Changes in BMI modulate age-associated changes in sex hormone binding globulin and total testosterone, but not bioavailable testosterone in young adult men: the CARDIA Male Hormone Study

Meta-analysis and construction of simple-to-use nomograms for approximating testosterone levels gained from weight loss in obese men

BACKGROUND

Obesity-induced hypogonadism, which manifests as erectile dysfunction and a lack of libido, is a less visible and under-recognized obesity-related disorder in men.

OBJECTIVE

We examined the impact of weight loss on total (TT) and free testosterone (FT) levels, and constructed nomograms to provide an easy-to-use visual aid for clinicians.

MATERIALS AND METHODS

Meta-analysis was conducted using RevMan (v5.3) and expressed in standardized mean differences (SMD) for testosterone. Parallel-scale nomograms were constructed from baseline and target body mass index values to estimate the gain in testosterone.

RESULTS

In total, 44 studies were included, comprising 1,774 participants and 2,159 datasets, as some studies included several datasets at different time points. Weight loss was controlled by low calorie diet (LCD) in 19 studies (735 participants, 988 datasets), by bariatric surgery (BS) in 26 studies (1,039 participants, 1,171 datasets), and by both in one study. The median follow-up was 26 weeks (interquartile range = 12-52). The range of baseline mean age was 21-68 yr, BMI: 26.2-71.2 kg/m2 , TT: 7-20.2 nmol/L and FT: 140-583 pmol/L. TT levels increased after weight loss by LCD: SMD (95%CI) = 2.5 nmol/L (1.9-3.1) and by BS: SMD = 7.2 nmol/L (6.0-8.4); the combined TT gain was 4.8 nmol/L (3.9-5.6). FT levels increased after weight reduction by LCD: SMD = 19.9 pmol/L (7.3-32.5) and by BS: SMD = 58.0 pmol/L (44.3-71.7); the combined gain was 42.2 pmol/L (31.4-52.9). Greater amounts of total and free testosterone could be gained by weight loss in men with higher baseline BMI, or lower levels of SHBG, TT and FT, while gain in TT was relatively greater in older and FT in younger age. Age-stratified nomograms revealed that compared to older men (> 40 yr), younger men (≤ 40 yr) gained less TT but more FT for a given weight loss.

DISCUSSION AND CONCLUSION

Both TT and FT levels increased after weight loss, relatively greater with higher baseline BMI, or lower levels of SHBG, TT and FT. Nomograms constructed from a large number of participants with a wide range of BMI and testosterone values provide an evidence-based and simple-to-use tool in clinical practice.

Examining the associations between testosterone and biomarkers as men age

OBJECTIVES

Testosterone concentrations in men decline with advancing age. However, the cause of the decline is yet to be fully elucidated. Therefore, the aims of this study were to examine the associations between chronic diseases such as obesity and type 2 diabetes mellitus (T2DM) with total testosterone (TT) and sex hormone-binding globulin (SHBG), using a large nationally-representative data set (National Health and Nutrition Examination Survey; NHANES).

METHODS

NHANES is a cross-sectional survey, physical examination, and laboratory evaluation of a nationally-representative sample of a non-institutionalized United States population. Male participants aged ≥18 years during the NHANES 2013-2014 and NHANES 2015-2016 survey periods were selected for this analysis. The analysis included the following data: body mass index (BMI), oral glucose tolerance test (OGTT), homeostatic model assessment of insulin resistance (HOMA-IR), insulin, glucose, and age.

RESULTS

An overweight or obese condition was significantly inversely associated with TT and SHBG, even after adjusting for other variables. Several variables associated with T2DM (OGTT, HOMA-IR, insulin, and glucose) were also inversely associated with TT; however, only the associations between OGTT and insulin with TT remained significant after adjusting for the other variables. Insulin and HOMA-IR levels were significantly inversely associated with SHBG; however, only the association between SHBG and pre-diabetic HOMA-IR levels remained significant after adjusting for the other variables. OGTT became significantly associated with SHBG after adjusting for the other variables. Age was significantly inversely associated with TT, but positively associated with SHBG, even after adjusting for other variables.

CONCLUSION

The results of the present study, which is the largest to date, indicate that a marker of obesity, BMI, and some markers of T2DM are both independently and significantly inversely associated with TT and SHBG.

A Novel Nomogram for Predicting Breast Cancer-specific Survival in Male Patients

OBJECTIVES

To compare breast cancer-specific survival (BCSS) of nonmetastatic invasive breast cancer between male (MBC) and female (FBC) patients, define clinicopathologic variables related to BCSS in nonmetastatic invasive MBC patients, and establish a nomogram for individual risk prediction.

MATERIALS AND METHODS

On the basis of Surveillance, Epidemiology, and End Results database, 2094 MBC and 48,104 FBC cases underwent propensity score matching (PSM). We compared the prognosis of patients before and after PSM and developed a nomogram for BCSS of nonmetastatic invasive MBC patients. Internal validation was performed using the consistency index, calibration curves, and receiver operating characteristic curves. Simultaneously, data from 49 nonmetastatic invasive MBC patients diagnosed between January 2012 and May 2016 were collected for external validation.

RESULTS

Before PSM, overall survival and BCSS were significantly shorter in MBC than those in FBC patients. After PSM, MBC patients continued to have a shorter overall survival, but not BCSS, than FBC patients. Marital status, age, histologic grade, estrogen/progesterone receptor status, Tumor Lymph Node stage, and surgery were included in the prediction model.

CONCLUSIONS

The nomogram developed in this study seems to be more accurate than conventional Tumor-nodal-metastasis staging staging to predict BCSS and may serve as an effective tool for assessing the prognosis of nonmetastatic invasive MBC.

