Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys

Influence of marital status on testosterone levels-A ten year follow-up of 1113 men

Based on a large population of 1113 men aged 30-60 at baseline (mean: 44.1 years, standard deviation: 10.5), we investigated whether intra-individual changes in testosterone (T) and related reproductive hormones during a ten year period were dependent of marital status at baseline and follow-up. The studied men were part of a health survey in Denmark, conducted between 1982 and 1984 with a follow-up examination approximately ten years later. Data on reproductive hormones, measured in serum, and lifestyle and marital status were obtained at both time points. As expected, an age-related decline in testosterone was observed. However, independent of age and lifestyle, we observed that men who went from unmarried to married (n=81) during the study period experienced an accelerated age-related decline in testosterone (-6.6nmol/L) whereas men who went from married to unmarried (n=67) experienced an attenuated age-related decline (-2.3nmol/L). Men who were either married or unmarried at both time points (n=167, n=798, respectively) had a testosterone decline in between (-3.7nmol/L and -4.6nmol/L, respectively). Changes in T/LH ratio did not differ according to marital status indicating that the lowered T level is not compensated by increasing LH levels. This could suggest a modification of the gonadostat due to an adaptation to changing life circumstances.

Causal relationship between obesity and serum testosterone status in men: A bi-directional mendelian randomization analysis

CONTEXT

Obesity in men is associated with low serum testosterone and both are associated with several diseases and increased mortality.

OBJECTIVES

Examine the direction and causality of the relationship between body mass index (BMI) and serum testosterone.

DESIGN

Bi-directional Mendelian randomization (MR) analysis on prospective cohorts.

SETTING

Five cohorts from Denmark, Germany and Sweden (Inter99, SHIP, SHIP Trend, GOOD and MrOS Sweden).

PARTICIPANTS

7446 Caucasian men, genotyped for 97 BMI-associated SNPs and three testosterone-associated SNPs.

MAIN OUTCOME MEASURES

BMI and serum testosterone adjusted for age, smoking, time of blood sampling and site.

RESULTS

1 SD genetically instrumented increase in BMI was associated with a 0.25 SD decrease in serum testosterone (IV ratio: -0.25, 95% CI: -0.42--0.09, p = 2.8*10-3). For a body weight reduction altering the BMI from 30 to 25 kg/m2, the effect would equal a 13% increase in serum testosterone. No association was seen for genetically instrumented testosterone with BMI, a finding that was confirmed using large-scale data from the GIANT consortium (n = 104349).

CONCLUSIONS

Our results suggest that there is a causal effect of BMI on serum testosterone in men. Population level interventions to reduce BMI are expected to increase serum testosterone in men.

Vitamin D treatment improves levels of sexual hormones, metabolic parameters and erectile function in middle-aged vitamin D deficient men

BACKGROUND

The associations between serum vitamin D (VD), serum testosterone (TT) and metabolic syndrome are complex and with limited published research, particularly on the effects of VD treatment on sexual hormones, erectile function and the metabolic syndrome.

OBJECTIVES

This study assessed whether a monthly high dose VD treatment for 12 months in VD deficient middle-aged men was associated with: changes in levels of sexual hormones, improvement of diabetes control and metabolic syndrome components, better erectile function [International Index of Erectile Function (IIEF)-5 questionnaire]; and changes in a prostate marker.

MATERIALS AND METHODS

Descriptive research of a prospective study, conducted between October 2014 and September 2015, 102 male patients ≥35 [(±SD: 53.2 ± 10.5), (range 35-64)] years with deficient serum VD level (<30 ng/mL) were included in the study. Participants were followed up for one year, with monitoring at 3-, 6-, 9- and 12-months. At the initial baseline visit, a complete medical examination was conducted, and blood was drawn for laboratory tests for above biochemical and hormonal variables under examination. Participants received an initial VD (Ergocalciferol; oral solution 600 000 IU/1.5 ml), and followed a VD treatment regime thereafter. At the four follow up visits (3, 6, 9 and 12 months), blood was collected, and patients' erectile function was evaluated by IIEF-5 questionnaire.

MAIN OUTCOME MEASURES

During the follow up visits, all the biochemical and hormonal (TT, estradiol and luteinizing hormones, HbA1c, serum lipids profile) were assessed, and patients' erectile function was evaluated by IIEF-5 questionnaire.

RESULTS

Patients' mean age was 53.2 ± 10.4 years. Serum VD exhibited significant increments (p <0.001) from baseline (15.16 ± 4.64 ng/mL), to 3 (31.90 ± 15.99 ng/mL), 6 (37.23 ± 12.42 ng/mL), 9 (44.88 ± 14.49 ng/mL) and 12 months (48.54 ± 11.62 ng/mL), and there was significant stepladder increases in both serum TT level (12.46 ± 3.30 to 15.99 ± 1.84 nmol/L) and erectile function scores (13.88 ± 3.96 to 20.25 ± 3.24) (p <0.001 for both). We also observed significant stepladder decreases in estradiol (87.90 ± 27.16 to 69.85 ± 14.80 pmol/L, p = 0.001), PTH (from 58.52 ± 28.99 to 38.33 ± 19.44 pg/mL, p <0.001) and HbA1c levels (7.41 ± 2.85 to 6.66 ± 1.67%, p = 0.001). Mean BMI significantly decreased from 33.91 ± 6.67 to 33.14 ± 6.35 kg/m² (p = 0.001); and PSA values significantly increased from 0.59 ± 0.30 to 0.82 ± 0.39 ng/mL (p <0.001) at the end of the 12 months' follow-up. There were no changes in LH levels.

CONCLUSION

This study demonstrated that VD treatment improves testosterone levels, metabolic syndrome and erectile function in middle-aged men. More randomized placebo-controlled interventional trials of VD treatment in patients with the metabolic syndrome and low TT could assist in uncovering the putative roles of VD.

Fatty acid intake in relation to reproductive hormones and testicular volume among young healthy men

Emerging evidence suggests that dietary fats may influence testicular function. However, most of the published literature on this field has used semen quality parameters as the only proxy for testicular function. We examined the association of fat intake with circulating reproductive hormone levels and testicular volume among healthy young Spanish men. This is a cross-sectional study among 209 healthy male volunteers conducted between October 2010 and November 2011 in Murcia Region of Spain. Participants completed questionnaires on lifestyle, diet, and smoking, and each underwent a physical examination, and provided a blood sample. Linear regression was used to examine the association between each fatty acid type and reproductive hormone levels and testicular volumes. Monounsaturated fatty acids intake was inversely associated with serum blood levels of calculated free testosterone, total testosterone, and inhibin B. A positive association was observed between the intake of polyunsaturated fatty acids, particularly of omega-6 polyunsaturated fatty acids, and luteinizing hormone concentrations. In addition, the intake of trans fatty acids was associated with lower total testosterone and calculated free testosterone concentrations (P trend = 0.01 and 0.02, respectively). The intake of omega-3 polyunsaturated fatty acids was positively related to testicular volume while the intake of omega-6 polyunsaturated fatty acids and trans fatty acids was inversely related to testicular volume. These data suggest that fat intake, and particularly intake of omega 3, omega 6, and trans fatty acids, may influence testicular function.

