Systematic review and meta-analyses on associations of endogenous testosterone concentration with health outcomes in community-dwelling men

Association between phthalates exposure and myocardial damage in the general population: A cross-sectional study

BACKGROUND

Cardiovascular consequences of phthalates exposure have been given increasing attention, but the association of phthalates with subclinical cardiovascular disease (CVD) was unknown. Accordingly, this study aimed to investigate the association between phthalates exposure and high-sensitivity cardiac troponin I (hs-cTnI), a marker of myocardial injury, which was detectable in the subclinical stage of CVD.

METHODS

Participants aged 6 years or older with available urinary phthalates metabolites and serum hs-cTnI concentrations were included in the National Health and Nutrition Examination Survey 2003-2004 cycle. Multivariable linear regression and weighted quantiles sum (WQS) regression were used to assess the association of hs-cTnI with individual phthalates and their co-exposure. Di-2-ethylhexylphthalate (ΣDEHP), high-molecular-weight phthalate (ΣHMWP), and low-molecular-weight phthalate (ΣLMWP) were defined as the molecular sum of phthalates metabolites in urine.

RESULTS

2241 participants were finally included. The percent change of serum hs-cTnI concentrations related to per 1-standard deviation increase of logarithmic urinary phthalates concentrations was 3.4% (0.1-6.7, P = 0.04) for ΣDEHP, 3.6% (0.3-6.9, P = 0.03) for ΣHMWP, and 3.5% (0.2-6.8, P = 0.04) for ΣLMWP. Co-exposure to phthalates metabolites expressed as the WQS index also demonstrated a positive association with hs-cTnI. A similar association pattern was found in the population with no prior CVD.

CONCLUSIONS

This study indicated the potential of phthalates to myocardial injury which may occur even before clinically apparent CVD was identified, emphasizing the significance of reducing phthalates in the prevention of CVD.

Sociodemographic, lifestyle, and medical factors associated with calculated free testosterone concentrations in men: individual participant data meta-analyses

OBJECTIVE

Sociodemographic, lifestyle, and medical variables influence total testosterone (T) and sex hormone-binding globulin (SHBG) concentrations. The relationship between these factors and "free" T remains unclear. We examined 21 sociodemographic, lifestyle, and medical predictors influencing calculated free T (cFT) in community-dwelling men across ages.

DESIGN

This is a cross-sectional analysis in 20 631 participants in the Androgens in Men Study.

METHODS

Individual participant data (IPD) were provided by 9 cohorts. Total T was determined using mass spectrometry, SHBG using immunoassays, and cFT using the Vermeulen formula. Associations were analyzed using 2-stage random effects IPD meta-analyses.

RESULTS

Cohort median ages ranged from 40 to 76 years and median cFT concentrations from 174.3 to 422.8 pmol/L. In men aged 17-99 years, there was a linear inverse association of cFT with age (-57.2 pmol/L [95% confidence interval, -69.4, -44.9] per 1 SD increase in age). Calculated free T increased with increasing baseline body mass index (BMI) among men with BMI < 23.6 kg/m2, but decreased among men with BMI > 23.6 kg/m2 (-24.7 pmol/L [-29.1, -20.3] per 1 SD increase in the 25.4-29.6 kg/m2 BMI range). Calculated free T was lower in younger men, who were married or in a de facto relationship (-18.4 pmol/L [-27.6, -9.3]) and in men who formerly smoked (-5.7 pmol/L [-8.9, -2.6]), were in poor general health (-14.0 pmol/L [-20.1, -7.8]), and had diabetes (-19.6 pmol/L [-23.0, -16.3]), cardiovascular disease (-5.8 pmol/L [-8.3, -3.2]), or cancer (-19.2 pmol/L [-24.4, -14.1]).

CONCLUSIONS

Calculated free T was most prominently associated with age and BMI. The linear, inverse association with age, nonlinear association with BMI, and presence of diabetes, cancer, and sociodemographic factors should be considered when interpreting cFT values.

