Associations of endogenous testosterone and lipid profiles in middle-aged to older Taiwanese men

Cardiovascular disease and testosterone therapy in male hypogonadism

This review assesses the evidence of the physiological effects of testosterone on cardiovascular health, the association between male hypogonadism and cardiovascular health, and the effects of testosterone therapy on cardiovascular health in male hypogonadism. Preclinical studies suggest complex effects of testosterone on cardiovascular risk by acting on skeletal muscle, cardiomyocytes, vasculature, adipocytes, insulin action, and erythropoiesis. Furthermore, low testosterone has a bi-directional association with cardiometabolic risk. Observational studies have reported worse metabolic profiles in men with organic hypogonadism. However, a consistent association between major cardiovascular events and male hypogonadism has not been established. Hematocrit increases with testosterone therapy; however, most studies do not report an increase in venous thromboembolism risk. Although some observational studies and a small randomized controlled study reported an increased risk of cardiovascular disease, recent data confirm the medium-term cardiovascular safety of testosterone therapy in middle-aged and older men with low testosterone.

Non-linear association between testosterone and LDL concentrations in men

BACKGROUND

Contradictory data have been reported about the association between testosterone levels and the levels of low-density lipoprotein cholesterol (LDL).

OBJECTIVES

The aim of this study was to elucidate the association between testosterone and LDL levels.

MATERIALS AND METHODS

A cross-sectional study was conducted that included 7268 men who had participated in a health examination. Men who took agents that influence serum lipid profiles within the previous 6 months were excluded. A full metabolic work-up and serum testosterone level checks were performed. The main outcome measures included the testosterone level and testosterone <3.5 ng/ml prevalence of each decile of LDL and their polynomial trendlines and the odds ratio (OR) of testosterone <3.5 ng/ml according to the LDL level.

RESULTS

The polynomial trendline suggests the inverse association of testosterone with the deciles of triglycerides, the positive association of testosterone with the deciles of high-density lipoprotein cholesterol and the inverted U-shaped association between testosterone and the deciles of LDL. The polynomial trendline suggests a U-shaped curvilinear relationship between the deciles of LDL and the prevalence of testosterone <3.5 ng/ml. The adjusted ORs of testosterone <3.5 ng/ml in men in the lowest and highest deciles were significantly higher than those of men in the 10th-90th deciles of LDL (OR [95% CI], < 10th LDL: 1.4[1.2-1.8]; 10th - 90th LDL: 1.0 [reference]; >90th LDL: 1.3[1.0-1.6]), which reinforces the U-shaped curvilinear relationship between LDL levels and the prevalence of testosterone <3.5 ng/ml.

DISCUSSION AND CONCLUSION

Further research is needed to elucidate the association of very low or very high LDL concentrations with circulating testosterone in men.

Association between metabolic syndrome, hepatic steatosis, and testosterone deficiency: evidences from studies with men and rodents

Testosterone is the predominant androgen in men and the lack of it can be a trigger to the development of the metabolic syndrome. Here we review the relationship between testosterone deficiency, metabolic syndrome, and hepatic steatosis reported by studies with men and rodents. The prevalence of metabolic syndrome and testosterone deficiency is higher among older subjects. Low total and free testosterone levels were positively associated with disturbs on energy metabolism, changes in body fat distribution, and body composition. Studies reported visceral fat accumulation in men with hypogonadism and castrated rats. Despite some contradictions, the association between higher adiposity, low testosterone, and metabolic syndrome was a common point among the studies. Few studies evaluated the hepatic steatosis and found an association with hypogonadism. Most of the studies with rodents combined the castration with a high-fat diet to study metabolic disturbs. The importance of proper levels of testosterone for energy metabolism homeostasis in men was also underlined by studies that investigated the metabolic effects of testosterone replacement therapy and androgen deprivation therapy.

Benefits and Health Implications of Testosterone Therapy in Men With Testosterone Deficiency

INTRODUCTION

Testosterone (T) deficiency (TD; hypogonadism) has deleterious effects on men's health; negatively affects glycometabolic and cardiometabolic functions, body composition, and bone mineral density; contributes to anemia and sexual dysfunction; and lowers quality of life. T therapy (TTh) has been used for the past 8 decades to treat TD, with positive effects on signs and symptoms of TD.

AIM

To summarize the health benefits of TTh in men with TD.

METHODS

A comprehensive literature search was carried out using PubMed, articles relevant to TTh were accessed and evaluated, and a comprehensive summary was synthesized.

MAIN OUTCOME MEASURES

Improvements in signs and symptoms of TD reported in observational studies, registries, clinical trials, and meta-analyses were reviewed and summarized.

RESULTS

A large body of evidence provides significant valuable information pertaining to the therapeutic value of TTh in men with TD. TTh in men with TD provides real health benefits for bone mineral density, anemia, sexual function, glycometabolic and cardiometabolic function, and improvements in body composition, anthropometric parameters, and quality of life.