Self-reported mobile phone use and semen parameters among men from a fertility clinic

There is increasing concern that use of mobile phones, a source of low-level radio-frequency electromagnetic fields, may be associated with poor semen quality, but the epidemiologic evidence is limited and conflicting. The relationship between mobile phone use patterns and markers of semen quality was explored in a longitudinal cohort study of 153 men that attended an academic fertility clinic in Boston, Massachusetts. Information on mobile phone use duration, headset or earpiece use, and the body location in which the mobile phone was carried was ascertained via nurse-administered questionnaire. Semen samples (n=350) were collected and analyzed onsite. To account for multiple semen samples per man, linear mixed models with random intercepts were used to investigate the association between mobile phone use and semen parameters. Overall, there was no evidence for a relationship between mobile phone use and semen quality.

Disruption of steroidogenesis: Cell models for mechanistic investigations and as screening tools

In the modern world, humans are exposed during their whole life to a large number of synthetic chemicals. Some of these chemicals have the potential to disrupt endocrine functions and contribute to the development and/or progression of major diseases. Every year approximately 1000 novel chemicals, used in industrial production, agriculture, consumer products or as pharmaceuticals, are reaching the market, often with limited safety assessment regarding potential endocrine activities. Steroids are essential endocrine hormones, and the importance of the steroidogenesis pathway as a target for endocrine disrupting chemicals (EDCs) has been recognized by leading scientists and authorities. Cell lines have a prominent role in the initial stages of toxicity assessment, i.e. for mechanistic investigations and for the medium to high throughput analysis of chemicals for potential steroidogenesis disrupting activities. Nevertheless, the users have to be aware of the limitations of the existing cell models in order to apply them properly, and there is a great demand for improved cell-based testing systems and protocols. This review intends to provide an overview of the available cell lines for studying effects of chemicals on gonadal and adrenal steroidogenesis, their use and limitations, as well as the need for future improvements of cell-based testing systems and protocols.

Semen phthalate metabolites, semen quality parameters and serum reproductive hormones: A cross-sectional study in China

Exposure to phthalates has been found to have adverse effects on male reproductive function in animals. However, the findings from human studies are inconsistent. Here we examined the associations of phthalate exposure with semen quality and reproductive hormones in a Chinese population using phthalate metabolite concentrations measured in semen as biomarkers. Semen (n = 687) and blood samples (n = 342) were collected from the male partners of sub-fertile couples who presented to the Reproductive Center of Tongji Hospital in Wuhan, China. Semen quality parameters and serum reproductive hormone levels were determined. Semen concentrations of 8 phthalate metabolites were assessed using high-performance liquid chromatography and tandem mass spectrometry. Associations of the semen phthalate metabolites with semen quality parameters and serum reproductive hormones were assessed using confounder-adjusted linear and logistic regression models. Semen phthalate metabolites were significantly associated with decreases in semen volume [mono-n-butyl phthalate (MBP), mono-(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP)], sperm curvilinear velocity [monobenzyl phthalate (MBzP), MEHP, the percentage of di-(2-ethylhexyl)-phthalate metabolites excreted as MEHP (%MEHP)], and straight-line velocity (MBzP, MEHP, %MEHP), and also associated with an increased percentage of abnormal heads and tails (MBzP) (all p for trend <0.05). These associations remained suggestive or significant after adjustment for multiple testing. There were no significant associations between semen phthalate metabolites and serum reproductive hormones. Our findings suggest that environmental exposure to phthalates may impair human semen quality.

Bioavailable Testosterone Linearly Declines Over A Wide Age Spectrum in Men and Women From The Baltimore Longitudinal Study of Aging

BACKGROUND

Age-related changes in testosterone levels in older persons and especially in women have not been fully explored. The objective of this study was to describe age-related trajectories of total testosterone (TT), ammonium sulfate precipitation-measured bioavailable testosterone (mBT), and sex hormone-binding glycoprotein (SHBG) in men and women from the Baltimore Longitudinal Study of Aging, with special focus on the oldest adults.

METHODS

Participants included 788 White men and women aged 30-96 years with excellent representation of old and oldest old, who reported not taking medications known to interfere with testosterone. Longitudinal data were included when available. TT, mBT, and SHBG were assayed. Age-related trajectories of mBT were compared with those obtained using calculated bioavailable testosterone (cBT). Generalized least square models were performed to describe age-related trajectories of TT, mBT, and SHBG in men and women.

RESULTS

mBT linearly declines over the life span and even at older ages in both sexes. In men, TT remains quite stable until the age of 70 years and then declines at older ages, whereas in women TT progressively declines in premenopausal years and slightly increases at older ages. Differences in age-related trajectories between total and bioavailable testosterone are only partially explained by age changes in SHBG, whose levels increases at accelerated rates in old persons. Noteworthy, although mBT and cBT highly correlated with one another, mBT is a much stronger correlate of chronological age than cBT.

CONCLUSION

In both men and women, mBT linearly declines over the life span and even at old ages. Its relationship with age-related phenotypes should be further investigated.

Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility

It is predicted that Japan and European Union will soon experience appreciable decreases in their populations due to persistently low total fertility rates (TFR) below replacement level (2.1 child per woman). In the United States, where TFR has also declined, there are ethnic differences. Caucasians have rates below replacement, while TFRs among African-Americans and Hispanics are higher. We review possible links between TFR and trends in a range of male reproductive problems, including testicular cancer, disorders of sex development, cryptorchidism, hypospadias, low testosterone levels, poor semen quality, childlessness, changed sex ratio, and increasing demand for assisted reproductive techniques. We present evidence that several adult male reproductive problems arise in utero and are signs of testicular dysgenesis syndrome (TDS). Although TDS might result from genetic mutations, recent evidence suggests that it most often is related to environmental exposures of the fetal testis. However, environmental factors can also affect the adult endocrine system. Based on our review of genetic and environmental factors, we conclude that environmental exposures arising from modern lifestyle, rather than genetics, are the most important factors in the observed trends. These environmental factors might act either directly or via epigenetic mechanisms. In the latter case, the effects of exposures might have an impact for several generations post-exposure. In conclusion, there is an urgent need to prioritize research in reproductive physiology and pathophysiology, particularly in highly industrialized countries facing decreasing populations. We highlight a number of topics that need attention by researchers in human physiology, pathophysiology, environmental health sciences, and demography.

Reference ranges of 17-hydroxyprogesterone, DHEA, DHEAS, androstenedione, total and free testosterone determined by TurboFlow-LC-MS/MS and associations to health markers in 304 men

We report reference ranges based on LC-MS/MS for testosterone (T), free testosterone (FT) and its precursors, i.e. 17-hydroxyprogesterone (17-OHP), dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEAS) and androstenedione (Adione), in relation to different health markers and lifestyle factors. The study was based on 304 healthy men aged 30-61 years participating in a population-based cross-sectional study (Health2008). Examination program consisted of a clinical examination, completion of a self-administered questionnaire and blood sampling. Steroid metabolites were measured by a validated and sensitive LC-MS/MS method. Older age-groups were significantly associated with decreased concentrations of DHEA, DHEAS, Adione, and FT, while no significant associations with age were shown for 17-OHP or T. Participants with BMI≥30 kg/m(2) had lower age-related steroid metabolite z-scores compared to participants with BMI<30 kg/m(2), i.e. 17-OHP: -0.51 vs. 0.08 (p<0.001); DHEA: -0.27 vs. 0.09 (p=0.014); Adione: -0.29 vs. 0.09 (p=0.012); T: -0.99 vs. 0.14 (p<0.001); and FT -0.55 vs. 0.05 (p<0.001), respectively. In conclusion, this large study on serum steroid metabolites and concomitant assessment of health markers in healthy men provides age-related reference ranges, and furthermore evaluates the impact of lifestyle factors and metabolic syndrome on androgen metabolite levels.

