lifestyle interventions remain difficult and may be insufficient even if successful. Testosterone therapy should be considered primarily for men who have significant clinical features of androgen deficiency and unequivocally low testosterone levels. Testosterone should be initiated either concomitantly with a trial of lifestyle measures, or after such a trial fails, after a tailored diagnostic work-up, exclusion of contraindications, and appropriate counseling., Conclusions: There is modest evidence that functional hypogonadism responds to lifestyle measures and optimization of comorbidities. If achievable, these interventions may have demonstrable health benefits beyond the potential for increasing testosterone levels. Therefore, treatment of underlying causes of functional hypogonadism and of symptoms should be used either as an initial or adjunctive approach to testosterone therapy.

Importance: Most cognitive functions decline with age. Prior studies suggest that testosterone treatment may improve these functions., Objective: To determine if testosterone treatment compared with placebo is associated with improved verbal memory and other cognitive functions in older men with low testosterone and age-associated memory impairment (AAMI)., Design, Setting, and Participants: The Testosterone Trials (TTrials) were 7 trials to assess the efficacy of testosterone treatment in older men with low testosterone levels. The Cognitive Function Trial evaluated cognitive function in all TTrials participants. In 12 US academic medical centers, 788 men who were 65 years or older with a serum testosterone level less than 275 ng/mL and impaired sexual function, physical function, or vitality were allocated to testosterone treatment (n = 394) or placebo (n = 394). A subgroup of 493 men met criteria for AAMI based on baseline subjective memory complaints and objective memory performance. Enrollment in the TTrials began June 24, 2010; the final participant completed treatment and assessment in June 2014., Interventions: Testosterone gel (adjusted to maintain the testosterone level within the normal range for young men) or placebo gel for 1 year., Main Outcomes and Measures: The primary outcome was the mean change from baseline to 6 months and 12 months for delayed paragraph recall (score range, 0 to 50) among men with AAMI. Secondary outcomes were mean changes in visual memory (Benton Visual Retention Test; score range, 0 to -26), executive function (Trail-Making Test B minus A; range, -290 to 290), and spatial ability (Card Rotation Test; score range, -80 to 80) among men with AAMI. Tests were administered at baseline, 6 months, and 12 months., Results: Among the 493 men with AAMI (mean age, 72.3 years [SD, 5.8]; mean baseline testosterone, 234 ng/dL [SD, 65.1]), 247 were assigned to receive testosterone and 246 to receive placebo. Of these groups, 247 men in the testosterone group and 245 men in the placebo completed the memory study. There was no significant mean change from baseline to 6 and 12 months in delayed paragraph recall score among men with AAMI in the testosterone and placebo groups (adjusted estimated difference, -0.07 [95% CI, -0.92 to 0.79]; P = .88). Mean scores for delayed paragraph recall were 14.0 at baseline, 16.0 at 6 months, and 16.2 at 12 months in the testosterone group and 14.4 at baseline, 16.0 at 6 months, and 16.5 at 12 months in the placebo group. Testosterone was also not associated with significant differences in visual memory (-0.28 [95% CI, -0.76 to 0.19]; P = .24), executive function (-5.51 [95% CI, -12.91 to 1.88]; P = .14), or spatial ability (-0.12 [95% CI, -1.89 to 1.65]; P = .89)., Conclusions and Relevance: Among older men with low testosterone and age-associated memory impairment, treatment with testosterone for 1 year compared with placebo was not associated with improved memory or other cognitive functions., Trial Registration: clinicaltrials.gov Identifier: NCT00799617.

Importance: Recent studies have yielded conflicting results as to whether testosterone treatment increases cardiovascular risk., Objective: To test the hypothesis that testosterone treatment of older men with low testosterone slows progression of noncalcified coronary artery plaque volume., Design, Setting, and Participants: Double-blinded, placebo-controlled trial at 9 academic medical centers in the United States. The participants were 170 of 788 men aged 65 years or older with an average of 2 serum testosterone levels lower than 275 ng/dL (82 men assigned to placebo, 88 to testosterone) and symptoms suggestive of hypogonadism who were enrolled in the Testosterone Trials between June 24, 2010, and June 9, 2014., Intervention: Testosterone gel, with the dose adjusted to maintain the testosterone level in the normal range for young men, or placebo gel for 12 months., Main Outcomes and Measures: The primary outcome was noncalcified coronary artery plaque volume, as determined by coronary computed tomographic angiography. Secondary outcomes included total coronary artery plaque volume and coronary artery calcium score (range of 0 to >400 Agatston units, with higher values indicating more severe atherosclerosis)., Results: Of 170 men who were enrolled, 138 (73 receiving testosterone treatment and 65 receiving placebo) completed the study and were available for the primary analysis. Among the 138 men, the mean (SD) age was 71.2 (5.7) years, and 81% were white. At baseline, 70 men (50.7%) had a coronary artery calcification score higher than 300 Agatston units, reflecting severe atherosclerosis. For the primary outcome, testosterone treatment compared with placebo was associated with a significantly greater increase in noncalcified plaque volume from baseline to 12 months (from median values of 204 mm3 to 232 mm3 vs 317 mm3 to 325 mm3, respectively; estimated difference, 41 mm3; 95% CI, 14 to 67 mm3; P = .003). For the secondary outcomes, the median total plaque volume increased from baseline to 12 months from 272 mm3 to 318 mm3 in the testosterone group vs from 499 mm3 to 541 mm3 in the placebo group (estimated difference, 47 mm3; 95% CI, 13 to 80 mm3; P = .006), and the median coronary artery calcification score changed from 255 to 244 Agatston units in the testosterone group vs 494 to 503 Agatston units in the placebo group (estimated difference, -27 Agatston units; 95% CI, -80 to 26 Agatston units). No major adverse cardiovascular events occurred in either group., Conclusions and Relevance: Among older men with symptomatic hypogonadism, treatment with testosterone gel for 1 year compared with placebo was associated with a significantly greater increase in coronary artery noncalcified plaque volume, as measured by coronary computed tomographic angiography. Larger studies are needed to understand the clinical implications of this finding., Trial Registration: clinicaltrials.gov Identifier: NCT00799617.

