1.
Adverse cardiovascular events and mortality in men during testosterone treatment: an individual patient and aggregate data meta-analysis.
Hudson, J, Cruickshank, M, Quinton, R, Aucott, L, Aceves-Martins, M, Gillies, K, Bhasin, S, Snyder, PJ, Ellenberg, SS, Grossmann, M, et al
The lancet. Healthy longevity. 2022;3(6):e381-e393
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Hypogonadism is caused by testosterone deficiency and results in diminished sexual function, muscle wastage, weakness, osteoporosis, and reduced quality of life. Testosterone supplementation is used as a therapy for hypogonadism but there is some doubt on its safety, and it may come with serious side effects such as heart attacks. This systematic review and meta-analysis aimed to determine the effect of testosterone supplementation on heart health. The results showed that heart disease risk was unaffected by testosterone supplementation and there was a trend for fewer deaths following treatment. It was concluded that testosterone did not affect short-medium-term heart attack risk, however there was a lack of evidence in the long-term. This study could be used by healthcare professionals to understand that testosterone supplementation may be of benefit to individuals who need it without increasing their risk for heart attacks.
Abstract
BACKGROUND Testosterone is the standard treatment for male hypogonadism, but there is uncertainty about its cardiovascular safety due to inconsistent findings. We aimed to provide the most extensive individual participant dataset (IPD) of testosterone trials available, to analyse subtypes of all cardiovascular events observed during treatment, and to investigate the effect of incorporating data from trials that did not provide IPD. METHODS We did a systematic review and meta-analysis of randomised controlled trials including IPD. We searched MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, MEDLINE Epub Ahead of Print, Embase, Science Citation Index, the Cochrane Controlled Trials Register, Cochrane Database of Systematic Reviews, and Database of Abstracts of Review of Effects for literature from 1992 onwards (date of search, Aug 27, 2018). The following inclusion criteria were applied: (1) men aged 18 years and older with a screening testosterone concentration of 12 nmol/L (350 ng/dL) or less; (2) the intervention of interest was treatment with any testosterone formulation, dose frequency, and route of administration, for a minimum duration of 3 months; (3) a comparator of placebo treatment; and (4) studies assessing the pre-specified primary or secondary outcomes of interest. Details of study design, interventions, participants, and outcome measures were extracted from published articles and anonymised IPD was requested from investigators of all identified trials. Primary outcomes were mortality, cardiovascular, and cerebrovascular events at any time during follow-up. The risk of bias was assessed using the Cochrane Risk of Bias tool. We did a one-stage meta-analysis using IPD, and a two-stage meta-analysis integrating IPD with data from studies not providing IPD. The study is registered with PROSPERO, CRD42018111005. FINDINGS 9871 citations were identified through database searches and after exclusion of duplicates and of irrelevant citations, 225 study reports were retrieved for full-text screening. 116 studies were subsequently excluded for not meeting the inclusion criteria in terms of study design and characteristics of intervention, and 35 primary studies (5601 participants, mean age 65 years, [SD 11]) reported in 109 peer-reviewed publications were deemed suitable for inclusion. Of these, 17 studies (49%) provided IPD (3431 participants, mean duration 9·5 months) from nine different countries while 18 did not provide IPD data. Risk of bias was judged to be low in most IPD studies (71%). Fewer deaths occurred with testosterone treatment (six [0·4%] of 1621) than placebo (12 [0·8%] of 1537) without significant differences between groups (odds ratio [OR] 0·46 [95% CI 0·17-1·24]; p=0·13). Cardiovascular risk was similar during testosterone treatment (120 [7·5%] of 1601 events) and placebo treatment (110 [7·2%] of 1519 events; OR 1·07 [95% CI 0·81-1·42]; p=0·62). Frequently occurring cardiovascular events included arrhythmia (52 of 166 vs 47 of 176), coronary heart disease (33 of 166 vs 33 of 176), heart failure (22 of 166 vs 28 of 176), and myocardial infarction (10 of 166 vs 16 of 176). Overall, patient age (interaction 0·97 [99% CI 0·92-1·03]; p=0·17), baseline testosterone (interaction 0·97 [0·82-1·15]; p=0·69), smoking status (interaction 1·68 [0·41-6·88]; p=0.35), or diabetes status (interaction 2·08 [0·89-4·82; p=0·025) were not associated with cardiovascular risk. INTERPRETATION We found no evidence that testosterone increased short-term to medium-term cardiovascular risks in men with hypogonadism, but there is a paucity of data evaluating its long-term safety. Long-term data are needed to fully evaluate the safety of testosterone. FUNDING National Institute for Health Research Health Technology Assessment Programme.
2.
Molecular Regulators of Muscle Mass and Mitochondrial Remodeling Are Not Influenced by Testosterone Administration in Young Women.