The effect of long-term hypogonadism on body composition and morphometry of aged male Wistar rats

Clinical studies show that hypogonadism in the aging male is associated with obesity and osteoporosis. Experimental studies are mostly conducted on relatively young adult animals and the induced hypogonadism lasts for a relatively short time. The present study aimed to describe the effect of long-term hypogonadism beginning in puberty on body composition, morphometry, and bone mineral density in aged male rats. Morphometric measurements and dual-energy X-ray absorptiometry were conducted at the age of 30 months on control and gonadectomized males. Long-term hypogonadism did not affect body weight, but led to a higher fat mass (by 26 %), lower lean mass (by 44 %), shorter body length (by 9 %), and anogenital distance (by 26 %), as well as to lower tail circumference (by 15 %) in comparison to control males. Lower bone mineral density (by 13 %) and bone mineral content (by 15 %) were observed in gonadectomized males. Results showing sarcopenic obesity and osteoporosis in this model of long-term hypogonadism might mimic the situation in aging males better than the widely used short-term hypogonadism induced in young animals. The morphometric analysis could potentially be a useful tool to study normal weight obesity without the need for specific equipment.

Plasma sex hormone-binding globulin predicts neurodegeneration and clinical progression in prodromal Alzheimer's disease

It was unclear whether sex hormone-binding globulin (SHBG) was a circulating biomarker of Alzheimer’s disease (AD). We tested the cross-sectional relationships between plasma SHBG and cerebrospinal fluid (CSF) AD biomarkers in 707 non-demented adults. Next, the influences of plasma SHBG on dynamic changes of CSF Aβ42, hippocampus volume, brain metabolism, and cognition were explored in 448 non-demented adults from the Alzheimer’s disease Neuroimaging Initiative (ADNI). Finally, the predictive and diagnostic values of plasma SHBG in AD were explored. A positive correlation was found between SHBG levels in plasma and CSF. Individuals with higher plasma SHBG levels had lower CSF Aβ42 (p < 0.005), after adjusting for age, gender, education, APOE4 allele, and cognitive scores. Though no significant difference of plasma SHBG was observed between mild AD dementia and healthy normal, plasma SHBG could contribute to accelerated rates of CSF Aβ42 decrease (p < 0.0005), decline in brain metabolism (p < 0.05), and hippocampus atrophy (p < 0.01), cognitive decline (p < 0.01), as well as higher risk of AD dementia (p < 0.05). These findings indicated plasma SHBG could be a prodromal biomarker to predict disease progression in AD.

SHBG levels in primary infertile men: a critical interpretation in clinical practice

OBJECTIVE

We aimed to test the association between age, BMI and sex-hormone-binding globulin (SHBG) in a homogenous cohort of white-European men presenting for primary couple's infertility.

DESIGN

Retrospective study.

METHODS

Data from 1547 infertile men were analysed. Health-significant comorbidities were scored with the Charlson comorbidity index (CCI). Fasting serum hormones were measured in every patient. Age was considered according to quartile groups (<33, 33-41, >41 years) and BMI as normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2) and obesity (>30 kg/m2). Descriptive statistics and linear regression analysis tested the associations between age, BMI and SHBG.

RESULTS

Median SHBG levels increased across quartiles of age and decreased along with BMI increases (all P < 0.001). For each year increase in age, SHBG increased 0.32 nmol/L; conversely, for each unit increase in BMI, SHBG decreased by 1.1 nmol/L (all P < 0.001). SHBG levels decline with increasing BMI was greater than SHBG progressive increase with age. Overall, BMI explained 3.0 times more of the variability in SHBG than did ageing. At multivariate linear model, age and BMI were the most significant factors influencing SHBG concentration (all P < 0.001), after accounting for CCI, albumin levels and smoking status.

CONCLUSIONS

We found a wide distribution of SHBG concentrations across age and BMI values in primary infertile men. The association between BMI and lowered SHBG levels seems to be greater than the association of ageing with increased SHBG.

Sex Hormone-Binding Globulin Levels in Young Men Are Associated With Nonalcoholic Fatty Liver Disease in Midlife

INTRODUCTION

Cross-sectional data note lower levels of testosterone and sex hormone-binding globulin (SHBG) levels in men with nonalcoholic fatty liver disease (NAFLD). Whether sex hormone levels in young men are predictive of later risk of NAFLD is not known.

METHODS

Among men in the prospective population-based multicenter Coronary Artery Risk Development in Young Adults study (mean age 50; n = 837), we assessed whether testosterone and SHBG levels measured at study year 10 (median age 35 years) were associated with prevalent NAFLD at study year 25. NAFLD was defined using noncontrast abdominal computed tomography (CT) scan after excluding other causes of hepatic steatosis. The association of testosterone and SHBG with prevalent NAFLD was assessed by logistic regression.

RESULTS

Total testosterone levels in young men were inversely associated with subsequent prevalent NAFLD on unadjusted analysis (odds ratio [OR] 0.64, 95% confidence interval 0.53-0.7, P < 0.001), although no longer significant after adjustment for year 10 metabolic covariates as well as change in metabolic covariates from years 10 to 25 (OR 0.99, 95% confidence interval 0.76-1.27). In contrast, there was a significant inverse association of SHBG with prevalent NAFLD, independent of testosterone and metabolic covariates (OR 0.68, OR 0.51-0.92, P = 0.013). On formal mediation testing, visceral adiposity was found to explain ∼41.0% (95% confidence interval 27%-73%) of the association of lower SHBG with prevalent NAFLD.

CONCLUSIONS

Lower levels of SHBG in young men are associated with increase in prevalent NAFLD in middle age, independent of comprehensive metabolic risk factors. SHBG may provide a novel marker of NAFLD risk in young men.