Purpose: Despite the efficacy of abiraterone, a CYP17A1 inhibitor, in metastatic castration-resistant prostate cancer (CRPC), nearly all patients develop resistance. The purpose of this phase II study was to evaluate mechanisms of resistance to more complete androgen synthesis inhibition with abiraterone and dutasteride. Experimental Design: Eligible patients with metastatic CRPC underwent a baseline metastasis biopsy. Patients received abiraterone and prednisone for two 4-week cycles. After this time, high-dose dutasteride (3.5 mg daily) was added. Patients continued therapy until study withdrawal or radiographic progression. Repeat metastasis biopsy was obtained at progression. The primary endpoint was to assess mechanisms of resistance. Serum hormone and abiraterone levels were assessed. Tissue was assessed for androgen receptor (AR) and AR splice variant-7 (ARV7) expression. Results: Forty patients were enrolled. Sixty percent ( n = 24) achieved a ≥50% reduction in prostate-specific antigen (PSA). The median time to radiographic progression was 11 months. Nearly all baseline ( n = 29 of 31) and posttreatment ( n = 16 of 16) tumors tested for AR nuclear expression were positive. Of those tested, ARV7 expression was present in 48% ( n = 10 of 21) of baseline and 42% ( n = 5 of 12) of treatment discontinuation specimens. Compared with patients with higher serum abiraterone levels at treatment discontinuation, patients with lower levels had higher circulating androgens. Conclusions: Despite increased androgen synthesis inhibition, we demonstrate that tumor AR axis remains important in disease progression. We highlight that abiraterone metabolism and pharmacokinetics may play a role in resistance. The noncomparative design limits conclusions on the efficacy of dual therapy with abiraterone and dutasteride, but the results support development of further multifaceted approaches toward AR inhibition. Clin Cancer Res; 23(4); 935-45. ©2016 AACR ., (©2016 American Association for Cancer Research.)

Context: Although sex hormone-binding globulin (SHBG) and testosterone (T) have been inversely associated with risk of diabetes, few studies have examined dihydrotestosterone (DHT), a more potent androgen than T, in older adults, whose glycemic pathophysiology differs from younger adults., Objective: To determine the associations of SHBG, T, and DHT with insulin resistance and incident diabetes in older adult men., Design: In a prospective cohort study, we evaluated baseline levels of SHBG, T, and DHT using liquid chromatography-tandem mass spectrometry among 852 men free of diabetes and cardiovascular disease in the Cardiovascular Health Study in 1994., Main Outcome: Insulin resistance estimated by Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and insulin sensitivity estimated by the Gutt index in 1996, and incident diabetes (n = 112) ascertained over a mean follow-up of 9.8 years., Results: In linear regression models adjusted for demographics, alcohol consumption, current smoking, body mass index, and other androgens, SHBG [HOMA-IR 0.30 units lower per doubling; 95% confidence interval (CI), 0.08 to 0.52; P = 0.01] and total DHT (HOMA-IR 0.18 units lower per doubling; 95% CI, 0.06 to 0.30; P = 0.01), but not free T (P = 0.33), were inversely associated with insulin resistance. In corresponding Cox proportional hazards models, total DHT was again inversely associated with risk of diabetes (adjusted hazard ratio per doubling, 0.69; 95% CI, 0.52 to 0.92; P = 0.01), but SHBG (hazard ratio, 1.09; 95% CI, 0.74 to 1.59; P = 0.66) and free T (hazard ratio, 1.15; 95% CI, 0.92 to 1.43; P = 0.23) were not., Conclusions: Among older men, higher levels of DHT were inversely associated with insulin resistance and risk of diabetes over the ensuing 10 years, whereas levels of T were not. Future studies are still needed to clarify the role of SHBG in risk of diabetes in this population., (Copyright © 2017 by the Endocrine Society)

Objective: To review the doping status of dehydroepiandrosterone (DHEA) for female athletes with adrenal insufficiency within the framework of Therapeutic Use Exemption (TUE) applications for this proandrogen, which is included on the World Anti-Doping Agency (WADA)'s Prohibited List., Data Sources and Main Results: Current knowledge of adrenal pathophysiology with a focus on the physiological role and pharmacological effects of DHEA in female athletes including placebo-controlled clinical trials of DHEA and consensus clinical practice and prescribing guidelines., Conclusions: Because there is no convincing clinical evidence to support the use of DHEA replacement therapy in women with adrenal failure, a TUE for DHEA is not justified by definite health benefit for either secondary or primary adrenal failure. This is consistent with the 2014 update of the US Endocrine Society guidelines, meta-analyses of DHEA treatment in women with or without adrenal failure, current WADA TUE guidance document for adrenal insufficiency and recent case law of WADA's Court of Arbitration for Sport.

Problem: The role of plasma estradiol in the accumulation of intra-abdominal fat (IAF) in men is uncertain. Cross-sectional studies using imaging of IAF have shown either a positive or no association. In contrast, a randomised controlled trial using an aromatase inhibitor to suppress estradiol production found an association between oestrogen deficiency and short-term IAF accumulation. No longitudinal study has been conducted to examine the relationship between plasma estradiol concentration and the change in IAF area measured using direct imaging., Methods: This is a longitudinal observational study in community-dwelling Japanese-American men (n=215, mean age 52 years, BMI 25.4kg/m 2 ). IAF and subcutaneous fat areas were assessed using computerized tomography (CT) at baseline, 5 and 10 years. Baseline plasma estradiol concentrations were measured using liquid chromatography-tandem mass spectrometry., Results: Univariate analysis found no association between baseline estradiol concentration and baseline IAF, or 5- or 10-year changes in IAF area (r=-0.05 for both time points, p=0.45 and p=0.43, respectively). Multivariate linear regression analysis of the change in IAF area by baseline estradiol concentration adjusted for age, baseline IAF area, and weight change found no association with either the 5- or 10-year IAF area change (p=0.52 and p=0.55, respectively)., Conclusions: Plasma estradiol concentration was not associated with baseline IAF nor with change in IAF area over 5 or 10 years based on serial CT scans in community-dwelling Japanese-American men. These results do not support a role for oestrogen deficiency in IAF accumulation in men., Competing Interests: None., (Copyright © 2015 Asia Oceania Association for the Study of Obesity. All rights reserved.)

Context: T deprivation increases risk of insulin resistance in men, but whether this risk is independent of changes in body composition is unknown. Further, the metabolic roles of T and its metabolite estradiol have not been clearly defined in men., Objective: This study sought to establish the effects of selective sex steroid withdrawal on insulin sensitivity in healthy men., Design, Setting, and Participants: This was a double-blinded, placebo-controlled, randomized trial at an academic medical center of 56 healthy men, 19-55 years of age., Interventions: Subjects received the GnRH antagonist acyline plus one of the following: placebo gel (Castrate), 1.25 g testosterone gel (Low T/E), 5 g testosterone gel (Normal T/E), or 5 g testosterone gel with letrozole (Normal T/Low E) daily for 4 weeks. Body composition and glucose tolerance were assessed at baseline and end of treatment., Main Outcome Measure: Insulin sensitivity was quantified by the Matsuda index., Results: Predicted circulating sex steroid concentrations were achieved in all treatment groups. The time-by-group interaction for Matsuda index did not achieve significance in overall repeated measures ANOVA (baseline vs week 4; P = .16). A significant time-by-group interaction was observed for fat mass (P = .003), with changes in fat mass attributable predominantly to estrogen exposure in linear regression analysis (P = .016). A time-by-group interaction also was observed for lean mass (P = .03) and influenced by androgen exposure (P = .003)., Conclusions: Short-term sex steroid withdrawal in healthy men causes adverse changes in body composition. These findings support the role of estradiol as a determinant of adiposity in men.

