madman
Super Moderator
ABSTRACT
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 aged ≥40 years and who 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 2.54kg (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 kg (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 increases the leg press strength in 91.23 N (95%CI, 0.23 to 182.22) (p= 0.05) and leg extension in 144.10N (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 an increase in muscle mass and strength in addition to physical performance.
1. INTRODUCTION
The aging process naturally causes changes in the skeletal muscle system. These changes are, to some extent, related to the levels of certain hormones. Systemic concentrations of anabolic hormones gradually decrease over time, which may be associated with the impairment of muscle strength and function (Guadalupe-Grau et al., 2017).
Among the hormones considered anabolic, testosterone (T), the main male sex hormone, has major metabolic and vascular actions, with multiple physiological effects in various tissues and organs, as well as an essential role in maintaining muscle mass and function (Saad et al., 2017; Harada, 2018Oki, et al., 2015). In muscle it is responsible for stimulating protein synthesis and inhibiting protein degradation, favoring muscle hypertrophy. The physiological effects of T are induced by its binding to the intracellular androgen receptor, which when moving to the nucleus induces the transcription of specific genes (Vingren et al., 2010).
In view of the complexity and the various implications of T, there is growing interest in investigating its clinical applications. T deficiency has already been proven to correlate with the onset of components of sarcopenia, a disease rooted in adverse muscle changes that accumulate throughout life. The presence of sarcopenia increases the risk of falls, fractures, and mobility disorders, and contributes to reductions in quality of life, loss of independence, and need for long-term medical care (Cruz-Jentoft et al., 2018). In elderly men, the T replacement has already been shown to be capable of helping to reverse the deleterious effects of sarcopenia on muscle mass and function (Vingren et al., 2010), promoting changes in body composition, especially in lean body mass (LBM) gain and neuromuscular adaptation, mitigating the disability which results from senescence (Saad et al., 2017; Storer et al., 2016; Neto et al., 2015; Hsu et al., 2014; De Spiegeleeret al., 2018). However, the effects of such treatment are not fully understood; its objectives, dosages, and duration vary widely (Tenover, 1992; Wittert et al., 2003; Bhasin et al., 2005; Skinner et al., 2018), which hinders comparisons and definitive conclusions (Neto et al., 2015).
5. CONCLUSIONS
The results of this systematic review and meta-analysis indicate that T supplementation is associated with increases in muscle mass, strength, and physical performance in middle-aged and older men. Our meta-analysis showed that compared with the placebo or control group T supplementation had a beneficial effect on LBM, HGS, and LS (LPS and LE). Future studies should focus on standardizing T supplementation protocols, particularly with regard to dosage.
HIGHLIGHTS
*Testosterone supplementation is associated with positive gains in lean body mass;
*Testosterone is also associated with gains in strength in men;
*Testosterone supplementation may be a strategy to prevent sarcopenia in men;
*Better standardization of the testosterone supplementation method is necessary.
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 aged ≥40 years and who 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 2.54kg (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 kg (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 increases the leg press strength in 91.23 N (95%CI, 0.23 to 182.22) (p= 0.05) and leg extension in 144.10N (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 an increase in muscle mass and strength in addition to physical performance.
1. INTRODUCTION
The aging process naturally causes changes in the skeletal muscle system. These changes are, to some extent, related to the levels of certain hormones. Systemic concentrations of anabolic hormones gradually decrease over time, which may be associated with the impairment of muscle strength and function (Guadalupe-Grau et al., 2017).
Among the hormones considered anabolic, testosterone (T), the main male sex hormone, has major metabolic and vascular actions, with multiple physiological effects in various tissues and organs, as well as an essential role in maintaining muscle mass and function (Saad et al., 2017; Harada, 2018Oki, et al., 2015). In muscle it is responsible for stimulating protein synthesis and inhibiting protein degradation, favoring muscle hypertrophy. The physiological effects of T are induced by its binding to the intracellular androgen receptor, which when moving to the nucleus induces the transcription of specific genes (Vingren et al., 2010).
In view of the complexity and the various implications of T, there is growing interest in investigating its clinical applications. T deficiency has already been proven to correlate with the onset of components of sarcopenia, a disease rooted in adverse muscle changes that accumulate throughout life. The presence of sarcopenia increases the risk of falls, fractures, and mobility disorders, and contributes to reductions in quality of life, loss of independence, and need for long-term medical care (Cruz-Jentoft et al., 2018). In elderly men, the T replacement has already been shown to be capable of helping to reverse the deleterious effects of sarcopenia on muscle mass and function (Vingren et al., 2010), promoting changes in body composition, especially in lean body mass (LBM) gain and neuromuscular adaptation, mitigating the disability which results from senescence (Saad et al., 2017; Storer et al., 2016; Neto et al., 2015; Hsu et al., 2014; De Spiegeleeret al., 2018). However, the effects of such treatment are not fully understood; its objectives, dosages, and duration vary widely (Tenover, 1992; Wittert et al., 2003; Bhasin et al., 2005; Skinner et al., 2018), which hinders comparisons and definitive conclusions (Neto et al., 2015).
5. CONCLUSIONS
The results of this systematic review and meta-analysis indicate that T supplementation is associated with increases in muscle mass, strength, and physical performance in middle-aged and older men. Our meta-analysis showed that compared with the placebo or control group T supplementation had a beneficial effect on LBM, HGS, and LS (LPS and LE). Future studies should focus on standardizing T supplementation protocols, particularly with regard to dosage.
HIGHLIGHTS
*Testosterone supplementation is associated with positive gains in lean body mass;
*Testosterone is also associated with gains in strength in men;
*Testosterone supplementation may be a strategy to prevent sarcopenia in men;
*Better standardization of the testosterone supplementation method is necessary.