The Association of Reproductive Hormone Levels and All-Cause, Cancer, and Cardiovascular Disease Mortality in Men

CONTEXT

Testosterone (T) levels have been associated with mortality, but controversy exists.

OBJECTIVE

Our objective was to investigate associations between serum levels of total T, SHBG, free T, estradiol, LH and FSH, and subsequent mortality with up to 30 years of follow-up.

DESIGN

This was a prospective cohort study consisting of men participating in four independent population-based surveys (MONICA I-III and Inter99) from 1982 to 2001 and followed until December 2012 with complete registry follow-up.

SETTING AND PARTICIPANTS

A total of 5350 randomly selected men from the general population aged 30, 40, 50, 60, or 70 years at baseline participated.

MAIN OUTCOMES AND MEASURES

All-cause mortality, cardiovascular disease (CVD) mortality, and cancer mortality were the main outcomes.

RESULTS

A total of 1533 men died during the follow-up period; 428 from CVD and 480 from cancer. Cox proportional hazard models revealed that men in highest LH quartile had an increased all-cause mortality compared to lowest quartile (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.14-1.53). Likewise, increased quartiles of LH/T and estradiol increased the risk of all-cause mortality (HR, 1.23; 95% CI, 1.06-1.43; HR, 1.23; 95% CI 1.06-1.43). No association to T levels was found. Higher LH levels were associated with increased cancer mortality (HR, 1.42; 95% CI, 1.10-1.84) independently of smoking status. Lower CVD mortality was seen for men with T in the highest quartile compared to lowest (HR, 0.72; 95% CI, 0.53-0.98). Furthermore, negative trends were seen for SHBG and free T in relation to CVD mortality, however insignificant.

CONCLUSION

The observed positive association of LH and LH/T, but not T, with all-cause mortality suggests that a compensated impaired Leydig cell function may be a risk factor for death by all causes in men. Our findings underpin the clinical importance of including LH measurement in the diagnostic work-up of male patients seeking help for possible androgen insufficiency.

Age-specific population centiles for androgen status in men

AIM

The age-specific population profiles in men of circulating testosterone and its two bioactive metabolites dihydrotestosterone (DHT) and estradiol (E2) across the adult lifespan and its determinants are not well described.

OBJECTIVE

Our objective was to deduce smoothed age-specific centiles of circulating testosterone, DHT, and E2 in men using pooled data from population-based studies in three Australian cities from liquid chromatography-mass spectrometry steroid measurements in a single laboratory.

DESIGN, SETTING, AND PARTICIPANTS

We pooled data of 10 904 serum samples (serum testosterone, DHT, E2, age, height, and weight) from observational population-based studies in three major cities across Australia.

MAIN OUTCOME MEASURES

Age-specific smoothed centiles for serum testosterone, DHT, and E2 in men aged 35-100 years were deduced by large sample data analysis methods.

RESULTS

We found that serum testosterone, DHT, and E2 decline gradually from ages 35 onwards with a more marked decline after 80 years of age. Higher weight, BMI, and body surface area as well as shorter stature are associated with reduced serum testosterone, DHT, and E2.

CONCLUSIONS

Among Australian men, there is a gradual progressive population-wide decline in androgen status during male aging until the age of 80 years after which there is a more marked decline. Obesity and short stature are associated with reduced androgen status. Research into the age-related decline in androgen status should focus on the progressive accumulation of age-related comorbidities to better inform optimal clinical trial design.

Estimating age-specific trends in circulating testosterone and sex hormone-binding globulin in males and females across the lifespan

BACKGROUND

Age-specific trends of serum testosterone and sex hormone-binding globulin across the full lifespan have not been reported.

METHODS

We deduced age-specific trends in serum testosterone and sex hormone-binding globulin in males and females between ages 10 and 90 from a large sample of consecutive results from a single large pathology laboratory. Coded results of 110,712 consecutive blood samples requesting serum testosterone over seven years (2007-2013) comprising blood testosterone, sex hormone-binding globulin and calculated free testosterone together with gender and age were analysed create smoothed age-specific centiles (2.5%, 5%, 25%, 50%, 75%, 95%, 97.5%) for males and females.

RESULTS

These identified the pubertal increases in serum testosterone in males peaking at 20 years of age and remaining stable thereafter until the eighth decade. In females, circulating testosterone peaked in late adolescence and declined gradually over the next two decades but remained stable across menopause and beyond. After early childhood, serum sex hormone-binding globulin declines to a nadir in males at the age of 20 years and remains stable till the sixth decade with a gradual, progressive rise thereafter. In females, the sex hormone-binding globulin nadir is reached earlier with levels rising gradually and progressively with age thereafter and accelerating after the age of 70 years. Females also exhibit a second sex hormone-binding globulin peak during reproductive ages reflected only in upper centiles due to effects of pregnancy and oral contraceptive use in a significant minority of females.

CONCLUSIONS

This large sample of clinical data provides a comprehensive profile of androgen status across the lifespan from early adolescence to late old age.

Male reproductive disorders, diseases, and costs of exposure to endocrine-disrupting chemicals in the European Union

INTRODUCTION

Increasing evidence suggests that endocrine-disrupting chemicals (EDCs) contribute to male reproductive diseases and disorders.

PURPOSE

To estimate the incidence/prevalence of selected male reproductive disorders/diseases and associated economic costs that can be reasonably attributed to specific EDC exposures in the European Union (EU).

METHODS

An expert panel evaluated evidence for probability of causation using the Intergovernmental Panel on Climate Change weight-of-evidence characterization. Exposure-response relationships and reference levels were evaluated, and biomarker data were organized from carefully identified studies from the peer-reviewed literature to represent European exposure and approximate burden of disease as it occurred in 2010. The cost-of-illness estimation utilized multiple peer-reviewed sources.

RESULTS

The expert panel identified low epidemiological and strong toxicological evidence for male infertility attributable to phthalate exposure, with a 40-69% probability of causing 618,000 additional assisted reproductive technology procedures, costing €4.71 billion annually. Low epidemiological and strong toxicological evidence was also identified for cryptorchidism due to prenatal polybrominated diphenyl ether exposure, resulting in a 40-69% probability that 4615 cases result, at a cost of €130 million (sensitivity analysis, €117-130 million). A much more modest (0-19%) probability of causation in testicular cancer by polybrominated diphenyl ethers was identified due to very low epidemiological and weak toxicological evidence, with 6830 potential cases annually and costs of €848 million annually (sensitivity analysis, €313-848 million). The panel assigned 40-69% probability of lower T concentrations in 55- to 64-year-old men due to phthalate exposure, with 24 800 associated deaths annually and lost economic productivity of €7.96 billion.