Context: The Testosterone Trials are a coordinated set of seven trials to determine the efficacy of T in symptomatic men ≥65 years old with unequivocally low T levels. Initial results of the Sexual Function Trial showed that T improved sexual activity, sexual desire, and erectile function., Objective: To assess the responsiveness of specific sexual activities to T treatment; to relate hormone changes to changes in sexual function; and to determine predictive baseline characteristics and T threshold for sexual outcomes., Design: A placebo-controlled trial., Setting: Twelve academic medical centers in the United States., Participants: A total of 470 men ≥65 years of age with low libido, average T <275 ng/dL, and a partner willing to have sexual intercourse at least twice a month., Methods: Men were assigned to take T gel or placebo for 1 year. Sexual function was assessed by three questionnaires every 3 months: the Psychosexual Daily Questionnaire, the Derogatis Interview for Sexual Function, and the International Index of Erectile Function., Results: Compared with placebo, T administration significantly improved 10 of 12 measures of sexual activity. Incremental increases in total and free T and estradiol levels were associated with improvements in sexual activity and desire, but not erectile function. No threshold T level was observed for any outcome, and none of the 27 baseline characteristics predicted responsiveness to T., Conclusions: In older men with low libido and low T levels, improvements in sexual desire and activity in response to T treatment were related to the magnitude of increases in T and estradiol levels, but there was no clear evidence of a threshold effect.

Context: Concern exists that T replacement therapy (TRT) might increase the risk of prostate disease. There are limited data regarding the impact of TRT on prostate androgen concentrations., Objective: Determine the dose-dependent effects of exogenous T administration on intraprostatic androgen concentrations., Design: Twelve-week, double-blinded, randomized, placebo-controlled trial., Setting: Academic medical center., Participants: Sixty-two healthy eugonadal men, aged 25-55 years., Interventions: Subjects were randomly assigned to receive injections of acyline, a GnRH antagonist (used to achieve medical castration), every 2 weeks plus transdermal T gel (1.25 g, 2.5 g, 5.0 g, 10 g, or 15 g daily), or placebo injections and transdermal gel for 12 weeks., Main Outcomes: Serum T and dihydrotestosterone (DHT) were measured at baseline and every 2 weeks during treatment. Intraprostatic T and DHT concentrations were assessed from tissue obtained through ultrasound-guided prostate needle biopsies at week 12. Androgens were quantified by liquid chromatography-tandem mass spectrometry., Results: 51 men completed the study and were included in the analysis. There were no significant adverse events. Exogenous T resulted in a dose-dependent increase in serum T and DHT concentrations (190-770 and 60-180 ng/dL, respectively). Although intraprostatic T differed among dose groups (P = .01), intraprostatic DHT was comparable regardless of T dose (P = .11) and was 10- to 20-fold greater than intraprostatic T., Conclusions: In healthy, medically castrate men receiving exogenous T, the total intraprostatic androgen concentration (predominantly DHT) remained stable across serum T concentrations within the physiological range. These findings further our knowledge of the relationship between serum and intraprostatic androgens and suggest that physiological serum T achieved by TRT is unlikely to alter the prostate hormonal milieu.

Background: Serum testosterone concentrations decrease as men age, but benefits of raising testosterone levels in older men have not been established., Methods: We assigned 790 men 65 years of age or older with a serum testosterone concentration of less than 275 ng per deciliter and symptoms suggesting hypoandrogenism to receive either testosterone gel or placebo gel for 1 year. Each man participated in one or more of three trials--the Sexual Function Trial, the Physical Function Trial, and the Vitality Trial. The primary outcome of each of the individual trials was also evaluated in all participants., Results: Testosterone treatment increased serum testosterone levels to the mid-normal range for men 19 to 40 years of age. The increase in testosterone levels was associated with significantly increased sexual activity, as assessed by the Psychosexual Daily Questionnaire (P<0.001), as well as significantly increased sexual desire and erectile function. The percentage of men who had an increase of at least 50 m in the 6-minute walking distance did not differ significantly between the two study groups in the Physical Function Trial but did differ significantly when men in all three trials were included (20.5% of men who received testosterone vs. 12.6% of men who received placebo, P=0.003). Testosterone had no significant benefit with respect to vitality, as assessed by the Functional Assessment of Chronic Illness Therapy-Fatigue scale, but men who received testosterone reported slightly better mood and lower severity of depressive symptoms than those who received placebo. The rates of adverse events were similar in the two groups., Conclusions: In symptomatic men 65 years of age or older, raising testosterone concentrations for 1 year from moderately low to the mid-normal range for men 19 to 40 years of age had a moderate benefit with respect to sexual function and some benefit with respect to mood and depressive symptoms but no benefit with respect to vitality or walking distance. The number of participants was too few to draw conclusions about the risks of testosterone treatment. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00799617.).

Measurement of intratesticular sex steroid concentrations in men informs both the development of male hormonal contraceptives and the understanding of male infertility. Given the challenges of using invasive techniques to measure testicular hormone physiology, our group has used a minimally-invasive fine-needle aspiration technique to measure intratesticular hormones in normal healthy men. Herein, we present a post-hoc analysis of the safety and efficacy of testicular fine-needle aspiration (FNA) completed as part of six clinical trials. From 2001 through 2011, a total of 404 procedures were conducted among 163 research volunteers, 85.9% of which were successful in obtaining sufficient fluid for the measurement of intratesticular steroid concentrations. Pain was the most common side effect, with 36.8% of procedures associated with moderate procedural pain and 4.7% with severe procedural pain. Postprocedural pain was uncommon and abated within a few days. Mild local bruising occurred with 14.9% of procedures. Two serious adverse events (0.5%) required surgical intervention. The risk of an adverse event was not associated with age, body mass index, testicular size, or the volume of fluid aspirated. Testicular FNA to obtain fluid for measurement of intratesticular steroid concentrations frequently causes mild to moderate procedural pain, but serious adverse events occur rarely. Testicular FNA has been instrumental for defining human intratesticular hormone physiology and is a minimally-invasive, safe, effective method for obtaining fluid for research on testicular physiology and pathology.