Cross-Sectional Inverse Associations of Obesity and Fat Accumulation Indicators with Testosterone in Non-Diabetic Aging Men

Introduction/Objective: The aim of the study was to show which of the adipose tissue accumulation indicators correlate with testosterone disorders in non-diabetic aging men. Material and methods: 455 non diabetic men, recruited at primary care facilities, aged 50⁻75 participated in the study. The participants underwent anthropometric measurement and ELISA determination of total testosterone (TT), estradiol (E₂), dehydroepiandrosterone sulphate (DHEA-S), sex hormone binding protein (SHBG), and the determination of fasting glucose (FPG), high-density lipids cholesterol (HDL-Ch), and triacylglycerols (TAG) in serum. The following indicators were calculated: body mass index (BMI), waist-to-hip ratio (WHR), lipid accumulation product (LAP), and visceral adiposity index (VAI). Results: Men with testosterone deficiency syndrome (TDS) differed in each of the assessed obesity indices from those without TDS. All of the studied parameters correlated significantly negatively with TT concentration in blood serum, with VAI being the strongest predictor of TDS. It was shown that the threshold value at which the risk of TDS increased was 28.41 kg/m² for BMI, 1.58 for VAI, 104 cm for WC, and 37.01 for LAP. Conclusions: Indicators of fat accumulation that take into account biochemical parameters in assessing lipid metabolism are better markers of actual body fat deposition than indicators based solely on anthropometric measurements. Among them, VAI seems the most suitable biomarker of TDS in non-diabetic aging men.

The efficacy, bioavailability and safety of a novel hydroalcoholic testosterone gel 2% in hypogonadal men: results from phase II open-label studies

Pharmacokinetics, pharmacodynamics and safety of a novel hydroalcoholic testosterone gel 2% (TG) were evaluated in phase II sequential dose escalation studies using 3 application sites (thigh, abdomen and shoulder/upper arm) and 2 application methods. Hypogonadal men (n = 40), 18-75 years, with serum testosterone <300 ng dl(-1) were included in both studies. Study 1 evaluated hand-applied multiple doses of TG 1.25, 2.50 and 3.75 ml (23, 46 and 70 mg of testosterone, respectively), once daily for 10 days to shoulder/upper arm. Study 2 evaluated applicator-applied (TG 1.25, 2.50 and 3.75 ml) versus hand-applied (TG 2.5 ml) doses, once daily for 7 days to shoulder/upper arm. Primary endpoint for both studies was responder rate (Cave testosterone levels between 298 and 1050 ng dl(-1) ). In Study 1 following multiple applications, >70% participants in each group were responders. Dose-dependent increase was observed in PK values for total testosterone, free testosterone and DHT. In Study 2, responder rate was dose proportional: 16.7%, 50.0% and 77.8% responders in TG 1.25, 2.50 and 3.75 ml groups respectively. The bioavailability was highest for the shoulder application. There was a significant improvement in almost all the domains of sexual functioning. Applicator-application was preferred over hand-application by majority of the participants. TG was found to be safe and well tolerated in hypogonadal men.

Is Free Testosterone Concentration a Prognostic Factor of Survival in Chronic Renal Failure (CRF)?

Background

Lowered testosterone level in CRF patients is associated with elevated risk of death due to cardiovascular reasons, and is influenced by many factors, including acid-base balance disorders. Aims: evaluation of testosterone concentration (TT) and free testosterone concentration (fT) in pre-dialysis and dialysis patients; assessment of TT and fT relationships with biochemical parameters; evaluation of prognostic importance of TT and fT in predicting patient survival.

Material/Methods

4 groups of men: 14 – on hemodialysis (HD), 13 – on peritoneal dialysis (PD), 9 – with chronic renal failure (CRF) and 8 – healthy (CG), aged 56±17, 53±15, 68±12, 43±10 years, respectively. TT and biochemical parameters were measured; fT was calculated.

Results

The lowest TT and fT were observed in HD and CRF, the highest – in CG (p=0.035 for TT; p=0.007 for fT). fT in CRF and CG were different (p=0.031). TT and age was associated in HD (p=0.026). Age and fT was strongly associated in PD (p<0.001). After adjustment for age, TT was negatively associated with BMI (p=0.013) and fT was positively associated with HCO3 level (p=0.007). fT was lower in those who died during 5 years of observation than in survivors (p=0.009). We have found that, opposite to TT, fT appeared to be a better predictor of 5-year survival than age. After combining pH and HCO3 levels into a single variable – no acidosis, acidosis with HCO3 normal serum level, acidosis with low concentrations of HCO3 and adjustment for age and the study group – a trend toward the lowest values of free testosterone in decompensated acidosis was observed (p_trend=0.027). Such a trend was not seen for testosterone concentrations (p_trend=0.107).

Conclusions

Total and free testosterone levels were lower in HD and pre-dialysis than in healthy patients. Free testosterone level may predict long-term survival better than age. Total and free testosterone levels are lower in metabolic acidosis and total and free testosterone levels were positively associated with HCO3 level.

Association between serum total testosterone and Body Mass Index in middle aged healthy men

Objective:

To determine correlation of serum total testosterone with body mass index (BMI) and waist hip ratio (WHR) in healthy adult males.

Methods:

A cross sectional study was conducted on 200 nonsmoker healthy males (aged 30-50 years) university employees. They were selected by convenience sampling technique after a detailed medical history and clinical examination including BMI and Waist Hip Ratio (WHR) calculation. Blood sampling was carried out to measure serum total testosterone (TT) using facilities of Chemiluminescence assay (CLIA) technique in Dow Chemical Laboratory. Independent sample T test was used for mean comparisons of BMI and WHR in between low and normal testosterone groups. (Subjects having < 9.7 nmol/L of total testosterone in blood were placed in low testosterone group and subjects having ≥ 9.7 nmol/L of total testosterone in blood were placed in normal testosterone group). Correlation of testosterone with BMI and WHR was analyzed by Pearson Correlation.