Association of total and free testosterone with cardiovascular disease in a nationally representative sample of white, black, and Mexican American men

Associations of total testosterone (T) and calculated free T with cardiovascular disease (CVD) remain poorly understood. Particularly how these associations vary according to race and ethnicity in a nationally representative sample of men. Data included 7058 men (≥20 years) from NHANES. CVD was defined as any reported diagnosis of heart failure (HF), coronary artery disease (CAD), myocardial infarction (MI), and stroke. Total T (ng/mL) was obtained among males who participated in the morning examination. Weighted multivariable-adjusted logistic regression models were conducted. We found associations of low T (OR = 1.57, 95% CI = 1.17-2.11), low calculated free T (OR = 1.53, 95% CI = 1.10-2.17), total T (Q1 vs Q5), and calculated free T (Q1 vs Q5) with CVD after adjusting for estradiol and SHBG. In disease specific analysis, low T increased prevalence of MI (OR = 1.72, 95% CI = 1.08-2.75) and HF (OR = 1.74, 95% CI = 1.08-2.82), but a continuous increment of total T reduced the prevalence of CAD. Similar inverse associations were identified among White and Mexican Americans, but not Blacks (OR = 0.93, 95% CI = 0.49-1.76). Low levels of T and calculated free T were associated with an increased prevalence of overall CVD and among White and Mexican Americans. Associations remained in the same direction with specific CVD outcomes in the overall population.

Associations of Testosterone and Related Hormones With All-Cause and Cardiovascular Mortality and Incident Cardiovascular Disease in Men : Individual Participant Data Meta-analyses

BACKGROUND

Whether circulating sex hormones modulate mortality and cardiovascular disease (CVD) risk in aging men is controversial.

PURPOSE

To clarify associations of sex hormones with these outcomes.

DATA SOURCES

Systematic literature review to July 2019, with bridge searches to March 2024.

STUDY SELECTION

Prospective cohort studies of community-dwelling men with sex steroids measured using mass spectrometry and at least 5 years of follow-up.

DATA EXTRACTION

Independent variables were testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone (DHT), and estradiol concentrations. Primary outcomes were all-cause mortality, CVD death, and incident CVD events. Covariates included age, body mass index, marital status, alcohol consumption, smoking, physical activity, hypertension, diabetes, creatinine concentration, ratio of total to high-density lipoprotein cholesterol, and lipid medication use.

DATA SYNTHESIS

Nine studies provided individual participant data (IPD) (255 830 participant-years). Eleven studies provided summary estimates (n = 24 109). Two-stage random-effects IPD meta-analyses found that men with baseline testosterone concentrations below 7.4 nmol/L (<213 ng/dL), LH concentrations above 10 IU/L, or estradiol concentrations below 5.1 pmol/L had higher all-cause mortality, and those with testosterone concentrations below 5.3 nmol/L (<153 ng/dL) had higher CVD mortality risk. Lower SHBG concentration was associated with lower all-cause mortality (median for quintile 1 [Q1] vs. Q5, 20.6 vs. 68.3 nmol/L; adjusted hazard ratio [HR], 0.85 [95% CI, 0.77 to 0.95]) and lower CVD mortality (adjusted HR, 0.81 [CI, 0.65 to 1.00]). Men with lower baseline DHT concentrations had higher risk for all-cause mortality (median for Q1 vs. Q5, 0.69 vs. 2.45 nmol/L; adjusted HR, 1.19 [CI, 1.08 to 1.30]) and CVD mortality (adjusted HR, 1.29 [CI, 1.03 to 1.61]), and risk also increased with DHT concentrations above 2.45 nmol/L. Men with DHT concentrations below 0.59 nmol/L had increased risk for incident CVD events.

LIMITATIONS

Observational study design, heterogeneity among studies, and imputation of missing data.

CONCLUSION

Men with low testosterone, high LH, or very low estradiol concentrations had increased all-cause mortality. SHBG concentration was positively associated and DHT concentration was nonlinearly associated with all-cause and CVD mortality.

PRIMARY FUNDING SOURCE

Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668).

Testosterone and aging male, a perspective from a developing country

PURPOSE

Hypogonadism is associated with a wide range of physical and psychological symptoms that can affect the overall health of men. However, in a developing country, there are several imposing challenges in the diagnosis and treatment of hypogonadism, including a lack of awareness and understanding of the condition among healthcare providers and patients, limited resources and the high cost of treatment. This review aimed to examine the potential benefits and risks of testosterone replacement therapy (TRT) and provides a perspective of a developing country on the topic.

MATERIALS AND METHODS

A comprehensive literature review was conducted to gather relevant information on the impact of testosterone deficiency on ageing males and the effectiveness of TRT for treating hypogonadism. Published peer-reviewed articles were analyzed to evaluate the benefits and risks of TRT. Additionally, the unique challenges faced in the diagnosis and treatment of hypogonadism in a developing country were considered.

RESULTS

Testosterone replacement therapy has been shown to be an effective treatment for hypogonadism, particularly in symptomatic men with low testosterone levels. It offers potential benefits such as improvements in symptoms and overall quality of life. However, there are associated risks and side effects that need to be considered. In a developing country, challenges such as limited awareness and understanding of hypogonadism, resource constraints, and high treatment costs pose additional barriers to accessing TRT and comprehensive care.