CONCLUSIONS

EDCs may contribute substantially to male reproductive disorders and diseases, with nearly €15 billion annual associated costs in the EU. These estimates represent only a few EDCs for which there were sufficient epidemiological studies and those with the highest probability of causation. These public health costs should be considered as the EU contemplates regulatory action on EDCs.

The utility and dynamics of salivary sex hormone measurements in the National Social Life, Health, and Aging Project, Wave 2

OBJECTIVES

Sex hormones affect physical, mental, and social health, yet their role in mediating social effects on aging is understudied. To facilitate such analyses with the National Social Life, Health & Aging Project Wave 2, we summarize the conceptual background, collection protocols, laboratory assays, and data analysis strategies for biologically active (free) levels of testosterone, estradiol, progesterone, and dehydroepiandrosterone (DHEA).

METHOD

Saliva from passive drool was collected from returning Wave 1 respondents and non-respondents as well as their partners during an in-home interview. Specimens were frozen and sent to Dresden LabService GmbH for duplicate assays of biologically active steroids using identical assay kits from National Social Life, Health, and Aging Project (NSHAP) Wave 1 (SaliCap, Catalog No. RE69995). Overall, 2,772 testosterone, 2,504 estradiol, 2,714 progesterone, and 2,800 DHEA measurements are publically available for Wave 2 analyses. Through a series of weighted linear regressions, all 4 steroids are compared by gender and age and to Wave 1 measurements.

RESULTS

Men had higher levels of both free testosterone and progesterone than women; women and men had the same levels of estradiol and DHEA. Both free testosterone and DHEA decreased with age. We also found significant wave effects for all 4 sex hormones.

CONCLUSION

NSHAP Waves 1 and 2 are the first U.S. probability sample studies to measure these 4 salivary sex hormones simultaneously, providing individual profiles 5 years apart. Wave 2 data demonstrate differences by gender and trends by age that are similar to those found in other saliva-based and serum-based studies of free steroid levels. The differences between waves arising from the change in assay laboratory need to be adjusted in future longitudinal analyses using NSHAP Wave 1 and Wave 2 steroid data.

Urinary phthalate metabolites are associated with decreased serum testosterone in men, women, and children from NHANES 2011-2012

CONTEXT

There is evidence of declining trends in T levels among men in recent decades, as well as trends in related conditions at multiple life stages and in both sexes. There is also animal and limited human evidence that exposure to phthalates, chemicals found in plastics and personal care products, is associated with reduced androgen levels and associated disorders.

OBJECTIVE

To explore relationships between urinary concentrations of 13 phthalate metabolites and serum total T levels among men, women, and children when adjusting for important confounders and stratifying by sex and age (6-12, 12-20, 20-40, 40-60, and 60-80 y).

DESIGN

A cross-sectional study.

SETTING

US National Health and Nutrition Examination Survey, 2011-2012.

PATIENTS OR OTHER PARTICIPANTS

US general population.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Serum total T measured by isotope dilution-liquid chromatography-tandem mass spectrometry.

RESULTS

Multiple phthalates were associated with significantly reduced T in both sexes and in differing age groups. In females, the strongest and most consistent inverse relationships were found among women ages 40-60 years. In boys 6-12 years old, an interquartile range increase in metabolites of di-2-ethylhexyl phthalate was associated with a 29% (95% confidence interval, 6, 47) reduction in T. In adult men, the only significant or suggestive inverse associations between phthalates (metabolites of di-2-ethylhexyl phthalate and dibutyl phthalate) and T were observed among men ages 40-60 years.

CONCLUSIONS

Because T plays an important role in all life stages for both sexes, future efforts should focus on better defining these relationships and their broader impacts.

Performance of Massachusetts Male Aging Study (MMAS) and androgen deficiency in the aging male (ADAM) questionnaires in the prediction of free testosterone in patients aged 40 years or older treated in outpatient regimen

OBJECTIVE

At present, calculated free testosterone assessment is considered as the gold standard in diagnosing male hypogonadism. However, this assessment is not available for all the individuals diagnosed with decreased testicular function. The investigators of this study were, thus, prompted to evaluate whether the androgen deficiency in the aging male (ADAM) and the Massachusetts Male Ageing Study (MMAS) questionnaires could be used to replace biochemical parameters in the diagnosis for hypogonadism in men aged 40 years and above.

METHODS

We evaluated 460 men, aged 40 years and above, all volunteers of a screening program for prostate cancer based at the Hospital de Clínicas of Porto Alegre. In this study, we assessed the efficiency of the ADAM and MMAS questionnaires in diagnosing Brazilian men with low levels of total, calculated free and bioavailable testosterone.

RESULTS

The sensitivity of the ADAM questionnaire in diagnosing the calculated free testosterone was 73.6%, whereas specificity was 31.9%. ADAM could be used to properly classify our cohort into normal or hypogonadal individuals in 52.75% of the cases. The sensitivity of the MMAS questionnaire was 59.9%, whereas the specificity was 42.9%, resulting in a successful classification of 51.4% of the patients.

CONCLUSION

The ADAM and MMAS questionnaires showed adequate sensitivity in diagnosing male patients with low levels of free testosterone. However, because of the lack of specificity, these tools cannot replace calculated free testosterone assessments in men aged 40 years and above.

Possible fetal determinants of male infertility

Although common reproductive problems, such as male infertility and testicular cancer, present in adult life, strong evidence exists that these reproductive disorders might have a fetal origin. The evidence is derived not only from large epidemiological studies that show birth-cohort effects with regard to testicular cancer, levels of testosterone and semen quality, but also from histopathological observations. Many infertile men have histological signs of testicular dysgenesis, including Sertoli-cell-only tubules, immature undifferentiated Sertoli cells, microliths and Leydig cell nodules. The most severe gonadal symptoms occur in patients with disorders of sexual development (DSDs) who have genetic mutations, in whom even sex reversal of individuals with a 46,XY DSD can occur. However, patients with severe DSDs might represent only a small proportion of DSD cases, with milder forms of testicular dysgenesis potentially induced by exposure to environmental and lifestyle factors. Interestingly, maternal smoking during pregnancy has a stronger effect on spermatogenesis than a man's own smoking. Other lifestyle factors such as alcohol consumption and obesity might also have a role. However, increasing indirect evidence exists that exposure to ubiquitous endocrine disrupting chemicals, present at measurable concentrations in individuals, might affect development of human fetal testis. If confirmed, health policies to prevent male reproductive problems should not only target adult men, but also pregnant women and their children.

Fetal programming of adult Leydig cell function by androgenic effects on stem/progenitor cells

Fetal growth plays a role in programming of adult cardiometabolic disorders, which in men, are associated with lowered testosterone levels. Fetal growth and fetal androgen exposure can also predetermine testosterone levels in men, although how is unknown, because the adult Leydig cells (ALCs) that produce testosterone do not differentiate until puberty. To explain this conundrum, we hypothesized that stem cells for ALCs must be present in the fetal testis and might be susceptible to programming by fetal androgen exposure during masculinization. To address this hypothesis, we used ALC ablation/regeneration to identify that, in rats, ALCs derive from stem/progenitor cells that express chicken ovalbumin upstream promoter transcription factor II. These stem cells are abundant in the fetal testis of humans and rodents, and lineage tracing in mice shows that they develop into ALCs. The stem cells also express androgen receptors (ARs). Reduction in fetal androgen action through AR KO in mice or dibutyl phthalate (DBP) -induced reduction in intratesticular testosterone in rats reduced ALC stem cell number by ∼40% at birth to adulthood and induced compensated ALC failure (low/normal testosterone and elevated luteinizing hormone). In DBP-exposed males, this failure was probably explained by reduced testicular steroidogenic acute regulatory protein expression, which is associated with increased histone methylation (H3K27me3) in the proximal promoter. Accordingly, ALCs and ALC stem cells immunoexpressed increased H3K27me3, a change that was also evident in ALC stem cells in fetal testes. These studies highlight how a key component of male reproductive development can fundamentally reprogram adult hormone production (through an epigenetic change), which might affect lifetime disease risk.