Results:

Mean (± SD) age of the subjects included in this study was 38.7 (± 6.563) years mean (± SD) total testosterone was 15.92 (±6.322)nmol/L. The mean (± SD) BMI, and WHR were 24.95 (±3.828) kg/m² and 0.946 (±0.0474) respectively. Statistically significant differences were observed in the mean values of BMI and WHR for the two groups of testosterone. Significant inverse correlation of serum total testosterone with BMI(r = -0.311, p = 0.000) was recorded in this study. However testosterone was not significantly correlated with waist/hip ratio.(r = -0.126, p = 0.076)

Conclusion:

Middle age men working at DUHS who have low level of serum total testosterone are more obese than individuals with normal total testosterone level.

Association of testosterone levels with socio-demographic characteristics in a sample of Ugandan men

BACKGROUND

Testosterone, a male reproductive hormone, affects several physiological processes, such as sperm production, energy, strength, sexual behavior, sleep and the general well being of men. Normal levels of testosterone are necessary to effect these physiological processes. The objective of this study was to study the association between testosterone levels in a sample of Ugandan men with socio-demographic characteristics, and compare the testosterone levels of Ugandan men with that of men in other countries.

METHODS

Eighty men were enrolled from the medical campus at Makerere University. Blood samples were drawn from 7.00 - 8.00 a.m. and total testosterone was measured using radioimmunoassay. The free and bioavailable testosterone was calculated after measuring sex hormone binding globulin (SHBG) and albumin in the blood samples. Self-administered questionnaires were used to obtain socio-demographic characteristics of the subjects. Biometric measurements including weight, height and waist circumference were also recorded.

RESULTS

Serum testosterone levels of Ugandan men were within the normal physiological ranges. Married participants and those with dependents had lower testosterone than unmarried participants and those without dependents respectively. Sexually active participants had lower testosterone levels than those who were not sexually active.

CONCLUSION

Testosterone levels were lower in association with several socio-demographic characteristics including being married, having dependents, and daily coital frequency. Further research is warranted into the relationship between testosterone levels and contributory sexual behavior that may be important in understanding the spread of HIV/AIDS, given its high prevalence in sub-Saharan Africa.

"Linearity assessment methods for sex steroid hormones and carrier proteins among men in the National Health and Nutrition Examination Survey (NHANES III)"

INTRODUCTION

It has been hypothesized that racial disparities among several diseases are explained by differences in testosterone (T), 17-β estradiol (E), sex hormone binding globulin (SHBG) and albumin (A) levels, yet epidemiologic results have been mixed. Statistical advice regarding appropriate adjustment methods for carrier proteins of sex steroid hormones in the literature is scant. Therefore, we investigated different adjustment methods for carrier proteins.

METHODS

Data for 1496 men, >17 years from the Third National Health and Nutrition Examination Survey (NHANES III) 1988-91 were used to analyze linearity between sex hormones and carrier proteins by examining correlation, plots, and regression models. The statistical importance of age, body mass index (BMI), and race/ethnicity were examined for changes in results by the adjustment method.

RESULTS

T was weakly correlated with SHBG and A (r-squared, 0.25, 0.13, respectively) and E was weakly negatively correlated with A (p<0.0001), but not SHBG (p<0.1799). Based on the model residual plots and r-squared, the categorical model performed better than linear models. Regression coefficients for age, BMI, and race/ethnicity groups using quotient (e.g., T/A and E/A) models differed from continuous and categorical models.

CONCLUSION

Choosing an appropriate adjustment for carrier proteins is important to prevent bias in analyses and inconsistency in findings across studies. Linearity between variables should not be assumed when adjusting models, and should be conducted and reported. An independent categorical carrier protein variable is recommended in analysis exploring factors predicting sex hormone levels, although statistical testing should always be employed.

Anthropometric and hormonal risk factors for male breast cancer: male breast cancer pooling project results

BACKGROUND

The etiology of male breast cancer is poorly understood, partly because of its relative rarity. Although genetic factors are involved, less is known regarding the role of anthropometric and hormonally related risk factors.

METHODS

In the Male Breast Cancer Pooling Project, a consortium of 11 case-control and 10 cohort investigations involving 2405 case patients (n = 1190 from case-control and n = 1215 from cohort studies) and 52013 control subjects, individual participant data were harmonized and pooled. Unconditional logistic regression generated study design-specific (case-control/cohort) odds ratios (ORs) and 95% confidence intervals (CIs), with exposure estimates combined using fixed effects meta-analysis. All statistical tests were two-sided.

RESULTS

Risk was statistically significantly associated with weight (highest/lowest tertile: OR = 1.36; 95% CI = 1.18 to 1.57), height (OR = 1.18; 95% CI = 1.01 to 1.38), and body mass index (BMI; OR = 1.30; 95% CI = 1.12 to 1.51), with evidence that recent rather than distant BMI was the strongest predictor. Klinefelter syndrome (OR = 24.7; 95% CI = 8.94 to 68.4) and gynecomastia (OR = 9.78; 95% CI = 7.52 to 12.7) were also statistically significantly associated with risk, relations that were independent of BMI. Diabetes also emerged as an independent risk factor (OR = 1.19; 95% CI = 1.04 to 1.37). There were also suggestive relations with cryptorchidism (OR = 2.18; 95% CI = 0.96 to 4.94) and orchitis (OR = 1.43; 95% CI = 1.02 to 1.99). Although age at onset of puberty and histories of infertility were unrelated to risk, never having had children was statistically significantly related (OR = 1.29; 95% CI = 1.01 to 1.66). Among individuals diagnosed at older ages, a history of fractures was statistically significantly related (OR = 1.41; 95% CI = 1.07 to 1.86).