CONCLUSION

In conclusion, TRT holds promise as a treatment for hypogonadism, but its implementation and accessibility face significant challenges in a developing country. Addressing these challenges, including raising awareness, allocating resources, and finding cost-effective solutions, is crucial for ensuring that men with hypogonadism in such settings receive appropriate diagnosis and treatment. Further research and efforts are needed to improve the management of hypogonadism in developing countries and optimize the potential benefits of TRT for affected individuals.

Factors Associated With Circulating Sex Hormones in Men : Individual Participant Data Meta-analyses

BACKGROUND

Various factors modulate circulating testosterone in men, affecting interpretation of testosterone measurements.

PURPOSE

To clarify factors associated with variations in sex hormone concentrations.

DATA SOURCES

Systematic literature searches (to July 2019).

STUDY SELECTION

Prospective cohort studies of community-dwelling men with total testosterone measured using mass spectrometry.

DATA EXTRACTION

Individual participant data (IPD) (9 studies; n = 21 074) and aggregate data (2 studies; n = 4075). Sociodemographic, lifestyle, and health factors and concentrations of total testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone, and estradiol were extracted.

DATA SYNTHESIS

Two-stage random-effects IPD meta-analyses found a nonlinear association of testosterone with age, with negligible change among men aged 17 to 70 years (change per SD increase about the midpoint, -0.27 nmol/L [-7.8 ng/dL] [CI, -0.71 to 0.18 nmol/L {-20.5 to 5.2 ng/dL}]) and decreasing testosterone levels with age for men older than 70 years (-1.55 nmol/L [-44.7 ng/dL] [CI, -2.05 to -1.06 nmol/L {-59.1 to -30.6 ng/dL}]). Testosterone was inversely associated with body mass index (BMI) (change per SD increase, -2.42 nmol/L [-69.7 ng/dL] [CI, -2.70 to -2.13 nmol/L {-77.8 to -61.4 ng/dL}]). Testosterone concentrations were lower for men who were married (mean difference, -0.57 nmol/L [-16.4 ng/dL] [CI, -0.89 to -0.26 nmol/L {-25.6 to -7.5 ng/dL}]); undertook at most 75 minutes of vigorous physical activity per week (-0.51 nmol/L [-14.7 ng/dL] [CI, -0.90 to -0.13 nmol/L {-25.9 to -3.7 ng/dL}]); were former smokers (-0.34 nmol/L [-9.8 ng/dL] [CI, -0.55 to -0.12 nmol/L {-15.9 to -3.5 ng/dL}]); or had hypertension (-0.53 nmol/L [-15.3 ng/dL] [CI, -0.82 to -0.24 nmol/L {-23.6 to -6.9 ng/dL}]), cardiovascular disease (-0.35 nmol/L [-10.1 ng/dL] [CI, -0.55 to -0.15 nmol/L {-15.9 to -4.3 ng/dL}]), cancer (-1.39 nmol/L [-40.1 ng/dL] [CI, -1.79 to -0.99 nmol/L {-51.6 to -28.5 ng/dL}]), or diabetes (-1.43 nmol/L [-41.2 ng/dL] [CI, -1.65 to -1.22 nmol/L {-47.6 to -35.2 ng/dL}]). Sex hormone-binding globulin was directly associated with age and inversely associated with BMI. Luteinizing hormone was directly associated with age in men older than 70 years.

LIMITATION

Cross-sectional analysis, heterogeneity between studies and in timing of blood sampling, and imputation for missing data.

CONCLUSION

Multiple factors are associated with variation in male testosterone, SHBG, and LH concentrations. Reduced testosterone and increased LH concentrations may indicate impaired testicular function after age 70 years. Interpretation of individual testosterone measurements should account particularly for age older than 70 years, obesity, diabetes, and cancer.

PRIMARY FUNDING SOURCE

Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668).

Testicular function is associated with cardiometabolic health markers: A cross-sectional study of 2289 young men

BACKGROUND

Testicular function, including compensated Leydig cell function, has been indicated to be an early marker of morbidity.

OBJECTIVE

To study the association of testicular function and markers of metabolic and cardiovascular health in a population of young men.

MATERIALS AND METHODS

A cross-sectional study of 2289 men (median age 19 years, 5-95 percentile 18.4-22.2) from the general population examined between 2012 and 2019. Participants answered a questionnaire, had a blood sample drawn for assessment of reproductive hormone levels and health markers (lipids, glycosylated hemoglobin), delivered a semen sample, underwent physical examination including blood pressure measurements, and dual-energy X-ray absorptiometry scan for assessment of body composition. Associations were assessed in both crude and adjusted linear regression analyses.