Horwath, O, Moberg, M, Hirschberg, AL, Ekblom, B, Apró, W
Frontiers in endocrinology. 2022;13:874748
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Testosterone is a sex hormone normally found in higher amounts in adult males than females. Testosterone plays a number of important roles, including influencing muscle size and strength. Treatment with testosterone has been shown to increase lean mass and muscle strength in women as well as men. However, female-only studies are limited, and the precise mechanisms underlying these changes are not well understood. This randomised control trial examined the effect of testosterone administration on regulators of muscle protein turnover and mitochondrial function in muscle samples collected from young women. 48 healthy, pre-menopausal women were assigned to receive either 10mg of transdermal testosterone gel per day, or a placebo, for 10 weeks. Muscle samples were collected via biopsy before and after the intervention. Testosterone administration did not appear to have a significant effect on androgen receptors, 5-alpha reductase, anabolic signalling, or mitochondrial remodelling in muscle tissue. The researchers concluded that improvements in muscle size and oxidative capacity following testosterone administration cannot be explained by changes in protein expression related to muscle protein turnover or mitochondrial remodelling. The authors went on to suggest that the small sample size in this study may have reduced the ability to detect small but biologically relevant changes in protein levels. Within the research, there is large variability among studies in terms of sex, age, route of administration and length of treatment, which makes putting these findings into context of the wider literature difficult.
Abstract
Testosterone (T) administration has previously been shown to improve muscle size and oxidative capacity. However, the molecular mechanisms underlying these adaptations in human skeletal muscle remain to be determined. Here, we examined the effect of moderate-dose T administration on molecular regulators of muscle protein turnover and mitochondrial remodeling in muscle samples collected from young women. Forty-eight healthy, physically active, young women (28 ± 4 years) were assigned in a random double-blind fashion to receive either T (10 mg/day) or placebo for 10-weeks. Muscle biopsies collected before and after the intervention period were divided into sub-cellular fractions and total protein levels of molecular regulators of muscle protein turnover and mitochondrial remodeling were analyzed using Western blotting. T administration had no effect on androgen receptor or 5α-reductase levels, nor on proteins involved in the mTORC1-signaling pathway (mTOR, S6K1, eEF2 and RPS6). Neither did it affect the abundance of proteins associated with proteasomal protein degradation (MAFbx, MuRF-1 and UBR5) and autophagy-lysosomal degradation (AMPK, ULK1 and p62). T administration also had no effect on proteins in the mitochondria enriched fraction regulating mitophagy (Beclin, BNIP3, LC3B-I, LC3B-II and LC3B-II/I ratio) and morphology (Mitofilin), and it did not alter the expression of mitochondrial fission- (FIS1 and DRP1) or fusion factors (OPA1 and MFN2). In summary, these data indicate that improvements in muscle size and oxidative capacity in young women in response to moderate-dose T administration cannot be explained by alterations in total expression of molecular factors known to regulate muscle protein turnover or mitochondrial remodeling.
3.
Testosterone Deficiency, Weakness, and Multimorbidity in Men.
Peterson, MD, Belakovskiy, A, McGrath, R, Yarrow, JF
Scientific reports. 2018;8(1):5897
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With age, the occurrence of total testosterone (TT) deficiency in men also increases. Such deficiency can have a detrimental impact on the musculoskeletal system leading to bone and muscle loss, increasing the risk of cardiovascular disease and all-cause mortality. Hence muscle weakness is a known a predicitve factor for chronic disease. Whereby reference ranges have been set for testosterone levels in young healthy men, uncertainty exists about optimal levels throughout different age ranges, ethnicities and in concurrence with diseases. This observational study evaluated how TT deficiency and muscle weakness assessed via grip strength, relates to chronic health conditions in men. The study included 2399 young, middle-aged, and older men in the US, with a diverse ethnic backgrounds, who presented with and without testosterone deficiency. The findings indicated that TT levels were highest amongst young men, yet no particular difference was seen in levels between middle-aged and older men. Grip strength decreased in the higher age categories. Chronic health conditions were more common in young and older men who displayed testosterone deficiencies, whilst low testosterone and reduced grip strength were linked to the presence of chronic disease in all age groups. Overall the study confirmed previous research, that in men with testosterone deficiency chronic disease was much more prevalent, even after accounting for other variables. The study also observed a much lower average of TT levels in young men compared to previous research, in mostly white males. Thus testosterone deficiency appears much more common in men of all ages when including a variety of ethnic groups. As low testosterone may play an early, causal role in the chronic disease process, continuous monitoring of testosterone levels through the life span may aid the early identification of chronic disease development or disease progression. Further research is needed on the independent and joint effects of low TT and muscular weakness. From a clinical perspective, this study affirms that low testosterone in men is a presenting risk factor for chronic disease and that chronic disease is commonly accompanied by low testosterone. It also highlights some unsettled aspects around reference ranges of testosterone
Abstract
The purposes of this study were to evaluate the association between total testosterone (TT) deficiency and weakness on multimorbidity in men. Analyses were performed to examine the prevalence of multimobidity among young, middle-aged, and older men, with and without testosterone deficiency. Multivariate logistic models were also used to determine the association between age-specific TT tertiles and multimorbidity, adjusting for key sociodemographic variables, as well as a secondary analysis adjusted for grip strength. Multimorbidity was more prevalent among men with testosterone deficiency, compared to normal TT in the entire group (36.6% vs 55.2%; p < 0.001); however, differences were only seen within young (testosterone deficiency: 36.4%; normal TT: 13.5%; p < 0.001) and older men (testosterone deficiency: 75.0%; normal TT: 61.5%; p < 0.001). Robust associations were found between the age-specific low-TT (OR: 2.87; 95%CI: 2.14-3.83) and moderate-TT (OR: 1.67; 95%CI: 1.27-2.20) tertiles (reference high-TT) and multimorbidity. Secondary analysis demonstrated that both low TT (OR: 1.82; 95%CI: 1.29-2.55) and moderate-TT (OR: 1.31; 95%CI: 1.01-1.69) were associated with multimorbidity, even after adjusting for obesity (OR: 1.75; 95%CI: 1.07-2.87) and NGS (OR: 1.21 per 0.05 unit lower NGS). Low TT and weakness in men were independently associated with multimorbidity at all ages; however, multimorbidity was more prevalent among young and older men with testosterone deficiency.