Reproductive parameters in young men living in Rochester, New York

OBJECTIVE

To describe semen quality and reproductive hormone concentrations of young men living in Rochester, New York, and to compare these with published data from similar European and Japanese populations.

DESIGN

Cross-sectional study.

SETTING

University and college campuses in the Rochester, New York, area.

PATIENT(S)

Unselected young college students (n = 222).

INTERVENTION(S)

A physical examination, blood and semen samples, and completion of a brief questionnaire.

MAIN OUTCOME MEASURE(S)

Semen parameters and serum reproductive hormone levels.

RESULT(S)

Subjects were aged 18-22 years (median age, 19.5 years), predominantly Caucasian (81%), and nonsmokers (79%), with a mean (SD) body mass index of 25.5 (4.2) kg/m(2). Overall, median sperm concentration was 52 × 10(6)/mL (5th-95th percentiles: 7-181 × 10(6)/mL), median total sperm count was 158 × 10(6) (14-587 × 10(6)), and 23.1% and 15.8% of men had a sperm concentration below 20 × 10(6)/mL and 15 × 10(6)/mL, respectively. Few men had serum hormones falling outside clinically normal ranges. Median sperm concentrations and reproductive hormone levels were comparable to those seen in young men in Denmark, Finland, and Japan.

CONCLUSION(S)

Our study provides the first data in 70 years on semen quality and reproductive hormones in young men in the United States with unknown fertility. These data suggest that, overall, reproductive parameters in our study population of young college students from the northeastern United States are similar to those of young European and Japanese men.

Is rising obesity causing a secular (age-independent) decline in testosterone among American men?

The testosterone of men in industrial societies peaks in their twenties and tends to decline with increasing age. Apart from this individual-level decline, there have been reports of a secular (age-independent population-level) decline in testosterone among American and Scandinavian men during the past few decades, possibly an indication of declining male reproductive health. It has been suggested that both declines in testosterone (individual-level and population-level) are due to increasing male obesity because men in industrial society tend to add body fat as they age, and overall rates of obesity are increasing. Using an unusually large and lengthy longitudinal dataset (991 US Air Force veterans examined in six cycles over 20 years), we investigate the relationship of obesity to individual and population-level declines in testosterone. Over twenty years of study, longitudinal decline in mean testosterone was at least twice what would be expected from cross-sectional estimates of the aging decline. Men who put on weight intensified their testosterone decline, some greatly so, but even among those who held their weight constant or lost weight during the study, mean testosterone declined 117 ng/dl (19%) over 20 years. We have not identified the reason for secular decline in testosterone, but we exclude increasing obesity as a sufficient or primary explanation, and we deny the supposition that men who avoid excessive weight will maintain their youthful levels of testosterone.

Elderly men have low levels of anti-Müllerian hormone and inhibin B, but with high interpersonal variation: a cross-sectional study of the sertoli cell hormones in 615 community-dwelling men

The Sertoli cells of the testes secrete anti-Müllerian hormone (Müllerian inhibiting Substance, AMH) and inhibin B (InhB). AMH triggers the degeneration of the uterine precursor in male embryos, whereas InhB is part of the gonadal-pituitary axis for the regulation of sperm production in adults. However, both hormones are also putative regulators of homeostasis, and age-related changes in these hormones may therefore be important to the health status of elderly men. The levels of AMH in elderly men are unknown, with limited information being available about age-related changes in InhB. We have therefore used ELISAs to measure Sertoli cell hormone levels in 3 cohorts of community-dwelling men in New Zealand. In total, 615 men were examined, 493 of which were aged 65 or older. Serum AMH and InhB levels inversely correlated with age in men older than 50 years (p<0.001) but not in the younger men. A minority of elderly men had undetectable levels of AMH and InhB. The variation in hormone levels between similarly aged men increased with the age of men. AMH and InhB partially correlated with each other as expected (r = 0.48, p<0.001). However, the ratio of the two Sertoli hormones varied significantly between men, with this variation increasing with age. Elderly men selected for the absence of cardiovascular disease had AMH levels similar to those of young men whereas their InhB levels did not differ from aged-matched controls. These data suggests that Sertoli cell number and function changes with age, but with the extent and nature of the changes varying between men.

Clinical review: Anogenital distance or digit length ratio as measures of fetal androgen exposure: relationship to male reproductive development and its disorders

CONTEXT

Male reproductive disorders evident at birth or in young adulthood are remarkably common. They are hypothesized to comprise a testicular dysgenesis syndrome (TDS), with a fetal origin involving mild androgen deficiency.

EVIDENCE ACQUISITION

Testing this hypothesis requires "seeing back in time." Two ways have been proposed: measurement of anogenital distance (AGD), or measurement of the 2:4 digit length ratio. This review assesses the evidence that they reflect fetal androgen exposure and might be used to provide insight into the origin of TDS disorders.

EVIDENCE SYNTHESIS

Supporting evidence for AGD derives from rat experimental studies that identified a fetal masculinization programming window, within which androgen action determines adult reproductive organ size, TDS disorders, and AGD. In humans, AGD is positively correlated to testis size, sperm count/fertility, penis length, and T levels, consistent with rat experimental data. The 2:4 digit ratio also shows associations with these parameters, but inconsistently between studies; evidence that the 2:4 digit ratio accurately reflects fetal androgen exposure is also equivocal.

CONCLUSIONS

AGD appears to provide a reliable guide to fetal androgen exposure, although available data are limited. The next steps are to: standardize AGD measurement; obtain age-specific population data; and use AGD to evaluate the importance of fetal androgens in determining reproductive disorders and variation in testis/penis size and sperm count in the normal population. These studies should identify what, if any, clinical applications of AGD measurement are feasible--for example, its ability to predict adult-onset reproductive function and disorders.

Reproductive aging in men

Aging in men is associated with a decrease in serum testosterone levels due to attrition in testicular Leydig cells and slowing of the hypothalamic GnRH pulse generator. The practicing endocrinologist is frequently consulted for consideration of testosterone therapy in older men with late-onset hypogonadism (LOH), a condition that many clinicians fail to distinguish from organic hypogonadism. Recent data using syndromic definition show that only 2% of 40-80-year-old men have LOH. Co-morbidities and obesity strongly contribute to LOH, suggesting that testosterone is a biomarker of health. Hence, prevention and treatment of these co-morbidities might attenuate age-related decline in androgen levels.