Objective: Total testosterone concentrations are influenced by sex hormone-binding globulin (SHBG) concentrations, which are decreased by obesity and increased with ageing. Therefore, we sought to understand and compare the associations of ageing and obesity with SHBG., Design: We performed a retrospective, cross-sectional analysis of the associations of obesity and age on SHBG and testosterone measurements in men being evaluated for hypogonadism., Patients, Measurements and Analysis: A total of 3671 men who underwent laboratory testing for testosterone deficiency from the Veterans Administration Puget Sound Health Care System from 1997 through 2007 was included. Univariate and multivariate linear regression modelling of the associations between age and body mass index (BMI) and SHBG was performed., Results: Obesity was associated with a significantly lower SHBG [β = -1·26 (95% CI -1·14, -1·38) nmol/l] per unit increase in BMI. In contrast, ageing was associated with a significantly increased SHBG [β = 0·46 (95% CI 0·39, 0·53) nmol/l per year] (P < 0·001 for both effects). The association of obesity with lower SHBG was two to three times larger than the association of ageing with increased SHBG in both univariate and multivariate modelling. On average, obese men (BMI >30 kg/m(2)) had significantly lower SHBG and total testosterone concentrations than nonobese men [(mean ± SD) SHBG: 36 ± 22 vs 50 ± 27 nmol/l and total testosterone: 10·5 ± 5·4 nmol/l vs 14·1 ± 7·4 nmol/l; (P < 0·001 for both comparisons)], but calculated free testosterone concentrations did not differ between obese and nonobese men., Conclusions: We found that the association between obesity and lowered SHBG is greater than the association of ageing with increased SHBG. These competing effects may impact total testosterone measurements for the diagnosis of low testosterone, particularly in obese men., (© 2015 John Wiley & Sons Ltd.)

Background: We describe the recruitment of men for The Testosterone (T) Trials, which were designed to determine the efficacy of T treatment., Methods: Men were eligible if they were ≥65 years, had an average of two morning total T values <275 ng/dL with neither value >300 ng/mL, and had symptoms and objective evidence of mobility limitation, sexual dysfunction, and/or low vitality. Men had to be eligible for and enroll in at least one of these three main trials (physical function, sexual function, vitality)., Results: Men were recruited primarily through mass mailings in 12 U.S. communities: 82% of men who contacted the sites did so in response to mailings. Men who responded were screened by telephone to ascertain eligibility. Of 51,085 telephone screens, 53.5% were eligible for further screening. Of 23,889 initial screening visits (SV1), 2,781 (11.6%) men were eligible for the second screening visit (SV2), which 2,261 (81.3%) completed. At SV2, 931 (41.2%) men met the criteria for one or more trials, the T level criterion and had no other exclusions. Of these, 790 (84.6%) were randomized; 99 (12.5%) in all three trials and 348 (44%) in two trials. Their mean age was 72 years and mean body mass index (BMI) was 31.0 kg/m(2). Mean (standard deviation) total T (ng/dL) was 212.0 (40.0)., Conclusion: Despite the telephone screening to enrollment ratio of 65 to 1, we met the recruitment goals for each trial. Recruitment of symptomatic older men with low testosterone levels is difficult but feasible., (© The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Clinical practice guidelines recommend that testosterone (T) levels be measured on ≥2 occasions to confirm a diagnosis of hypogonadism, gonadotropins be measured to determine whether hypogonadism is primary or secondary, and T levels be measured to monitor the adequacy of T therapy. However, it is not known whether hormone testing as recommended by guidelines is routinely performed in real-world clinical practice., Aim: The aim of this study was to assess the use of hormone testing for the diagnosis and evaluation of hypogonadism and monitoring of T therapy in clinical practice., Methods: In this retrospective cohort study of the Truven Health Marketscan(®) Commercial and Medicare Supplemental Insurance Databases during 2010-2012, 63,534 men over 18 years old who received T therapy and had continuous medical benefit enrollment for 1 year prior to and 6 months after T therapy initiation were included in this analysis., Main Outcome Measures: Proportion of patients who received ≥2, 1, or no T-level determinations prior to or following T therapy initiation., Results: Seventy-one percent of hypogonadal men had T measured at least once and 40% had ≥ 2 tests, but only 12% of men had luteinizing hormone and/or follicle-stimulating hormone levels measured prior to T therapy initiation. Following T therapy initiation, 46% had ≥1 follow-up T measurements., Conclusions: Appropriate use of T and gonadotropin levels in clinical practice as recommended by guidelines is suboptimal, increasing the possibility of overdiagnosis of male hypogonadism, underdiagnosis of secondary hypogonadism, and inappropriate T therapy use and management. Further investigation is needed into reasons for nonadherence to guidelines for appropriate hormone testing to inform future quality improvement efforts., (© 2015 International Society for Sexual Medicine.)

Context: The optimal frequency for on-treatment serum T measurement used for dose adjustment after transdermal T gel application is unknown, especially in older men with thinner skin and slower metabolic clearance., Objectives: The objectives of the study was to determine the variability of postgel application serum T concentrations and assess whether single levels are reflective of average serum T concentrations over 24 hours (Cavg0-24)., Design: This was a double-blinded, placebo-controlled randomized trial., Setting: The study was conducted at five academic centers., Participants: Forty-seven symptomatic men 65 years old or older with an average of two morning T concentration less than 275 ng/dL participated in the study., Intervention(s): Transdermal T or placebo gel was applied for 120 ± 14 days. Monthly dose adjustments were made if necessary to target serum T between 400 and 500 to 800 ng/dL., Main Outcome Measures: Variability of serum T 2 hours after the gel application on two outpatient visits and at multiple time points over 24 hours during the inpatient day was measured., Results: On-treatment T levels varied substantially on the 2 ambulatory days and over 24 hours during the inpatient day. Ambulatory 2-hour postapplication T levels did not correlate significantly with either 2-hour postapplication serum T or Cavg0-24 measured during the inpatient day. Only 22.2% of men receiving T had a Cavg0-24 within the target range of 500-800 ng/dL; 81.5% had a Cavg0-24 within the broader 300-1000 ng/dL range., Conclusion: Large within-individual variations in serum T after T gel application render ambulatory 2-hour postapplication T level a poor indicator of average serum T on another day. Our data point out the limitations of dose adjustments based on a single postapplication serum T measurement.