4.
Hormonal and metabolic effects of polyunsaturated fatty acids in young women with polycystic ovary syndrome: results from a cross-sectional analysis and a randomized, placebo-controlled, crossover trial.
Phelan, N, O'Connor, A, Kyaw Tun, T, Correia, N, Boran, G, Roche, HM, Gibney, J
The American journal of clinical nutrition. 2011;93(3):652-62
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5-10% of women of reproductive age are thought to be affected by polycystic ovary syndrome (PCOS). Women with PCOS don’t ovulate and have high levels of androgens (‘male’ hormones) such as testosterone. Dietary changes are often recommended for women with PCOS, yet the optimal diet for managing the condition has not been defined. Long-chain polyunsaturated fatty acids (PUFAs), in particular omega-3s, may influence various aspects of metabolic health in ways that are beneficial for women with PCOS. The objectives of this study were to determine the link between PUFAs and hormonal aspects of PCOS, to investigate the effects of omega-3 supplementation, and to support the findings with cellular studies. Participants were given 4 mg of either omega-3 supplementation or an olive oil placebo every day for 6 weeks. There was a 6-week rest period, after which the women crossed over to receive the alternative treatment for a further 6 weeks. Women who had higher levels of circulating androgens at the start of the study tended to have both higher omega-6 levels and omega-6:omega-3 ratios. After taking omega-3 supplements, testosterone levels were significantly reduced, particularly in those women who experienced more substantial falls in the ratio of omega-6:omega-3. Alongside this, the researchers found that ovarian cells sourced from cows increased production of androgens when treated with omega-6, but not omega-3. The authors concluded that supplementation with omega-3 PUFAs improves hormonal balance in women with PCOS.
Abstract
BACKGROUND Polycystic ovary syndrome (PCOS) is characterized by an adverse metabolic profile. Although dietary changes are advocated, optimal nutritional management remains uncertain. Polyunsaturated fatty acids (PUFAs), particularly long-chain (LC) n-3 (omega-3) PUFAs, improve metabolic health, but their therapeutic potential in PCOS is unknown. OBJECTIVES We aimed to determine the associations between plasma PUFAs and metabolic and hormonal aspects of PCOS to investigate the efficacy of LC n-3 PUFA supplementation and to support the findings with mechanistic cellular studies. DESIGN We selected a cross-sectional PCOS cohort (n = 104) and conducted a principal component analysis on plasma fatty acid profiles. Effects of LC n-3 PUFA supplementation on fasting and postprandial metabolic and hormonal markers were determined in PCOS subjects (n = 22) by a randomized, crossover, placebo-controlled intervention. Direct effects of n-6 (omega-6) compared with n-3 PUFAs on steroidogenesis were investigated in primary bovine theca cells. RESULTS Cross-sectional data showed that a greater plasma n-6 PUFA concentration and n-6:n-3 PUFA ratio were associated with higher circulating androgens and that plasma LC n-3 PUFA status was associated with a less atherogenic lipid profile. LC n-3 PUFA supplementation reduced plasma bioavailable testosterone concentrations (P < 0.05), with the greatest reductions in subjects who exhibited greater reductions in plasma n-6:n-3 PUFA ratios. The treatment of bovine theca cells with n-6 rather than with n-3 PUFAs up-regulated androstenedione secretion (P < 0.05). CONCLUSIONS Cross-sectional data suggest that PUFAs modulated hormonal and lipid profiles and that supplementation with LC n-3 PUFAs improves androgenic profiles in PCOS. In bovine theca cells, arachidonic acid modulated androstenedione secretion, which suggests an indirect effect of n-3 PUFAs through the displacement of or increased competition with n-6 PUFAs. This trial was registered at clinicaltrials.gov as NCT01189669.