Identification of a novel androgen receptor mutation in a family with multiple components compatible with the testicular dysgenesis syndrome

CONTEXT

Androgen signaling via the androgen receptor (AR) is essential for normal testis development and male reproductive functions. We describe a rare family with 3 males affected by a mild disorder of sex determination compatible with testicular dysgenesis syndrome (TDS), including subfertility, cryptorchidism, hypospadias, and testicular cancer, caused by a novel AR mutation.

OBJECTIVE

The aim of this study was to describe the phenotype of the affected males, characterize functionally the novel AR mutation, and discuss the significance of partial androgen insufficiency in the pathogenesis of TDS.

PARTICIPANTS

The proband, his first cousin, and a nephew underwent a detailed clinical investigation including genetic tests, whereas four female members of the family were tested for the specific AR mutation.

RESULTS

A novel AR mutation, c.2214T>G;p.Ile738Met, was identified in the affected family members. Functional analysis of the mutation in a gene-reporter assay showed a 50% reduction in AR-induced transcriptional activity. The affected males had elevated LH and T in accordance with decreased AR signaling. The histology and immunohistochemical profile of the testis tissue from the 2 patients with testicular cancer showed features consistent with insufficient testis development and TDS.

CONCLUSION

The presence of all hallmarks of TDS, including germ cell cancer, in a family with a novel AR mutation causing a partial decrease in AR function is in line with the concept that reduced androgen signaling may contribute to the development of TDS. It also seems consistent with the hypothesis that environmental factors interfering with this pathway can play a role in the pathogenesis of TDS.

Similar reference intervals for total testosterone in healthy young and elderly men: results from the Odense Androgen Study

CONTEXT

Ageing in men is associated with changes in levels of sex hormones.

OBJECTIVE

To evaluate differences in sex hormones in young and elderly men and the significance of comorbidity and fat mass on sex hormones in elderly men.

DESIGN

Cross-sectional.

PATIENTS

Seven hundred and eighty-three men aged 20-29 years and 600 men aged 60-74 years randomly recruited from the background population.

MEASUREMENTS

Sex hormones and sex hormone-binding globulin (SHBG) were measured, and reference intervals were determined in healthy individuals in both groups and in elderly men stratified according to whether they were obese or lean (waist circumference ≥102 cm).

RESULTS

Sex hormones were lower and SHBG higher in elderly men compared with the young cohort. Lower cut-offs for total testosterone (TT) in healthy, young and elderly men were similar [Lower cut-off (95% CI): Young: 11·7 (11·2-12·1) vs elderly: 11·2 (10·3-12·1) nmol/l], but lower and higher cut-offs of bioavailable testosterone (BT) and free testosterone (FT) were higher in young men. Higher levels of androgens were found in healthy elderly men compared with those with a chronic disease or obesity. Androgens were inversely associated with central fat mass (CFM), whereas SHBG was inversely and directly associated with CFM and lower extremity fat mass, respectively, in both young and elderly men.

CONCLUSION

Reference intervals for TT were comparable in healthy young and elderly men, but reference intervals for FT and BT were lower in elderly men due to higher levels of SHBG. Androgens and SHBG were lower in elderly men with chronic disease and inversely associated with CFM.

A cohort effect on serum testosterone levels in Finnish men

OBJECTIVE

To investigate whether a population-level decline in serum testosterone exists in Finnish men. In comparison with other European populations, Finnish men have compared well in the studies of reproductive health (i.e. semen quality, incidence of cryptorchidism and testicular cancer); thus, we expected no significant cohort-dependent decrease in serum testosterone.

METHODS

We analysed serum levels of testosterone, gonadotrophin and sex hormone binding globulin (SHBG) in 3271 men representing different ages (25-74 years) and birth cohorts within three large Finnish population surveys conducted in 1972, 1977 and 2002.

RESULTS

Serum testosterone levels decreased (from 25.3 nmol/l in 25- to 29-year-old men gradually to 16.9 nmol/l in 70- to 74-year-old men), whereas SHBG and gonadotrophin levels increased with increasing age. In addition, a significant secular trend in testosterone (total and free), SHBG and gonadotrophin levels was observed with lower levels in more recently born age-matched men. Serum testosterone level decreased in men aged 60-69 years from 21.9 nmol/l (men born 1913-1922) to 13.8 nmol/l (men born 1942-1951). These decreases remained significant following adjustment for BMI. An age-independent birth cohort effect existed on reproductive hormones measured in the Finnish men. In concert with the lower free testosterone levels, we observed lower gonadotrophin levels, suggesting that while there may be detrimental changes at the gonad level, the hypothalamus-pituitary-axis is not responding appropriately to this change.

CONCLUSIONS

The more recently born Finnish men have lower testosterone levels than their earlier born peers. This study offers no explanation for this substantial recent adverse development.

Phthalate excretion pattern and testicular function: a study of 881 healthy Danish men

BACKGROUND

In animals, some phthalates impair male reproductive development and function. Epidemiological studies have reported inconsistent evidence of associations between phthalates and markers of human testicular function.

OBJECTIVES

We aimed to provide estimates of the effects of phthalate exposure on reproductive hormone levels and semen quality in healthy men.

METHODS

A total of 881 men gave urine, serum, and semen samples. Serum levels of testosterone, estradiol (E2), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and inhibin-B; semen quality; and urinary concentrations of 14 phthalate metabolites, including metabolites of di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DiNP), were assessed. The proportions of DEHP and DiNP excreted as their respective primary metabolites [mono(2-ethylhexyl) phthalate (MEHP) and mono-isononyl phthalate (MiNP)] were calculated and expressed as percentages (%MEHP and %MiNP, respectively).

RESULTS

The free androgen index was 15% lower [95% confidence interval (CI): -23, -8%] for men in the highest %MiNP quartile compared to the lowest quartile (p < 0.001) after adjusting for confounders, and 9% lower (95% CI: -16, -1%) in the highest %MEHP quartile (p = 0.02). %MEHP and %MiNP were negatively associated with the ratio of testosterone/LH and testosterone/FSH. %MEHP was negatively associated with total testosterone, free testosterone, and ratio of testosterone/E(2). %MiNP was positively associated with SHBG. There was little evidence of associations between urinary phthalate metabolites or sums of phthalates with reproductive hormones or semen quality.

CONCLUSION

Our data suggest that both testosterone production and pituitary-hypothalamic feedback may be compromised in individuals excreting a high proportion of primary metabolites of long-chained phthalates relative to the proportion of secondary metabolites.

Frailty and sarcopenia: definitions and outcome parameters

An operational definition of musculoskeletal decline in older people is needed to allow development of interventions for prevention or treatment, as was developed for the treatment of osteoporosis. Frailty and sarcopenia are linked, but distinct, correlates of musculoskeletal aging that have many causes, including age-related changes in body composition, inflammation, and hormonal imbalance. With the emergence of a number of exciting candidate therapies to retard the loss of muscle mass with aging, the derivation of a consensual definition of sarcopenia and physical frailty becomes an urgent priority. Although several consensual definitions have been proposed, these require clinical validation. An operational definition, which might provide a threshold for treatment/trial inclusion, should incorporate a loss of muscle mass as well as evidence of a decrease in muscle strength and/or physical activity. Evidence is required for a link between improvements in the measures of muscle strength and/or physical activity and clinical outcomes to allow development of interventions to improve clinical outcomes in frail older patients.