CONCLUSIONS

Consistent findings across case-control and cohort investigations, complemented by pooled analyses, indicated important roles for anthropometric and hormonal risk factors in the etiology of male breast cancer. Further investigation should focus on potential roles of endogenous hormones.

Association of prostate specific antigen concentration with lifestyle characteristics in Korean men

We investigated the relationships between demographics, lifestyle characteristics, and serum total prostate specific antigen (PSA) concentration and examined the population-based distribution of total PSA by age among 2,246 Korean men with a median age of 45 years. We obtained data about demographic and lifestyle characteristics based on self-reporting using a questionnaire. We also performed physical examinations, anthropometric measurements, and biochemical measurements. The PSA concentration increased with age and there was a significant difference in total PSA concentration between the age groups of 21-60 years and >60 years. Age>60 years, height≥1.8 m, a low frequency of alcohol consumption, and taking nutritional supplements showed a significantly increased odds ratio for increased PSA when 3.0 ng/ mL was chosen as the PSA cut-off level. Smoking status, BMI, percent body fat, diabetes mellitus, fatty liver, herbal medicine use, vitamin use, and diet were not significantly associated with total PSA regardless of the cut-off level. When interpreting a single PSA test, height, alcohol consumption, and nutritional supplement use should be considered, in addition to age.

Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study

OBJECTIVE

Health and lifestyle factors are associated with variations in serum testosterone levels in ageing men. However, it remains unclear how age-related changes in testosterone may be attenuated by lifestyle modifications. The objective was to investigate the longitudinal relationships between changes in health and lifestyle factors with changes in hormones of the reproductive endocrine axis in ageing men.

DESIGN

A longitudinal survey of 2736 community-dwelling men aged 40-79 years at baseline recruited from eight centres across Europe. Follow-up assessment occurred mean (±S.D.) 4.4±0.3 years later.

RESULTS

Paired testosterone results were available for 2395 men. Mean (±S.D.) annualised hormone changes were as follows: testosterone -0.1±0.95  nmol/l; free testosterone (FT) -3.83±16.8  pmol/l; sex hormone-binding globulin (SHBG) 0.56±2.5  nmol/l and LH 0.08±0.57  U/l. Weight loss was associated with a proportional increase, and weight gain a proportional decrease, in testosterone and SHBG. FT showed a curvilinear relationship to weight change; only those who gained or lost ≥15% of weight showed a significant change (in the same direction as testosterone). Smoking cessation was associated with a greater decline in testosterone than being a non-smoker, which was unrelated to weight change. Changes in number of comorbid conditions or physical activity were not associated with significant alterations in hypothalamic-pituitary-testicular (HPT) axis function.

CONCLUSIONS

Body weight and lifestyle factors influence HPT axis function in ageing. Weight loss was associated with a rise, and weight gain a fall, in testosterone, FT and SHBG. Weight management appears to be important in maintaining circulating testosterone in ageing men, and obesity-associated changes in HPT axis hormones are reversible following weight reduction.

Association of baseline sex hormone levels with baseline and longitudinal changes in waist-to-hip ratio: Multi-Ethnic Study of Atherosclerosis

Objective

Waist-to-hip ratio (WHR) is strongly associated with prevalent atherosclerosis. We analyzed the associations of baseline serum levels of testosterone (T), estradiol (E2), sex hormone binding globulin (SHBG), and dehydroepiandrosterone (DHEA) with WHR in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort.

Subjects

Baseline data was available for 3144 men and 2038 postmenopausal women, who were non-users of hormone therapy, who were 45–84 years of age, and of White, Chinese, Black or Hispanic racial/ethnic groups. Of these, 2708 men and 1678 women also had longitudinal measurements of WHR measured at the second and/or the third study visits (median follow-up 578 days, and 1135 days, respectively).

Results

In cross-sectional analyses adjusted for age, race, and cardiovascular disease risk factors, T was negatively associated with baseline WHR in men, while in both sexes, E2 was positively associated and SHBG was negatively associated with WHR (all p<0.001). In longitudinal analyses, further adjusted for follow-up time and baseline WHR, baseline T was negatively associated with WHR at follow-up (p=0.001) in men, while in both sexes, E2 was positively associated (p=0.004), and SHBG was negatively associated with WHR (p<0.001). The longitudinal association of E2, but not T, was independent of SHBG. In both cross-sectional or longitudinal analyses, there were no associations between DHEA and WHR in either men or women.

Conclusion

Sex hormones are associated with WHR at baseline and also during follow-up above and beyond their baseline association. Future research is needed to determine if manipulation of hormones is associated with changes in central obesity.

A cross-sectional study of the association of age, race and ethnicity, and body mass index with sex steroid hormone marker profiles among men in the National Health and Nutrition Examination Survey (NHANES III)

OBJECTIVES

Since sex hormone markers are metabolically linked, examining sex steroid hormones singly may account for inconsistent findings by age, race/ethnicity and body mass index (BMI) across studies. First, these markers were statistically combined into profiles to account for the metabolic relationship between markers. Then, the relationships between sex steroid hormone profiles and age, race/ethnicity and BMI were explored in multinomial logistic regression models.

DESIGN

Cross-sectional survey.

SETTING

The US Third National Health and Nutrition Examination Survey (NHANES III).

PARTICIPANTS

1538 Men, >17 years.

PRIMARY OUTCOME MEASURE

Sex hormone profiles.

RESULTS

Cluster analysis was used to identify four statistically determined profiles with Blom-transformed T, E, sex hormone binding globulin (SHBG), and 3-α diol G. We used these four profiles with multinomial logistic regression models to examine differences by race/ethnicity, age and BMI. Mexican American men >50 years were associated with the profile that had lowest T, E and 3-α diol G levels compared to other profiles (p<0.05). Non-Hispanic Black, overweight (25-29.9 kg/m(2)) and obese (>30 kg/m(2)) men were most likely to be associated with the cluster with the lowest SHBG (p<0.05).

