The Association of Free Testosterone Levels in Men and Lifestyle Factors and Chronic Disease Status: A North Texas Healthy Heart Study

The association of serum testosterone with dyslipidemia is mediated by obesity: the Henan Rural Cohort Study

BACKGROUND AND AIMS

This study aimed to evaluate the relationships of serum testosterone with dyslipidemia and blood lipid levels and test whether obesity mediated these associations by gender in Chinese rural population.

METHODS AND RESULTS

A total of 6150 subjects were finally analyzed in this study. Serum testosterone for each subject was detected by liquid chromatography equipped with tandem mass spectrometry. Logistic regression and linear regression were employed to evaluate the associations of serum testosterone with the prevalence of dyslipidemia and blood lipid levels. Mediation analysis was conducted to identify the mediation effects of obesity on the relationship between serum testosterone and dyslipidemia. After adjusting for multiple confounders, per unit change in serum ln-testosterone levels was associated with a decreased prevalent dyslipidemia in men (odds ratio (OR): 0.785, 95% confidence interval (CI) (0.708, 0.871)). Males with the levels of serum testosterone in the third or fourth quartiles had a 49.4% (OR: 0.506, 95% CI 0.398, 0.644) or 67.1% (OR: 0.329, 95% CI 0.253, 0.428) significantly lower odds of prevalence of dyslipidemia. In addition, a onefold increase in ln-testosterone was related to a 0.043 mmol/L (95% CI 0.028, 0.059) increase in high-density lipoprotein cholesterol (HDL-C) in men. Results of the mediation analysis suggested that obesity played a partial role in the association of testosterone with dyslipidemia in men.

CONCLUSIONS

These findings suggested that serum testosterone levels were negatively associated with lipid levels and prevalent dyslipidemia, and obesity mediated the effects of serum testosterone on dyslipidemia in men, implying that obesity prevention should be highlighted to decrease the prevalence of dyslipidemia related to changes in testosterone levels.

Examining the effects of calorie restriction on testosterone concentrations in men: a systematic review and meta-analysis

CONTEXT

Testosterone concentrations decline with age, and lower testosterone concentrations are associated with several morbidities, including sexual dysfunction, obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome.

OBJECTIVE

Because dietary habits play a critical role in weight regulation and T2DM management, the aim of this systematic review and meta-analysis was to summarize and critically evaluate the evidence from randomized controlled trials to determine the effects of calorie restriction (CR) on testosterone concentrations in men.

DATA SOURCES

A literature search was conducted across 4 databases, from their inception until March 2020.

DATA EXTRACTION

The screening and data extraction were completed by 2 authors independently, and in a blinded manner, according to a priori inclusion and exclusion criteria.

DATA ANALYSIS

Of the 4198 studies identified from the initial search, 7 randomized controlled trials were included for data extraction. Significant increases in total testosterone concentrations were reported in 3 of 4 studies in which CR was examined with overweight or obese men, compared with the control groups. Significant decreases in total testosterone concentrations were reported in 2 of 3 studies in which the effects of CR were examined with normal-weight, healthy men, compared with the control groups. In all 4 studies that examined the effect of CR on sex hormone-binding globulin concentrations, the intervention significantly increased sex hormone-binding globulin concentrations compared with that of the control groups irrespective of body composition.

CONCLUSION

This systematic review and meta-analysis provide some evidence that CR affects testosterone concentrations in men and this effect depends on their body mass index. PROSPERO registration no. CRD42020173102.

Metals Content in Herbal Supplements

Obesity has become an international epidemic. To evaluate the level of metals in extracts of plants prescribed as weight loss supplements, different brands containing Camellia sinensis (L.) Kuntze, Citrus aurantium L., Cordia ecalyculata Vell, Ilex paraguariensis A. St.-Hil, Cissus quadrangularis L., Senna alexandrina Mill were purchased in local market, hot acid digested, and analyzed while metal content by inductively coupled plasma optical emission spectrometry, ICP-OES. Quality assurance and quality control tests were carried out in order to monitor and control the reliability of the analytical method. For each metal evaluated, a calibration curve was prepared with certified reference material. The recovery test was performed for each batch of samples. Analyses were performed in triplicate. Quantification of aluminum, barium, cadmium, cobalt, chromium, copper, iron, lithium, manganese, molybdenum, nickel, lead, vanadium, and zinc were determined. The metals most frequently detected were manganese (15.3-329,60 mg kg^-1) aluminum (11.76-342.4 mg kg^-1), and iron (11.14-73.01 mg kg^-1) with higher levels in products containing C. sinensis China origin, I. paraguariensis Brazilian origin, C. quadrangularis, and C. aurantium China origin, respectively. To ensure safety consumption, an adequacy of the certification of Brazilian suppliers for herbal weight loss products is indispensable.