Clinical correlates of sex steroids and gonadotropins in men over the late adulthood: the Framingham Heart Study

Low serum concentrations of sex steroids and gonadotropins in men have been associated with increased cardiometabolic risk and mortality, but the clinical correlates of these hormones in men over late adulthood are less clearly understood. We analysed up to five serial measurements of total testosterone (TT), dehydroepiandrosterone sulphate (DHEAS), follicle stimulating hormone (FSH), luteinizing hormone (LH) and total estradiol (EST) in older men in the original cohort of the Framingham Heart Study to determine the short- (2-years; 1,165 person-observations in 528 individuals) and long-term (up to 10-years follow-up; 2520 person-observations in 835 individuals with mean baseline age: 71.2 years) clinical correlates of these sex steroids and gonadotropins using multilevel modelling and Generalized Estimating Equations. Age, body mass index and pre-existing type 2 diabetes were inversely related to long-term TT concentrations, whereas higher systolic blood pressure showed a positive association. Furthermore, age and pre-existing cardiovascular disease (CVD) were inversely associated and HDL cholesterol concentrations positively associated with long-term DHEAS concentrations respectively. Analyses of short-term changes revealed age was inversely related to DHEAS, but positively related to FSH and LH concentrations. Our community-based study identified modifiable correlates of decreasing TT and DHEAS concentrations in elderly men, suggesting that maintenance of a low CVD risk factor burden may mitigate the age-related decline of these hormones over the late adulthood.

Urinary concentrations of di(2-ethylhexyl) phthalate metabolites and serum reproductive hormones: pooled analysis of fertile and infertile men

Urinary concentrations of metabolites of the anti-androgenic xenobiotic di-(2-ethylhexyl) phthalate (DEHP) were previously shown to be weakly associated with serum levels of several hormones in 2 disparate US populations: partners of pregnant women participating in the Study for Future Families and partners in infertile couples from Massachusetts General Hospital infertility clinic. The observed associations between phthalate metabolites and reproductive hormones were robust and insensitive to the characteristics of the subpopulation or the laboratory in which the hormones were measured, despite the fact that these 2 populations span a range of fertility, urinary phthalate metabolites, and reproductive hormone levels. We therefore examined associations between urinary metabolites of DEHP and reproductive hormones-follicle-stimulating hormone, luteinizing hormone, testosterone (T), inhibin B, and estradiol (E(2))-and sex hormone-binding globulin (SHBG) in the pooled population. The magnitude of the associations seen were similar to those reported for each population separately, but effect estimates were more precise because of the increased sample size and the greater range of phthalate metabolite concentrations and hormone levels. Urinary concentrations of 3 metabolites of DEHP [mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP)] were inversely associated with the free androgen index (FAI = T/SHBG) and calculated free testosterone. Urinary concentrations of MEHHP and MEOHP were positively associated with SHBG, and MEHP was inversely associated with E(2). No other phthalate metabolites were associated with serum hormones, consistent with results in each population. Our results in this diverse population suggest that DEHP exposure is robustly associated with some male sex steroid hormones.

Secular trends in sex hormones and fractures in men and women

OBJECTIVE

To study secular trends in sex hormones, anthropometry, bone measures and fractures.

DESIGN

A random population sample was studied twice and subjects of similar age group were compared 13 years apart.

METHODS

X-ray-verified fractures were retrieved from a random population sample of 2400 men and women (participants 1616=67%) aged 25-64 years from the WHO, MONICA Project in Gothenburg, Sweden, in 1995 and 2008. Fasting serum hormones and calcaneal ultrasound were measured in every fourth subject. In fertile women, measurements were performed on cycle day interval 7-9.

RESULTS

In 2008, men had lower serum free testosterone than men of similar age in 1995 (P<0.001). Body composition, physical activity and fracture incidence were similar. In women, hormone replacement therapy (HRT) was lower in 2008, 7 vs 28% (P<0.0001), as was serum oestradiol, although use of tranquilisers and leisure time physical activity were higher. In 2008, the fracture incidence was higher in postmenopausal women, 29 vs 17% (P<0.001), and vertebral crush had increased from 8 to 19% of all fractures (P=0.031). Serum cholesterol and triglycerides were lower in all subjects in 2008 compared with that in 1995.

CONCLUSIONS

Secular trends were observed with lower serum testosterone in men in 2008, but no effect was seen on the fracture incidence of these fairly young men. In postmenopausal women in 2008, there was a higher fracture incidence along with more vertebral compressions. Lower HRT use, lower serum oestradiol and higher fall risk exposure due with more tranquilisers and leisure time physical activity in 2008 may explain the results.

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.

Semen variation in a population of fertile donors: evaluation in a French centre over a 34-year period

Although it has been suspected that there is a decrease in semen quality over time, the results reported to date remain debatable because of methodological issues. The aim of the study reported here was to investigate the evolution of semen quality over time in a population of 1114 fertile candidates for sperm donation at CECOS, Tours, between 1976 and 2009. We investigated semen volume, sperm concentration, progressive motility, vitality, percentage of normal forms and multiple abnormalities index of the first ejaculate in this population. We did not find a decline in semen volume, whereas we observed a significant decrease in total sperm count (from 443.2 million in 1976 to 300.2 million in 2009), motility (from 64% in 1976 to 49% in 2009) and vitality (from 88% to 80%). Moreover, a significant decline in the percentage of normal forms was noted between 1976 and 1997 (from 67% to 26%) with a steady rise in the multiple abnormalities index between 1998 and 2009 (from 1.19 to 1.65). This study involving a population of fertile men from a restricted area revealed various degrees of decline in semen parameters over a period of 34 years. These findings will have to be compared with findings in other geographical areas.

Survey for late-onset hypogonadism among old and middle-aged males in Shanghai communities

This study sought to investigate late-onset hypogonadism (LOH) in old and middle-aged males in Shanghai communities, using symptom score evaluation systems and measurements of sex hormone levels. One thousand cases of males aged 40-70 years were investigated. The aging male symptoms (AMS) scale and androgen deficiency in aging males (ADAM) questionnaire were used at the beginning of the investigation, followed by measurement of the sex hormone-related factors (total testosterone (TT), free testosterone (fT), sex hormone-binding globulin (SHBG) and bioavailability of testosterone (Bio-T)). There were 977 valid questionnaires. The LOH-positive rates shown by AMS and ADAM were 59.88% and 84.65%, respectively; values increased with the age of the patients. There were 946 results related to sex hormone measurements, which showed the following results: TT was not related to aging (P>0.05); levels of SHBG increased with age; and fT and Bio-T decreased with age. There was a significant difference in fT between LOH-positive and LOH-negative patients, as shown by the ADAM. In summary, TT levels were not related to aging, even though SHBG did increase while fT and Bio-T decreased with aging. Clinically, the diagnosis of LOH cannot be based on serum TT level.

'Idiopathic' partial androgen insensitivity syndrome in 28 newborn and infant males: impact of prenatal exposure to environmental endocrine disruptor chemicals?

OBJECTIVE

46,XY disorders of sex differentiation (46,XY DSD) can be due to a testis determination defect, an androgen biosynthesis defect, or androgen resistance (complete or partial androgen insensitivity syndrome (PAIS), or 5α reductase deficiency). We aimed to evaluate the impact of a prenatal contamination by environmental xenoestrogens in 'idiopathic' PAIS-like phenotype.