CONCLUSION

The associations of sex steroid hormone profiles by race/ethnicity are novel, while the findings by age and BMI groups are largely consistent with observations from single hormone studies. Future studies should validate these hormone profile groups and investigate these profiles in relation to chronic diseases and certain cancers.

Trends in sex hormone concentrations in US males: 1988-1991 to 1999-2004

Previous studies suggest that male testosterone concentrations have declined over time. To explore this in a large US population, we examined testosterone and free testosterone concentrations in National Health and Nutrition Examination Surveys (NHANES) from 1988-1991 and 1999-2004. We also examined sex hormone-binding globulin (SHBG), estradiol, and androstanediol glucuronide (3α-diol-G) over the same period. Non-Hispanic white, non-Hispanic black, and Mexican-American men from 1988-1991 and 1999-2004 NHANES surveys who were ≥20 years old and had serum from morning blood draws were included in this analysis (1988-1991: N = 1,413; 1999-2004: N = 902). Testosterone, estradiol and SHBG were measured by competitive electrochemiluminescence immunoassays and 3α-diol-G was measured by enzyme immunoassay. Free testosterone was calculated using testosterone and SHBG values. Adjusted mean hormone concentrations were estimated using linear regression, accounting for NHANES sampling weights and design, age, race/ethnicity, body mass index, waist circumference, alcohol use and smoking. Differences in adjusted mean concentrations (Δ) and two-sided p-values were calculated; p < 0.05 was statistically significant. Overall, 3α-diol-G and estradiol declined between 1988-1991 and 1999-2004, but there was little change in testosterone, free testosterone, or SHBG (Δ: 3α-diol-G = -1.83 ng/mL, p < 0.01; estradiol = -6.07 pg/mL, p < 0.01; testosterone = -0.03 ng/mL, p = 0.75; free testosterone = -0.001 ng/mL, p = 0.67; SHBG = -1.17 nmol/L, p = 0.19). Stratification by age and race revealed that SHBG and 3α-diol-G declined among whites 20-44 years old (Δ: SHBG = -5.14 nmol/L, p < 0.01; 3α-diol-G = -2.89 ng/mL, p < 0.01) and free testosterone increased among blacks 20-44 years old (Δ: 0.014 ng/mL, p = 0.03). Estradiol declined among all ages of whites and Mexican-Americans. In conclusion, there was no evidence for testosterone decline between 1988-1991 and 1999-2004 in the US general population. Subgroup analyses suggest that SHBG and 3α-diol-G declined in young white men, estradiol declined in white and Mexican-American men, and free testosterone increased in young black men. These changes may be related to the increasing prevalence of reproductive disorders in young men.

The prevalence of low sex steroid hormone concentrations in men in the Third National Health and Nutrition Examination Survey (NHANES III)

BACKGROUND

Physiologic processes during ageing leading to multi-morbidity and diseases that increase risk of premature death may be influenced by ageing-associated changes in endogenous hormone production.

OBJECTIVE

To evaluate the decline in sex steroid hormone levels across age and estimate the number of US men 40+ years old who may have low hormone levels.

DESIGN

We measured serum testosterone, oestradiol and sex hormone binding globulin by immunoassay in 1351 men 20+ years old in Third National Health and Nutrition Examination Survey. We estimated free hormones by mass action.

RESULTS

Free testosterone declined most rapidly with age (a 2% decline in geometric mean concentration occurred after ageing 1·3 years), followed by total testosterone (2·4 years), free oestradiol (4·1 years) and total oestradiol (8·1 years). These hormone changes with age translated into 25·0% and 30·2% of men 70+ years old having low total (which we defined as <10·4 nm) and free (<0·17 nm) testosterone, respectively, and 8·3% and 23·9% having low total (<73·4 pm) and free (<2·2 pm) oestradiol. Using population size projections between the 2000 and 2010 Censuses, we estimated that 8·4 (95% CI 4·7-12·2), 6·2 (3·1-9·2) and 6·0 (3·1-9·0) million men 40+ years old may have low total testosterone, free testosterone and free oestradiol, respectively. The prevalences were only modestly lower in men without prevalent chronic diseases.

CONCLUSION

Although no consensus exists for defining low hormone levels in ageing men, a substantial number of US men may have low sex steroid hormone levels, possibly putting them at risk for adverse health consequences and premature death.

Obesity and prostate cancer detection: insights from three national surveys

BACKGROUND

Previous studies suggest that obesity is associated with higher prostate cancer progression and mortality despite an association with lower prostate cancer incidence. This study aims to better understand these apparently inconsistent relationships among obese men by combining evidence from 3 nationally representative cross-sectional surveys.

METHODS

We evaluated relationships between obesity and 1) testosterone concentrations in the Third National Health and Nutrition Examination Survey (NHANES III; n=845); 2) prostate-specific antigen (PSA) in NHANES 2001-2004 (n=2458); and 3) prostate biopsy rates in the National Health Interview Survey (NHIS 2000; n=4789) population. Mean testosterone, PSA concentrations, and biopsy rates were computed for Body Mass Index (BMI) categories.

RESULTS

Testosterone concentrations were inversely associated with obesity (P-trend <.0001) in NHANES III. In NHANES 2001-2004, obese (BMI >35) versus lean (BMI <25) men were less likely to have PSA concentrations that reached the biopsy threshold of >4 ng/mL (3% vs 8%; P <.0001). Among NHIS participants, all BMI groups had similar rates of PSA testing (P=.24). However, among men who had PSA tests, 11% of men with BMI >30 versus 16% with BMI <25, achieved a PSA threshold of 4 ng/mL; P=.01. Furthermore, biopsy rates were lower among men with BMI >30 versus BMI <25 in NHIS participants (4.6% vs 5.8%; P=.05).