Efficacy and safety of testosterone replacement therapy in men with hypogonadism: A meta-analysis study of placebo-controlled trials

The purpose of the present meta-analysis was to evaluate the efficacy and safety of testosterone replacement therapy in men with hypogonadism. A search was conducted for appropriate randomized controlled trials and the data from 16 trials were pooled. The intended primary outcome of the present study was to determine the efficacy and safety of testosterone replacement therapy. The current data demonstrated that scores for Aging Male Symptoms (AMS) were significantly reduced following testosterone replacement therapy, with a mean decrease in AMS score of 1.52 [95% confidence interval (CI), 0.72 to 2.32; P=0.0002]. Testosterone replacement therapy increased lean body mass [mean difference (MD), 1.22; 95% CI, 0.33 to 2.11; P=0.007], reduced fat mass in a non-significantly manner (MD, −0.85; 95% CI, −1.74 to 0.04; P=0.06) and significantly reduced total cholesterol (MD, −0.16; 95% CI, −0.29 to −0.03; P=0.01). No significant differences were identified in body weight (MD, 0.09; 95% CI, −1.13 to 1.31; P=0.89), body mass index (MD, 0.10; 95% CI, −0.62 to 0.82; P=0.78) or bone mineral density (MD, −0.01; 95% CI, −0.03 to 0.02; P=0.60). Average prostate volume increased (MD, 1.58; 95% CI, 0.6 to 2.56; P=0.002) following testosterone replacement therapy, but the levels of prostate-specific antigen (PSA) (MD, 0.10; 95% CI, −0.03 to 0.22; P=0.14) and the International Prostate Symptom Scores (MD, 0.01; 95% CI, −0.37 to 0.39; P=0.96) did not change. In conclusion, testosterone replacement therapy improves quality of life, increases lean body mass, significantly decreases total cholesterol, and is well-tolerated and safe for men with hypogonadism who are exhibiting PSA levels of <4 ng/ml.

Association of Free Testosterone With Hypogonadal Symptoms in Men With Near-normal Total Testosterone Levels

OBJECTIVE

To investigate the association between hypogonadal symptoms and free testosterone (FT) levels in men with near-normal total testosterone (T) levels (250-350 ng/dL) and to determine whether a discriminatory threshold for FT exists below which hypogonadal symptoms become more prevalent.

METHODS

We reviewed the charts of 3167 men who presented to an outpatient men's health clinic. Two hundred thirty-one men had symptoms of "low testosterone" and serum testosterone levels between 250 and 350 ng/dL. We evaluated hypogonadal symptoms using the Androgen Deficiency in the Adult Male (ADAM) and quantitative ADAM (qADAM) questionnaires. Serum levels of T and sex hormone-binding globulin were collected on the same day that men completed their questionnaires. We used linear regression to determine whether a threshold of FT exists for hypogonadal symptoms. We performed univariate and multivariable analyses to evaluate factors that predicted a low FT level.

RESULTS

The median age was 43.5 years, and the median testosterone and FT levels were 303 ng/dL and 6.3 ng/dL, respectively. Prevalence and severity of hypogonadal symptoms (ADAM and qADAM) were similar between men with low (<6.4 ng/mL) and normal FT levels. There was an association between age and 3 of the 10 hypogonadal symptoms (decreased enjoyment in life, sadness, and deterioration of work performance) with a low FT on a univariate analysis. Only younger age was positively associated with FT on multivariable analysis.

CONCLUSION

We did not observe a relationship between hypogonadal symptoms and FT in men with near-normal testosterone levels. Symptom-specific FT thresholds could not be defined, as age remains an important confounder.