Men's Health Research

Zinc is a vital trace element for normal function of the living system. In male, zinc is involved in various biological processes, an important function of which is as a balancer of hormones such as testosterone. For this purpose, studies related to the influence of zinc on serum testosterone were selected and summarized, including the effect of dietary zinc deficiency and zinc supplementation on testosterone concentrations. After preliminary searching of papers on databases, 38 papers including 8 clinical and 30 animal studies were included in this review. We concluded that zinc deficiency reduces testosterone levels and zinc supplementation improves testosterone levels. Furthermore, the effect degree of zinc on serum testosterone may vary depending on basal zinc and testosterone levels, zinc dosage form, elementary zinc dose, and duration. In conclusion, serum zinc was positively correlated with total testosterone, and moderate supplementation plays an important role in improving androgen.

[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/cm [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).

The aim of this study was to conduct a systematic review of the literature of randomized controlled trials on the effect of testosterone (T) supplementation compared to the placebo group or lower dose on sarcopenic components (muscle mass, strength and physical performance) in middle-aged and elderly men. Major electronic databases were searched for articles published on or before December 2019. Studies including individuals with age ≥ 40 years and which described the effect of T supplementation on sarcopenic components were found eligible (11 studies). Outcomes were calculated as the difference in means between the experimental and control/placebo groups, and data were presented as effect size with 95% confidence limits (95%CI). The meta-analysis was performed using a random effects model. Regarding lean body mass (LBM), eight studies evaluated the effect of T supplementation on this outcome, of these, seven reported gains after the intervention period. Our meta-analysis showed a beneficial effect on LBM of 2.54 kg (95% CI, 1.27 to 3.80) (p < 0.001). In muscle strength (MS), seven included studies evaluated the handgrip strength (HGS) and just one reported gain after the intervention period, but the meta-analysis showed an increase for HGS of 1.58 kgf (95%CI, 0.17 to 3.0) (p = 0.03). The second outcome for MS was leg strength (LS), where nine studies were included and five demonstrated gains in this parameter after the intervention period. In the meta-analysis, two out of three tests showed an effect on LS: T supplementation increase the leg press strength in 91.23 N (95%CI, 0.23 to 182.22) (p = 0.05) and leg extension in 144.10 N (95%CI, 44.21 to 244.00) (p < 0.01). In physical performance, four studies evaluated this outcome, with three of them showing positive effects in this parameter. In the meta-analysis, only two studies that reported the same assessment test (Physical Performance Test) were included, but no effect of T supplementation on this parameter was found. It can be concluded that T supplementation influences sarcopenic components in middle-aged and older men, because is associated with increased in muscle mass and strength in addition to physical performance.

The aim of this systematic review and meta-analysis was to evaluate the effect of vitamin D supplementation on total testosterone (TT) and sex hormone-binding globulin (SHBG) in men. We searched PubMed, Scopus and Web of Science for randomized, controlled trials of vitamin D supplementation in men ≥18 years old up to September 2018, without language restrictions. Meta-analysis was based on a random effects model. The systematic review was registered as CRD42018094498. We identified 3,402 articles, of which eight studies with 10 effect sizes met the inclusion criteria. Vitamin D daily dose equivalents ranged from 600 to 4,000 per day to 60,000 IU per week; duration was 6 weeks to 36 months. In general, vitamin D supplementation had no significant effect on TT (MD = 0.20, 95% CI: -0.20, 0.60, p = 0.336) and SHBG (MD = 1.56, 95% CI: -0.85, 3.97, p = 0.204). Subgroup analysis conducted with duration of prescription, type (daily or weekly), dosing frequency and baseline vitamin D and TT concentration showed that vitamin D did not significantly affect TT. The present study did not find any evidence to support beneficial effect of vitamin D supplementation on TT and SHBG in men. Thus, further large-scale randomised controlled trials are required to evaluate the effects of vitamin D supplementation on androgen in men.