Introduction: This study investigated the effects of testosterone (T) treatment on cognition, mood, and quality of life in men with mild cognitive impairment (MCI) and low serum T levels., Methods: A total of 351 community-dwelling men were screened, and 37 men evidenced both MCI and low T of whom 27 agreed for further screening. Twenty-two met all the study inclusion/exclusion criteria and enrolled in a 6-month randomized, double-blind, placebo-controlled study., Results: Total T levels significantly increased in the T treatment group. No significant changes were observed in measures of cognition, mood, or quality of life other than improvement in 1 objective measure of verbal memory (P < .05) and decreased depression symptoms (P < .02) in the treatment group., Conclusions: Testosterone treatment may modestly improve verbal memory and depression symptoms in men with both MCI and low T., (© The Author(s) 2014.)

Purpose: Optimizing androgen suppression may provide better control of localized prostate cancer (PCa). Numerous trials have supported the benefit of combining androgen deprivation therapy with definitive radiation therapy in men with locally advanced or high-grade disease. Addition of abiraterone to luteinizing hormone-releasing hormone agonist (LHRHa) with radiation has not been reported. We examined the safety of this combination as well as its impact on androgen suppression., Methods and Materials: A prospective, phase 2 study was conducted in men with localized PCa treated with 6 months of neoadjuvant and concurrent abiraterone with LHRHa and radiation. Duration of adjuvant LHRHa was at the discretion of the treating clinician. Prostate biopsy assays were obtained prior to the start of therapy and prior to radiation. Sera and tissue androgen levels were measured by liquid chromatography-tandem mass spectrometry., Results: A total of 22 men with intermediate- (n=3) and high-risk PCa (n=19) received study therapy. Sixteen men completed the intended course of abiraterone, and 19 men completed planned radiation to 77.4 to 81 Gy. Radiation to pelvic nodes was administered in 20 men. The following grade 3 toxicities were reported: lymphopenia (14 patients), fatigue (1 patient), transaminitis (2 patients), hypertension (2 patients), and hypokalemia (1 patient). There were no grade 4 toxicities. All 21 men who complied with at least 3 months of abiraterone therapy had a preradiation prostate-specific antigen (PSA) concentration nadir of <0.3 ng/mL. Median levels of tissue androgen downstream of CYP17A were significantly suppressed after treatment with abiraterone, and upstream steroids were increased. At median follow-up of 21 months (range: 3-37 months), only 1 patient (who had discontinued abiraterone at 3 months) had biochemical relapse., Conclusions: Addition of abiraterone to LHRHa with radiation is safe and achieves effective prostatic androgen suppression. Preliminary analysis of the clinical data is also promising, with excellent PSA nadir and no relapse to date in this high-risk population., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Context: The prevalence of sexual dysfunction, low vitality, and poor physical function increases with aging, as does the prevalence of low total and free testosterone (TT and FT) levels. However, the relationship between sex hormones and age-related alterations in older men is not clear., Objective: To test the hypotheses that baseline serum TT, FT, estradiol (E2), and sex hormone-binding globulin (SHBG) levels are independently associated with sexual function, vitality, and physical function in older symptomatic men with low testosterone levels participating in the Testosterone Trials (TTrials)., Design: Cross-sectional study of baseline measures in the TTrials., Setting: The study was conducted at 12 sites in the United States., Participants: The 788 TTrials participants were ≥ 65 years and had evidence of sexual dysfunction, diminished vitality, and/or mobility disability, and an average of two TT < 275 ng/dL., Interventions: None., Main Outcome Measures: Question 4 of Psychosocial Daily Questionnaire (PDQ-Q4), the FACIT-Fatigue Scale, and the 6-minute walk test., Results: Baseline serum TT and FT, but not E2 or SHBG levels had small, but statistically significant associations with validated measures of sexual desire, erectile function, and sexual activity. None of these hormones was significantly associated within or across trials with FACIT-Fatigue, PHQ-9 Depression or Physical Function-10 scores, or gait speed., Conclusions: FT and TT levels were consistently, independently, and positively associated, albeit to a small degree, with measures of sexual desire, erectile function, and sexual activity, but not with measures of vitality or physical function in symptomatic older men with low T who qualified for the TTrials.

Low serum testosterone (T) is common and increasingly prevalent with increased age. Recent studies report an 'epidemic' of T prescribing and concern about unnecessary T treatment. We investigated the number of men tested for T, the prevalence of low serum T levels, and initiation of T treatment among those with low T levels in men treated at Veterans Affairs (VA) facilities in the Northwest US (VISN 20). We identified male Veterans aged 40-89 years and examined yearly proportions of men tested for T, found to have low T levels (total T < 280 ng/dL, free T < 34 pg/mL, or bioavailable T < 84 ng/dL), and subsequently treated with T from 2002 to 2011. We excluded men who had T treatment in the year prior and men with diagnoses of prostate or breast cancer. Treatment initiation was defined as the first prescription for T within a year following a low T test. From 2002 to 2011, the yearly population of eligible men in VISN 20 increased from 129 247 to 163 572. The proportion of men who had serum T tests increased from 3.2% in 2002 to 5.8% in 2011. Among the tested men, the percentage of men with low T levels increased from 35.0 to 47.3%. However, the proportion of men with low T levels who were given T treatment within a year decreased from 31.0 to 28.0%. Despite large increases in T testing, and detection of men with low T levels, there was a slight decrease in the proportion of men with low T levels who were treated with T. The decrease in T treatment during this time period contrasts with other studies and may be related to higher comorbidity in Veterans and/or VA formulary restrictions on the use of transdermal T formulations., (© 2015 American Society of Andrology and European Academy of Andrology.)

Purpose: Cure rates for localized high-risk prostate cancers (PCa) and some intermediate-risk PCa are frequently suboptimal with local therapy. Outcomes are improved by concomitant androgen-deprivation therapy (ADT) with radiation therapy, but not by concomitant ADT with surgery. Luteinizing hormone-releasing hormone agonist (LHRHa; leuprolide acetate) does not reduce serum androgens as effectively as abiraterone acetate (AA), a prodrug of abiraterone, a CYP17 inhibitor that lowers serum testosterone (< 1 ng/dL) and improves survival in metastatic PCa. The possibility that greater androgen suppression in patients with localized high-risk PCa will result in improved clinical outcomes makes paramount the reassessment of neoadjuvant ADT with more robust androgen suppression., Patients and Methods: A neoadjuvant randomized phase II trial of LHRHa with AA was conducted in patients with localized high-risk PCa (N = 58). For the first 12 weeks, patients were randomly assigned to LHRHa versus LHRHa plus AA. After a research prostate biopsy, all patients received 12 additional weeks of LHRHa plus AA followed by prostatectomy., Results: The levels of intraprostatic androgens from 12-week prostate biopsies, including the primary end point (dihydrotestosterone/testosterone), were significantly lower (dehydroepiandrosterone, Δ(4)-androstene-3,17-dione, dihydrotestosterone, all P < .001; testosterone, P < .05) with LHRHa plus AA compared with LHRHa alone. Prostatectomy pathologic staging demonstrated a low incidence of complete responses and minimal residual disease, with residual T3- or lymph node-positive disease in the majority., Conclusion: LHRHa plus AA treatment suppresses tissue androgens more effectively than LHRHa alone. Intensive intratumoral androgen suppression with LHRHa plus AA before prostatectomy for localized high-risk PCa may reduce tumor burden., (© 2014 by American Society of Clinical Oncology.)