CONCLUSION

TTh in the physiologic range for men with TD is a safe and effective therapeutic modality and imparts great benefits on men's health and quality of life. Traish AM. Benefits and Health Implications of Testosterone Therapy in Men With Testosterone Deficiency. Sex Med Rev 2018;6:86-105.

Adverse health effects of testosterone deficiency (TD) in men

Testosterone and its metabolite, 5α-dihydrotestosterone are critical metabolic and vascular hormones, which regulate a host of biochemical pathways including carbohydrate, lipid and protein metabolism and modulate vascular function. Testosterone deficiency (TD) is a well-recognized medical condition with important health implications. TD is associated with a number of co-morbidities including increased body weight, adiposity and increased waist circumference, insulin resistance (IR) and type 2 diabetes mellitus (T2DM), hypertension, inflammation, atherosclerosis and cardiovascular disease, erectile dysfunction (ED) and increased incidence of mortality. In this review, we summarize the data in the literature on the prevalence of TD and its association with the various co-morbidities and suggest that T therapy is necessary to improve health outcomes in men with TD.

Long-term testosterone therapy in hypogonadal men ameliorates elements of the metabolic syndrome: an observational, long-term registry study

AIM

The goal of this study was to determine if long-term testosterone (T) therapy in men with hypogonadism, henceforth referred to as testosterone deficiency (TD), ameliorates or improves metabolic syndrome (MetS) components.

METHODS

We performed a cumulative registry study of 255 men, aged between 33 and 69 years (mean 58.02 ± 6.30) with subnormal plasma total T levels (mean: 9.93 ± 1.38; range: 5.89-12.13 nmol/l) as well as at least mild symptoms of TD assessed by the Aging Males' symptoms scale. All men received treatment with parenteral T undecanoate 1000 mg (Nebido(®) , Bayer Pharma, Berlin, Germany), administered at baseline and 6 weeks and thereafter every 12 weeks for up to 60 months. Lipids, glucose, liver enzymes and haemoglobin A1c analyses were carried out in a commercial laboratory. Anthropometric measurements were also made throughout the study period.

RESULTS

Testosterone therapy restored physiological T levels and resulted in reductions in total cholesterol (TC) [7.29 ± 1.03 to 4.87 ± 0.29 mmol/l (281.58 ± 39.8 to 188.12 ± 11.31 mg/dl)], low-density lipoprotein cholesterol [4.24 ± 1.07 to 2.84 ± 0.92 mmol/l (163.79 ± 41.44 to 109.84 ± 35.41 mg/dl)], triglycerides [3.14 ± 0.58 to 2.16 ± 0.13 mmol/l (276.16 ± 51.32 to 189.78 ± 11.33 mg/dl)] and increased high-density lipoprotein levels [1.45 ± 0.46 to 1.52 ± 0.45 mmol/l (56.17 ± 17.79 to 58.85 ± 17.51 mg/dl)] (p < 0.0001 for all). There were marked reductions in systolic and diastolic blood pressure, blood glucose, haemoglobin A1c , C-reactive protein (6.29 ± 7.96 to 1.03 ± 1.87 U/l), alanine aminotransferase and aspartate aminotransferase (p < 0.0001 for all).

CONCLUSIONS

Long-term T therapy, at physiological levels, ameliorates MetS components. These findings strongly suggest that T therapy in hypogonadal men may prove useful in reducing the risk of cardiometabolic diseases.

The prevalence and predictors of androgen deficiency in Taiwanese men with type 2 diabetes

OBJECTIVE

To evaluate the prevalence and predictors of androgen deficiency (AD) in Taiwanese men with type 2 diabetes mellitus (T2DM).

METHODS

A recent hospital-based series of Western populations showed that 30%-50% of men with T2DM have low testosterone, and AD links to DM and obesity bidirectionally. However, data of AD from other ethnicities with character of less obesity are rarely reported. AD was defined as having a total testosterone level less than 300 ng/dL. The clinical variables and diabetes-associated complications of the risk of AD were evaluated.

RESULTS

Of 766 consecutive subjects (mean age 62.2 years, mean body mass index [BMI] 26.0) attending out-patient diabetic clinics, 32.5% have AD. The AD group was older, had higher BMI, waist circumference, higher proportion of metabolic syndrome and stroke, higher levels of triglyceride, high sensitivity C-reactive protein (hsCRP), uric acid, and lower levels of total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) than the normal testosterone group. After age adjustment, AD was positively associated with metabolic syndrome (odds ratio [OR] = 2.142), serum high sensitivity C-reactive protein (OR = 1.120), uric acid (OR = 1.118), BMI (OR = 1.083), waist circumference (OR = 1.038), triglyceride (OR = 1.028), and inversely associated with serum low-density lipoprotein (OR = 0.931) and high-density lipoprotein (OR = 0.826) in logistic regression analysis. There were no significant differences in retinopathy, neuropathy, nephropathy, or coronary artery disease between patients with or without AD.

CONCLUSION

One third of Taiwanese men with T2DM have AD. The major predictors of AD are linked to obesity, which is a potentially modifiable risk factor, and may represent an important avenue for intervention.