[BACKGROUND AND AIMS] Testosterone supplementation therapy (TST) is a longstanding treatment for hypogonadal men with type 2 diabetes mellitus (T2DM), even though the benefits of TST are variable among trials. This meta-analysis was done to determine the specific role of TST in hypogonadal men with T2DM. [METHODS] PubMed, Embase, and Google Scholar were queried to discover eligible randomized controlled trials (RCTs) and observational studies. To quantify the specific effects of TST, we estimated pooled mean differences (MDs) and relative risks with 95% confidence intervals (CIs). [RESULTS] Our meta-analysis included 1596 hypogonadal T2DM subjects from 12 randomized controlled trials and one observational study. TST can significantly enhance glycemic control compared to placebo by decreasing homeostatic model assessment of insulin resistance (WMD = -1.55 [-2.65, -0.45]; p = 0.26; I2 = 20.2%), fasting glucose (WMD = -0.35 [-0.79, 0.10]; p = 0.07; I2 = 69.7%), fasting insulin (WMD = -2.88 [-6.12, 0.36]; p = In addition, TST can decrease cholesterol (WMD = -0.28 [-0.47, -0.09] p = 0.0008; I2 = 91%) and triglyceride (WMD = -0.23 [-0.43, -0.03] p = 0.03; I2 = 79.2%). Furthermore, Testosterone therapy is related to a significant rise in total testosterone levels (WMD = 5.08 [2.90, 7.26] p = 0.0002; I2 = 92.9%). Pooling of free testosterone levels indicated a larger increase in the patients who got TST than placebo (WMD = 81.21 [23.87, 138.54] p = 0.07; I2 = 70%). [CONCLUSION] Our findings suggested that TST can enhance glycemic control and hormone levels and reduce total cholesterol, triglyceride, LDL cholesterol whereas increase HDL cholesterol in hypogonadal T2DM patients. Therefore, in these patients, we propose TST alongside anti-diabetic treatment.

[IMPORTANCE] Countering depressive disorders is a public health priority. Currently, antidepressants are the first-line treatment, although they show modest effects. In men, testosterone treatment is a controversial alternative or adjunct treatment option. [OBJECTIVES] To examine the association of testosterone treatment with alleviation of depressive symptoms in men and to clarify moderating effects of testosterone status, depression status, age, treatment duration, and dosage. [DATA SOURCES] English-language studies published in peer-reviewed journals identified from PubMed/Medline, Embase, Scopus, PsychINFO, and the Cochrane Controlled Trials Register from database inception to March 5, 2018, using the search terms testosterone, mood, administration, dosage, adverse effects, deficiency, standards, therapeutic use, therapy, treatment, and supplementation. [STUDY SELECTION] Randomized placebo-controlled clinical trials (RCTs) of testosterone treatment that together cover a broad age range and hypogonadal or eugonadal men reporting depressive symptoms on psychometrically validated depression scales. [DATA EXTRACTION AND SYNTHESIS] Of 7690 identified records, 469 were evaluated against full study inclusion criteria after removing duplicates, reviews, and studies that did not examine male patients or testosterone. Quality assessment and data extraction from the remaining 27 RCTs were performed. [MAIN OUTCOMES AND MEASURES] Primary outcomes were testosterone treatment effectiveness (standardized score difference after treatment), efficacy (proportion of patients who responded to testosterone treatment with a score reduction of 50% or greater), and acceptability (proportion of patients who withdrew for any reason). [RESULTS] Random-effects meta-analysis of 27 RCTs including 1890 men suggested that testosterone treatment is associated with a significant reduction in depressive symptoms compared with placebo (Hedges g, 0.21; 95% CI, 0.10-0.32), showing an efficacy of odds ratio (OR), 2.30 (95% CI, 1.30-4.06). There was no significant difference between acceptability of testosterone treatment and placebo (OR, 0.79; 95% CI, 0.61-1.01). Meta-regression models suggested significant interactions for testosterone treatment with dosage and symptom variability at baseline. In the most conservative bias scenario, testosterone treatment remained significant whenever dosages greater than 0.5 g/wk were administered and symptom variability was kept low. [CONCLUSIONS AND RELEVANCE] Testosterone treatment appears to be effective and efficacious in reducing depressive symptoms in men, particularly when higher-dosage regimens were applied in carefully selected samples. However, given the heterogeneity of the included RCTs, more preregistered trials are needed that explicitly examine depression as the primary end point and consider relevant moderators.