Objective: Ischaemic stroke is a major cause of morbidity and mortality in elderly men. Our main objective was to examine whether testosterone (T) or dihydrotestosterone (DHT) was associated with incident ischaemic stroke in elderly men., Design: Cohort study., Participants: Elderly men in the Cardiovascular Health Study who had no history of stroke, heart disease or prostate cancer as of 1994 and were followed until December 2010., Measurements: Adjudicated ischaemic stroke., Results: Among 1032 men (mean age 76, range 66-97), followed for a median of 10 years, 114 had an incident ischaemic stroke. Total T and free T were not significantly associated with stroke risk, while DHT had a nonlinear association with incident stroke (P = 0·006) in analyses adjusted for stroke risk factors. The lowest risk of stroke was at DHT levels of 50-75 ng/dl, with greater risk of stroke at DHT levels above 75 ng/dl or below 50 ng/dl. Results were unchanged when SHBG was added to the model. Calculated free DHT had an inverse linear association with incident ischaemic stroke with HR 0·77 (95% CI, 0·61, 0·98) per standard deviation in analyses adjusted for stroke risk factors., Conclusions: Dihydrotestosterone had a nonlinear association with stroke risk in which there was an optimal DHT level associated with the lowest stroke risk. Further studies are needed to confirm these results and to clarify whether there is an optimal androgen range associated with the least risk of adverse outcomes in elderly men., (© 2014 John Wiley & Sons Ltd.)

Background: Factors influencing differential responses of prostate tumors to androgen receptor (AR) axis-directed therapeutics are poorly understood, and predictors of treatment efficacy are needed. We hypothesized that the efficacy of inhibiting DHT ligand synthesis would associate with intra-tumoral androgen ratios indicative of relative dependence on DHT-mediated growth., Methods: We characterized two androgen-sensitive prostate cancer xenograft models after androgen suppression by castration in combination with the SRD5A inhibitor, dutasteride, as well as a panel of castration resistant metastases obtained via rapid autopsy., Results: In LuCaP35 tumors (intra-tumoral T:DHT ratio 2:1) dutasteride suppressed DHT to 0.02 ng/gm and prolonged survival vs. castration alone (337 vs.152 days, HR 2.8, p = 0.0015). In LuCaP96 tumors (T:DHT 10:1), survival was not improved despite similar DHT reduction (0.02 ng/gm). LuCaP35 demonstrated higher expression of steroid biosynthetic enzymes maintaining DHT levels (5-fold higher SRD5A1, 41 fold higher, 99-fold higher RL-HSD, p<0.0001 for both), reconstitution of intra-tumoral DHT (to ∼30% of untreated tumors), and ∼2 fold increased expression of full length AR. In contrast, LuCaP96 demonstrated higher levels of steroid catabolizing enzymes (6.9-fold higher AKR1C2, 3000-fold higher UGT2B15, p = 0.002 and p<0.0001 respectively), persistent suppression of intra-tumoral DHT, and 6-8 fold induction of full length AR and the ligand independent V7 AR splice variant. Human metastases demonstrated bio-active androgen levels and AR full length and AR splice-variant expression consistent with the range observed in xenografts., Conclusions: Intrinsic differences in basal steroidogenesis, as well as variable expression of full length and splice-variant AR, associate with response and resistance to pre-receptor AR ligand suppression. Expression of steroidogenic enzymes and AR isoforms may serve as potential biomarkers of sensitivity to potent AR-axis inhibition and should be validated in additional models.

Purpose of Review: The purpose of this study is to review recent studies that examined the association of endogenous and exogenous testosterone and mortality in older men., Recent Findings: Over the past several years, there has been a steep rise in testosterone prescriptions. The increased use of testosterone occurred in the context of several studies that reported an association between low serum testosterone and increased cardiovascular events and mortality. In contrast, recent studies have reported an association between testosterone treatment and adverse events. A testosterone treatment trial of mobility-impaired elderly men with prevalent cardiovascular disease was stopped due to increased cardiovascular events in the T-treated men and a meta-analysis reported increased cardiovascular events in T-treated men. In two recent large observational studies, testosterone treatment was associated with an increased risk for serious adverse cardiovascular events., Summary: Low testosterone is associated with mortality in multiple cohort studies; however, it is unclear if this is a causal association or due to low testosterone being a biomarker of poor health. Given recent reports of adverse outcomes associated with testosterone treatment, a conservative use of testosterone is warranted in men with cardiovascular disease who may be at greater risk for adverse outcomes.

Testosterone remains a key target in the treatment of advanced prostate cancer. The relationship of free testosterone to prostate cancer treatment and outcomes remains largely unexplored. A consensus of prostate cancer experts was convened in 2013 to review current knowledge surrounding relationship of total and free testosterone to prostate cancer, discuss the free hormone hypothesis, and highlight future avenues for therapeutics. Free testosterone may better reflect prostate cancer tissue androgen levels than serum total testosterone concentration. Free testosterone deserves more research regarding its relation to clinical outcomes., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background The prevalence of low testosterone levels in men increases with age, as does the prevalence of decreased mobility, sexual function, self-perceived vitality, cognitive abilities, bone mineral density, and glucose tolerance, and of increased anemia and coronary artery disease. Similar changes occur in men who have low serum testosterone concentrations due to known pituitary or testicular disease, and testosterone treatment improves the abnormalities. Prior studies of the effect of testosterone treatment in elderly men, however, have produced equivocal results. Purpose To describe a coordinated set of clinical trials designed to avoid the pitfalls of prior studies and to determine definitively whether testosterone treatment of elderly men with low testosterone is efficacious in improving symptoms and objective measures of age-associated conditions. Methods We present the scientific and clinical rationale for the decisions made in the design of this set of trials. Results We designed The Testosterone Trials as a coordinated set of seven trials to determine if testosterone treatment of elderly men with low serum testosterone concentrations and symptoms and objective evidence of impaired mobility and/or diminished libido and/or reduced vitality would be efficacious in improving mobility (Physical Function Trial), sexual function (Sexual Function Trial), fatigue (Vitality Trial), cognitive function (Cognitive Function Trial), hemoglobin (Anemia Trial), bone density (Bone Trial), and coronary artery plaque volume (Cardiovascular Trial). The scientific advantages of this coordination were common eligibility criteria, common approaches to treatment and monitoring, and the ability to pool safety data. The logistical advantages were a single steering committee, data coordinating center and data and safety monitoring board, the same clinical trial sites, and the possibility of men participating in multiple trials. The major consideration in participant selection was setting the eligibility criterion for serum testosterone low enough to ensure that the men were unequivocally testosterone deficient, but not so low as to preclude sufficient enrollment or eventual generalizability of the results. The major considerations in choosing primary outcomes for each trial were identifying those of the highest clinical importance and identifying the minimum clinically important differences between treatment arms for sample size estimation. Potential limitations Setting the serum testosterone concentration sufficiently low to ensure that most men would be unequivocally testosterone deficient, as well as many other entry criteria, resulted in screening approximately 30 men in person to randomize one participant. Conclusion Designing The Testosterone Trials as a coordinated set of seven trials afforded many important scientific and logistical advantages but required an intensive recruitment and screening effort.