RESULTS

The men were within the normal reference intervals of their age for reproductive and health biomarkers. Compared to the lowest quartile, having luteinizing hormone levels in the highest quartile was associated with higher mean arterial pressure (1.6 [95% confidence interval: 0.8; 2.5] mmHg), cholesterol (0.1 [95% confidence interval: 0.02; 0.18] mmol/L), and total body fat percentage (1.1 [95% confidence interval: 0.4; 1.8] %-points). Higher serum testosterone levels were associated with more advantageous cardiometabolic health markers and higher total sperm count with a healthier body composition and lower glycosylated hemoglobin.

DISCUSSION AND CONCLUSION

In this study of young men, unselected regarding reproductive hormones and semen quality, higher luteinizing hormone was associated with cardiovascular risk factors. Higher testosterone and total sperm count were associated with more favorable cardiometabolic indices. Thus, serum reproductive hormones and semen quality may be early appearing biomarkers of cardiovascular health even among young healthy men, which could potentially be useful for preventive initiatives to reduce the excess mortality and morbidity risk among infertile men. However, our study was cross-sectional and cannot determine causation. Future longitudinal studies of reproductive health in young men are warranted.

Relationships between endogenous and exogenous testosterone and cardiovascular disease in men

In this narrative review, we discuss the evidence about the controversy about the cardiovascular effects of endogenous and exogenous testosterone in men. Prospective cohort studies with follow-up of ~5-15 years generally indicate no association or a possible inverse relationship between serum endogenous testosterone concentrations and composite major cardiovascular events, cardiovascular deaths and overall mortality. Pharmacoepidemiological studies of large databases generally show no association between testosterone therapy and incident major cardiovascular events, and some pharmacoepidemiological studies demonstrate an association with decreased overall mortality. Randomized, placebo-controlled trials indicate that there is no increased incidence of overall major cardiovascular events with 1-3 years of testosterone therapy. These placebo-controlled trials have major limitations including small numbers of participants, short duration of testosterone therapy and follow-up, and lack of systematic adjudication of cardiovascular events. Overall, the evidence indicates that endogenous testosterone concentrations and testosterone therapy at physiological dosages confer no or minimal effects on the incidence of cardiovascular outcomes. There is insufficient evidence to make conclusions about testosterone therapy for patients at high risk of cardiovascular events (e.g., men with recent myocardial infarctions or stroke and men with recurrent idiopathic deep venous thromboses). In general, clinicians should avoid prescribing supraphysiological testosterone therapy to hypogonadal men or men with slightly low to low-normal serum testosterone concentrations and no identified disorder of the hypothalamus-pituitary-testicular axis because of the uncertain cardiovascular risks and the lack of proven health benefits. For most men with bona fide hypogonadism, benefits of testosterone therapy exceed the potential risk of adverse cardiovascular effects.

Low Testosterone Level and Risk of Adverse Clinical Events among Male Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Cohort Studies

The phenomenon of low testosterone level is extremely common in male patients with chronic kidney diseases (CKDs). This meta-analysis aimed to evaluate whether the low circulating testosterone could independently predict adverse outcomes among male patients with chronic kidney diseases (CKDs). The data till May 2022 were systematically searched from Pubmed, Web of Science, and Embase from inception. Studies meeting the PICOS (population, intervention/exposure, control/comparison, outcomes, and study design) principles were included in this meta-analysis. Study-specific effect estimates were pooled using fixed-effects (I² > 50%) or random-effects models (I² < 50%). Ultimately, 9 cohort studies covering 5331 patients with CKDs were involved in this meta-analysis. The results suggested that per 1-standard deviation (SD) decrease in total testosterone independently increased the risk of all-cause mortality by 27% [hazard risk (HR) 1.27, 95% confidence interval (CI) 1.16–1.38], cardiovascular mortality by 100% (HR 2.00, 95% CI 1.39–2.86), cardiovascular events by 20% (HR 1.20, 95% CI 1.04–1.39), and infectious events by 41% (HR 1.41, 95% CI 1.08–1.84). Besides, with per 1-SD decrease in free testosterone, the risk of overall adverse events increased by 66% (HR 1.66, 95% CI 1.34–2.05). Stratified analyses indicated that the negative relationship of the total testosterone with all-cause death risk was independent of factors involving age, race, body mass index, diabetes, hypertension, C-reactive protein, creatinine, and sex hormone binding globulin. In conclusion, it was identified that low endogenous testosterone could serve as an independent predictor of adverse clinical events among male patients with CKDs.