CONCLUSIONS

Obesity was associated with lower PSA-driven biopsy rates. These data support further studies to test the hypothesis that obesity affects prostate cancer detection independent of prostate cancer risk by decreasing the PSA-driven biopsy rates.

Sex hormone-binding globulin: a new marker of disease severity and prognosis in men with chronic heart failure

INTRODUCTION AND OBJECTIVES

Sex hormone-binding globulin (SHBG) is a key regulator of the actions of anabolic steroids. Chronic heart failure (HF) has been associated with anabolic steroid deficiency, but its relationship with SHBG is not known.

METHODS

The study involved 104 men (53+/-11 years) with HF (i.e. left ventricular ejection fraction [LVEF] <40%) attending a specialist clinic on optimum treatment and in a stable condition. At enrolment, the median and interquartile range (IQR) SHBG level was determined, associated hormone levels were measured, and known risk factors were recorded. The study end-point was cardiac death within 3 years.

RESULTS

At enrolment, the SHBG level (median 34.5 nmol/L, IQR 27-50 nmol/L) was correlated with the N-terminal probrain natriuretic peptide level (r=0.271, P=.005), LVEF (r=-0.263, P=.007), body mass index (r=-0.199, P=.020) and total testosterone level (r=0.332, P=.001). The median SHBG level was higher in the 16 patients (15.4%) who died, at 48.5 nmol/L (IQR 36-69.5 nmol/L) vs. 33 nmol/L (IQR 25.3-48.7 nmol/L; P=.001), and a high level was associated with an increased risk of death (hazard ratio [HR]=1.045, 95% confidence interval [CI] 1.021-1.069; P< .001). The association remained significant after adjustment in Cox multivariate regression modeling, at HR=1.049 (95% CI 1.020-1.079; P=.001). Analysis by SHBG tertiles showed mortality was 30% in the third tertile, 14% in the second, and 4% in the first (log rank 0.007; HR=3.25, 95% CI 1.43-7.34; P=.004).

CONCLUSIONS

The SHBG level correlated with measures of HF severity and was associated with a higher risk of cardiac death. Further studies are needed to clarify whether SHBG plays a role in HF pathophysiology.

Circulating steroid hormones in prostate carcinogenesis. Part 1 – Androgens

The aim of this review is to identify circulating steroids associated with prostate cancer (PCa) in bibliographic reports. First, we summarize chronological reports comparing circulating steroid levels in men with a high risk of PCa, such as African-Americans (AAs), with men having a lower risk. Higher testosterone plasma levels in young AA men have been reported. However, the difference between AAs and Caucasians decreases with age. When measured, dihydrotestosterone (DHT) was found to be higher in AAs; however, these results must be taken with caution, as immunological assay of this steroid is difficult. Second, we summarize chronological reports concerning circulating steroids assayed in blood samples drawn several years before a diagnosis of PCa was made, compared to controls. These nested case-control studies did not lead to straightforward conclusions regarding an increase in circulating testosterone. However, large collaborative studies showed a trend of a decrease in plasma sex hormone binding globulin, consequently an increase in bioavailable plasma testosterone in PCa. These nested case-control studies failed to associate plasma DHT levels with PCa risk. Third, we summarize numerous chronological publications relating plasma concentrations, measured at the time of PCa diagnosis. Numerous results showed a decrease in plasma testosterone levels in aggressive PCa (high Gleason score, advanced stage with positive surgical margins). Testosterone levels returned to normal several months after prostatectomy. All plasma hormone assay levels were always carried out using immunological methods. We recommend replacing this methodology by mass spectrometry coupled with gas chromatography or liquid chromatography in these epidemiologic studies.

Androgen and prostate cancer: is the hypothesis dead?

Data from animal, clinical, and prevention studies support the role of androgen in prostate cancer growth, proliferation, and progression. However, results serum-based epidemiologic studies in humans have been inconclusive. Part of the inconsistency in these findings stems from differences in study population, assay accuracy, intraperson variation, and limited sample size. Recently, data from a large pooled analysis of 18 prospective studies (3,886 cases and 6,438 healthy controls) showed no association between serum androgen and prostate cancer risk. It is not surprising that the pooled analysis did not find a positive link between circulating levels of total testosterone and prostate cancer risk because, individually, few of the 18 studies included in the pooled analysis reported a substantial positive association. The null result, however, does not pronounce a death sentence for the androgen hypothesis; rather, it underscores the importance of a better understanding of androgen action within the prostate, including the relationship between tissue and serum levels of androgen. In this commentary, we explain why circulating levels of testosterone may not reflect androgen action in the prostate and why tissue levels of androgen, in particular dihydrotestosterone, and the androgen receptor and its coregulators are critical to androgen action in the prostate and should be incorporated in future studies. It is timely to integrate system thinking into our research and use an interdisciplinary approach that involves different disciplines, including epidemiology, endocrinology, pathology, and molecular biology, to help dissect the complex interplay between sex steroids and genetic and lifestyle factors in prostate cancer etiology.