Context: Low testosterone (T) is associated with prevalent cardiovascular disease (CVD) and mortality. DHT, a more potent androgen, may also be associated with CVD and mortality, but few studies have examined this., Objective: The study objective was to examine whether T and DHT are risk factors for incident CVD and mortality., Design: In a longitudinal cohort study, we evaluated whether total T, calculated free T (cFT), DHT, and calculated free DHT were associated with incident CVD and mortality in men in the Cardiovascular Health Study (mean age 76, range 66-97 years) who were free of CVD at the time of blood collection., Main Outcome: The main outcomes were incident CVD and all-cause mortality., Results: Among 1032 men followed for a median of 9 years, 436 incident CVD events and 777 deaths occurred. In models adjusted for cardiovascular risk factors, total T and cFT were not associated with incident CVD or all-cause mortality, whereas DHT and calculated free DHT had curvilinear associations with incident CVD (P < .002 and P = .04, respectively) and all-cause mortality (P < .001 for both)., Conclusions: In a cohort of elderly men, DHT and calculated free DHT were associated with incident CVD and all-cause mortality. Further studies are needed to confirm these results and to clarify the underlying physiologic mechanisms.

Purpose: Ligand-mediated activation of the androgen receptor (AR) is critical for prostate cancer (PCa) survival and proliferation. The failure to completely ablate tissue androgens may limit suppression of PCa growth. We evaluated combinations of CYP17A and 5-α-reductase inhibitors for reducing prostate androgen levels, AR signaling, and PCa volumes., Patients and Methods: Thirty-five men with intermediate/high-risk clinically localized PCa were randomly assigned to goserelin combined with dutasteride (ZD), bicalutamide and dutasteride (ZBD), or bicalutamide, dutasteride, and ketoconazole (ZBDK) for 3 months before prostatectomy. Controls included patients receiving combined androgen blockade with luteinizing hormone-releasing hormone agonist and bicalutamide. The primary outcome measure was tissue dihydrotestosterone (DHT) concentration., Results: Prostate DHT levels were substantially lower in all experimental arms (0.02 to 0.04 ng/g v 0.92 ng/g in controls; P < .001). The ZBDK group demonstrated the greatest percentage decline in serum testosterone, androsterone, and dehydroepiandrosterone sulfate (P < .05 for all). Staining for AR and the androgen-regulated genes prostate-specific antigen and TMPRSS2 was strongly suppressed in benign glands and moderately in malignant glands (P < .05 for all). Two patients had pathologic complete response, and nine had ≤ 0.2 cm(3) of residual tumor (defined as a near-complete response), with the largest numbers of complete and near-complete responses in the ZBDK group., Conclusion: Addition of androgen synthesis inhibitors lowers prostate androgens below that achieved with standard therapy, but significant AR signaling remains. Tissue-based analysis of steroids and AR signaling is critical to informing the search for optimal local and systemic control of high-risk prostate cancer.

The only indication for testosterone administration in older men is testosterone replacement therapy for male hypogonadism. Compared with young hypogonadal men, the diagnosis and management of male hypogonadism in older men is more challenging. Both the clinical manifestations of androgen deficiency and low testosterone levels may be caused or modified by comorbid illnesses that occur and medications taken more frequently by older men, resulting in a greater likelihood for overdiagnosis of hypogonadism and subsequent inappropriate use of and inadequate response to testosterone treatment. It is important to use a systematic, holistic approach to the diagnosis and management of older men with hypogonadism., (Published by Elsevier Inc.)

Context: The concentration of intratesticular testosterone (IT-T) required for human spermatogenesis is unknown because spermatogenesis can persist despite the markedly reduced IT-T concentrations observed with LH suppression. Methods to lower IT-T further are needed to determine the relationship between IT-T and spermatogenesis., Objective: The objective of the study was to determine the effect of inhibiting the synthesis and metabolism of testosterone (T) on IT-T in gonadotropin-suppressed human testes., Design/setting/patients: Forty normal men participated in a blinded, placebo-controlled, randomized trial at an academic center. INTERVENTION/OUTCOME MEASURES: All men were first administered the GnRH antagonist acyline to suppress LH. Forty-eight hours after acyline administration, subjects were randomly assigned to placebo, ketoconazole (to inhibit T synthesis) at 400 or 800 mg, dutasteride (to inhibit T metabolism) 2.5 mg, or anastrazole (to inhibit T metabolism) 1 mg, daily for 7 days (n = 8/group). Intratesticular steroid concentrations were measured 48 hours after acyline administration alone and again after 7 days of combination treatment., Results: After 7 days of combination treatment, the median IT-T (25th, 75th percentile) in the placebo group was 14 (8.0, 21.2) ng/mL. IT-T was reduced to 3.7 (2.5, 7.1) ng/mL in the ketoconazole 400 mg group and 1.7 (0.8, 4.0) ng/mL in the ketoconazole 800 mg group (P < .001 vs placebo for both comparisons). IT-T concentrations in the dutasteride and anastrazole groups were similar to placebo., Conclusion: Combining inhibition of steroidogenesis with gonadotropin suppression lowers IT-T more than gonadotropin suppression alone. This combination might be useful to determine the minimum IT-T concentration necessary for human spermatogenesis, information essential for developing male hormonal contraceptives.

Objective: To study the potential role for using serum biomarkers, including insulin-like factor 3 (INSL3), 17α-hydroxyprogesterone, antimüllerian hormone, and inhibin B, as correlates of intratesticular T (IT-T) concentrations in men., Design: Prospective, randomized, controlled trial., Setting: University-based medical center., Patient(s): Thirty-seven healthy men aged 18-50 years., Intervention(s): All men received the GnRH antagonist acyline, plus very low doses of hCG (0 IU, 15 IU, 60 IU, or 125 IU) SC every other day or 7.5 g T gel daily (75 mg delivered). The IT-T concentrations obtained by percutaneous testicular aspiration with simultaneous serum protein and steroid concentrations were measured at baseline and after 10 days of treatment., Main Outcome Measure(s): Intratesticular and serum hormone and gonadotropin concentrations., Result(s): After 10 days of gonadotropin suppression, serum INSL3 decreased by more than 90% and correlated highly with IT-T concentrations. In contrast, serum inhibin B, antimüllerian hormone, and 17α-hydroxyprogesterone did not correlate with IT-T. Serum INSL3 increased with the dose of hCG administered and returned to baseline after treatment., Conclusion(s): Serum INSL3 correlates highly with IT-T and serum T concentrations during acute gonadotropin suppression in men. Human chorionic gonadotropin stimulates dose-dependent increases in INSL3 and IT-T in healthy men and might be a useful biomarker of IT-T concentration in some clinical settings., Clinical Trial Registration Number: NCT# 00839319., (Copyright © 2013 American Society for Reproductive Medicine. All rights reserved.)

Context: Male hormonal contraception (MHC) combines hypothalamic-pituitary-gonadal axis blockade with exogenous androgen delivery to maintain extragonadal androgen end-organ effects. Concern exists that MHC may adversely impact prostate health., Objective: The objective of the study was to determine the molecular impact of MHC on intraprostatic androgen concentrations and androgen action., Design: This was a single-blind, randomized, placebo-controlled study., Setting: The study was conducted at an academic medical center., Participants: 32 healthy men aged 25-55 yr participated in the study., Intervention: Interventions included placebo, daily transdermal testosterone (T) (T-gel), T-gel + depomedroxyprogesterone acetate (T+DMPA), or T-gel + dutasteride daily (T+D) for 12 wk, and prostate biopsy during treatment wk 10., Main Outcome Measures: Serum and prostate androgen concentrations and prostate epithelial-cell gene expression were measured., Results: Thirty men completed the study. Serum T levels were significantly increased in T-gel and T+D groups compared with baseline (P < 0.05) but were decreased with the addition of DMPA. Intraprostatic androgens were no different from placebo with T-gel treatment. Addition of DMPA to T resulted in 40% lower intraprostatic dihydrotestosterone (DHT) concentration (P = 0.0273 vs. placebo), whereas combining dutasteride with T resulted in a 90% decrease in intraprostatic DHT (P = 0.0012), 11-fold increased intraprostatic T (P = 0.0011), and 7-fold increased intraprostatic androstenedione (P = 0.0011). Significant differences in global or androgen-regulated prostate epithelial-cell gene expression were not observed. Androgen-regulated gene expression correlated with epithelial-cell androgen receptor and prostatic DHT in placebo, T-gel, and T+DMPA arms and with T and androstenedione levels in the T+D arm., Conclusions: MHC regimens do not markedly alter gene expression in benign prostate epithelium, suggesting they may not alter risk of prostate disease. Longer-term studies examining the impact of MHC on prostate health are needed.

The effects of androgens on cardiovascular disease (CVD) risk in men remain unclear. To better characterize the relationship between androgens and HDL, we investigated the effects of testosterone replacement on HDL protein composition and serum HDL-mediated cholesterol efflux in hypogonadal men. Twenty-three older hypogonadal men (ages 51-83, baseline testosterone < 280 ng/dl) were administered replacement testosterone therapy (1% transdermal gel) with or without the 5α-reductase inhibitor dutasteride. At baseline and after three months of treatment, we determined fasting lipid concentrations, HDL protein composition, and the cholesterol efflux capacity of serum HDL. Testosterone replacement did not affect HDL cholesterol (HDL-C) concentrations but conferred significant increases in HDL-associated paraoxonase 1 (PON1) and fibrinogen α chain (FGA) (P = 0.022 and P = 0.023, respectively) and a decrease in apolipoprotein A-IV (apoA-IV) (P = 0.016). Exogenous testosterone did not affect the cholesterol efflux capacity of serum HDL. No differences were observed between men who received testosterone alone and those who also received dutasteride. Testosterone replacement in older hypogonadal men alters the protein composition of HDL but does not significantly change serum HDL-mediated cholesterol efflux. These effects appear independent of testosterone conversion to dihydrotestosterone. Further research is needed to determine how changes in HDL protein content affect CVD risk in men.

Context: Low testosterone levels in men have been associated with increased mortality. However, the influence of testosterone treatment on mortality in men with low testosterone levels is not known., Objective: The objective of the study was to examine the association between testosterone treatment and mortality in men with low testosterone levels., Design: This was an observational study of mortality in testosterone-treated compared with untreated men, assessed with time-varying, adjusted Cox proportional hazards regression models. Effect modification by age, diabetes, and coronary heart disease was tested a priori., Setting: The study was conducted with a clinical database that included seven Northwest Veterans Affairs medical centers., Patients: Patients included a cohort of 1031 male veterans, aged older than 40 yr, with low total testosterone [≤250 ng/dl (8.7 nmol/liter)] and no history of prostate cancer, assessed between January 2001 and December 2002 and followed up through the end of 2005., Main Outcome Measure: Total mortality in testosterone-treated compared with untreated men was measured., Results: Testosterone treatment was initiated in 398 men (39%) during routine clinical care. The mortality in testosterone-treated men was 10.3% compared with 20.7% in untreated men (P<0.0001) with a mortality rate of 3.4 deaths per 100 person-years for testosterone-treated men and 5.7 deaths per 100 person-years in men not treated with testosterone. After multivariable adjustment including age, body mass index, testosterone level, medical morbidity, diabetes, and coronary heart disease, testosterone treatment was associated with decreased risk of death (hazard ratio 0.61; 95% confidence interval 0.42-0.88; P = 0.008). No significant effect modification was found by age, diabetes, or coronary heart disease., Conclusions: In an observational cohort of men with low testosterone levels, testosterone treatment was associated with decreased mortality compared with no testosterone treatment. These results should be interpreted cautiously because residual confounding may still be a source of bias. Large, randomized clinical trials are needed to better characterize the health effects of testosterone treatment in older men with low testosterone levels.