Associations of lifestyle and physiologic factors with prostate-specific antigen concentrations: evidence from the National Health and Nutrition Examination Survey (2001-2004)

Studies suggest inverse associations between obesity and prostate-specific antigen (PSA). However, there is little evidence whether factors related to obesity, including lifestyle (diet and physical activity) and physiologic factors (insulin resistance and metabolic syndrome), influence PSA. We used dietary, physical activity, and serum PSA, insulin, glucose, and lipid data for men >40 years from the National Health and Nutrition Examination Survey (2001-2004; N = 2,548). Energy, fat, and carbohydrate intakes were estimated from a 24-hour dietary recall. Men were considered as having metabolic syndrome based on the Adult Treatment Panel III criteria. Leisure-time physical activity and doctor-diagnosed hypertension were self-reported. Body mass index was calculated from measured weight and height. We computed the geometric mean PSA (ng/mL), adjusted for age, race, and body mass index, by tertile of energy, fat, and carbohydrate intake and level of physical activity, and among men with and without insulin resistance and metabolic syndrome in the whole population and by race. The geometric mean PSA (95% confidence interval) among men in the lowest tertile of energy was 1.05 (0.97-1.1) relative to 0.85 (0.8-0.9) in the highest tertile (P = 0.0002) in the whole population. The PSA concentrations were lower among overweight men with higher versus lower energy intake (P = 0.001). The PSA concentrations in men with insulin resistance was lower [0.87 (0.8-0.9)] relative to men without insulin resistance [0.98 (0.9-1.1)] at P = 0.04. All associations were in similar directions within racial subgroups. No associations were observed between the other lifestyle and physiologic factors. Additional studies are required to confirm these results and to investigate the potential mechanisms that may explain these relationships.

Hypogonadotropic hypogonadism in a patient with morbid obesity

Obesity has recently become one of the most important public health problems. It is associated with a high rate of mortality, mainly because of cardiovascular disease, and can cause hormonal abnormalities such as hypogonadotropic hypogonadism. Weight loss is very beneficial for obese patients, because it results in improvement or even normalization of these conditions. In this report, we describe a morbidly obese patient with hypogonadotropic hypogonadism, which was probably caused by hyperprolactinemia and exacerbated by obesity-induced hormonal imbalances. After medical treatment for hyperprolactinemia and bariatric surgery, the patient's hormonal status became normal. Although morbid obesity can cause hypogonadotropic hypogonadism in men, the differential diagnosis should include other potential causes of hypogonadism if free testosterone levels are below normal.

Obesity, metabolic syndrome, and prostate cancer

Although obesity has been consistently linked to an increased risk of several malignancies, including cancers of the colon, gallbladder, kidney, and pancreas, its role in prostate cancer etiology remains elusive. Data on the association between obesity and prostate cancer incidence are inconsistent, and in some studies obesity is associated with an increase in risk of high-grade prostate cancer but with a decrease in risk of low-grade tumors. In contrast, obesity has been consistently associated with an increased risk of prostate cancer aggressiveness and mortality. The differential effects of obesity on subtypes of prostate cancer suggest etiologic heterogeneity in these tumors and complex interactions between androgen metabolism and several putative risk factors, including insulin resistance, diabetes, inflammation, and genetic susceptibility, on prostate cancer risk. Data on the role of abdominal obesity, insulin resistance, and metabolic syndrome in prostate cancer etiology are limited. Obesity has been shown to be associated with a state of low-grade chronic inflammation, and insulin resistance and the metabolic syndrome are associated with adverse metabolic profiles and with higher circulating concentrations of inflammation-related markers, including leptin, interleukin-6, and tumor necrosis factor-, many of which have been shown to enhance tumor growth. Thus, whether obesity and metabolic syndrome modulate the risk of prostate cancer through chronic inflammation needs to be investigated further. Given that the prevalence of obesity and metabolic syndrome is increasing worldwide and that the world population is aging, the roles of obesity and metabolic syndrome in prostate carcinogenesis warrant further clarification.

Associations of androgens with physical activity and fitness in young black and white men: the CARDIA Male Hormone Study

OBJECTIVE

The association between physical activity or cardiovascular fitness and chronic disease risk in men might be mediated, in part, through androgens. Limited data exists on the potential associations of activity or fitness with serum hormones. We examined the associations of serum testosterone and sex hormone binding globulin (SHBG) concentrations with physical activity and cardiorespiratory fitness in black and white young men.

METHOD

Data were collected from 391 black and 604 white male participants of the Coronary Artery Risk Development in (Young) Adults (CARDIA) Male Hormone Study aged 24-32 in 1992-1993. Cross-sectional associations of serum total testosterone (TT), bioavailable testosterone (BT) and SHBG levels with self-reported total physical activity score, and in a subset of men (n=617) with cardiorespiratory fitness measured via duration on a treadmill test were assessed. Five-year longitudinal associations of change in hormones with changes in physical activity also were examined.

RESULTS

There were no cross-sectional or longitudinal associations of physical activity with SHBG, TT or BT in either black or white men. Fitness was positively associated with SHBG only in white men, but was not associated with TT or BT in either group.

CONCLUSION

Overall the results do not support an association of self-reported physical activity with androgens, whereas they do suggest that fitness might be associated with SHBG in white men.

The Clinical Biochemistry of Obesity—More Than Skin Deep

While obesity has a high prevalence in developed countries, the routine abnormalities seen from the clinical biochemistry laboratory that may be caused by obesity related pathology do not seem to be as common. Insulin resistance, which is often associated with obesity, is difficult to assess as formal procedures are too complex for clinical practice. Furthermore the interpretation of insulin levels is hampered by their in vivo variability, assay differences and the lack of reference intervals from an unaffected reference population. Interpretation of fasting glucose levels between 5.5 and 6.0mmol/L are also being debated however, it is useful to understand the age related changes in this parameter, which may also be due to increasing obesity in the reference population. The association of obesity and dyslipidaemia in the metabolic syndrome should focus on elevated triglycerides (>1.5mmol/L), which is associated with low HDLC and correlates with atherogenic small dense LDL. High triglycerides are also predictive of fatty liver and the common abnormality of an elevated ALT may not be appreciated if laboratories allow their reference intervals to increase as the population gets more obese with aging. SHBG levels fall with insulin resistance/hyperinsulinaemia and this needs to be taken into account when testosterone is measured. However, low SHBG is showing huge potential as a disease and prognostic marker in obesity. These commonly available tests provide useful insights for the obese patient and their utility may improve with future research into the growing problem of obesity.