SUBJECTS

We investigated 28 newborn/infant males with 46,XY DSD, normal androgen production, and no androgen receptor or steroid-5αR type II enzyme (SRD5A2) gene mutations.

METHODS

To exclude other genetic defects, we sequenced the steroidogenic factor 1 (SF1) and mastermind-like domain-containing 1 (MAMLD1) genes, which were recently found to be associated with the PAIS-like phenotype. Parents were interviewed about their environmental/occupational exposure to endocrine disrupting chemicals (EDCs) before/during the patients' fetal life. Total estrogenic bioactivity of patient serum was analyzed by ultrasensitive bioassay.

RESULTS

All the patients had normal SF1 sequence and one patient showed a double polymorphism of MAMLD1. Eleven (39.3%) of the 28 patients had reported parental fetal exposure to EDCs. The mean estrogenic bioactivity in these 11 patients with fetal EDC exposure (6.65 ± 8.07 pg/ml) versus 17 cases without contamination (1.27 ± 0.34 pg/ml) and controls (1.06 ± 0.44 pg/ml; P<0.05) was elevated.

CONCLUSIONS

Our results indicate that the 'idiopathic' PAIS-like phenotype may in some cases be related to EDC contamination during fetal life.

Prenatal environmental risk factors for genital malformations in a population of 1442 French male newborns: a nested case-control study

BACKGROUND

Over the past decades, an increasing trend in male external genital malformations such as cryptorchidism and hypospadias has led to the suspicion that environmental chemicals are detrimental to male fetal sexual development. Several environmental pollutants, including organochlorine pesticides, polychlorinated biphenyls, bisphenol A, phthalates, dioxins and furans have estrogenic and anti-androgenic activity and are thus considered as endocrine-disrupting chemicals (EDCs). Since male sex differentiation is critically dependent on the normal production and action of androgens during fetal life, EDCs may be able to alter normal male sex differentiation.

OBJECTIVE

The objective of this study was to determine the incidence of external genital malformations in a population of full-term newborn males in southern France. We also performed a case-control study to identify the risk factors for male external genital malformations, with a focus on parental occupational exposure to EDCs.

METHODS

Over a 16-month period, 1615 full-term newborn males with a birth weight above 2500 g were registered on a level-1 maternity ward, and the same pediatrician systematically examined 1442 of them (89%) for cryptorchidism, hypospadias and micropenis. For every male newborn with genital malformation, we enrolled nearly two males matched for age, parity and term. All parents of the case and control newborns were interviewed about pregnancy aspects, personal characteristics, lifestyle and their occupational exposure to EDCs using a detailed questionnaire. RESULTS We report 39 cases of genital malformation (2.70%), with 18 cases of cryptorchidism (1.25%), 14 of hypospadias (0.97%), 5 of micropenis (0.35%) and 2 of 46,XY disorders of sexual differentiation (DSD; 0.14%). We observed a significant relationship between newborn cryptorchidism, hypospadias or micropenis and parental occupational exposure to pesticides [odds ratio (OR) = 4.41; 95% confidence interval (95% CI), 1.21-16.00]. Familial clustering for male external genital malformations (OR = 7.25; 95% CI, 0.70-74.30) and medications taken by mothers during pregnancy (OR = 5.87; 95% CI, 0.93-37.00) were associated with the risk of cryptorchidism, hypospadias and micropenis, although the association was not statistically significant.

CONCLUSIONS

Although the causes of male genital malformation are multifactorial, our data support the hypothesis that prenatal contamination by pesticides may be a potential risk factor for newborn male external genital malformation and it should thus be routinely investigated in all undervirilized newborn males.

Associations between urinary metabolites of di(2-ethylhexyl) phthalate and reproductive hormones in fertile men

Widely used man-made chemicals, including phthalates, can induce hormonal alterations through a variety of cellular and molecular mechanisms. A number of rodent and observational studies have consistently demonstrated the anti-androgenic effect of several phthalates. However, there are only limited data on the relationship between exposure to these chemicals and reproductive hormone levels in men. All men (n=425) were partners of pregnant women who participated in the Study for Future Families in five US cities and provided urine and serum samples on the same day. Eleven phthalate metabolites were measured in urine and serum samples were analysed for reproductive hormones, including follicle-stimulating hormone, luteinizing hormone, testosterone, inhibin B and oestradiol and sex hormone-binding globulin (SHBG). Pearson correlations and parametric tests were used for unadjusted analyses, and multiple linear regression analysis was performed controlling for appropriate covariates. We observed weak or no associations with urinary phthalates other than di(2-ethylhexyl) phthalate (DEHP). All measures of testosterone [total, calculated free testosterone and the free androgen index (FAI)] were inversely correlated with the urinary concentrations of four DEHP metabolites. After adjustment by appropriate covariates, there was no longer an association between urinary DEHP metabolite concentrations and total testosterone levels; however, FAI was significantly associated with the urinary concentrations of several DEHP metabolites. SHBG was positively related to the urinary concentrations of mono(2-ethylhexyl) phthalate, but not with other DEHP metabolites, an association that was attenuated after adjustment. Our results suggest that DEHP exposure of fertile men is associated with minor alterations of markers of free testosterone.

Shorter anogenital distance predicts poorer semen quality in young men in Rochester, New York

BACKGROUND

In male rodents, anogenital distance (AGD) provides a sensitive and continuous correlate of androgen exposure in the intrauterine environment and predicts later reproductive success. Some endocrine-disrupting chemicals can alter male reproductive tract development, including shortening AGD, in both rodents and humans. Whether AGD is related to semen quality in human is unknown.

OBJECTIVE

We examined associations between AGD and semen parameters in adult males.

METHODS

We used multiple regression analyses to model the relationships between sperm parameters and two alternative measures of AGD [from the anus to the posterior base of the scrotum (AGD(AS)) and to the cephalad insertion of the penis (AGD(AP))] in 126 volunteers in Rochester, New York.

RESULTS

AGD(AS), but not AGD(AP), was associated with sperm concentration, motility, morphology, total sperm count, and total motile count (p-values, 0.002-0.048). Men with AGD(AS) below (vs. above) the median were 7.3 times more likely (95% confidence interval, 2.5-21.6) to have a low sperm concentration (< 20 × 10⁶/mL). For a typical study participant, sperm concentrations were 34.7 × 10⁶/mL and 51.6 × 10⁶/mL at the 25th and 75th percentiles of (adjusted) AGD(AS).

CONCLUSIONS

In our population, AGD(AS) was a strong correlate of all semen parameters and a predictor of low sperm concentration. In animals, male AGD at birth reflects androgen levels during the masculinization programming window and predicts adult AGD and reproductive function. Our results suggest, therefore, that the androgenic environment during early fetal life exerts a fundamental influence on both AGD and adult sperm counts in humans, as demonstrated in rodents.

Endocrinology of the aging male

The endocrinology of the aging male is complex, with multiple hormones along the hypothalamic-pituitary-testicular (HPT) axis interacting with one another in feedback. As men age, there is a small and progressive (not precipitous, as in women) decline in several sex hormones, in particular testosterone and dehydroepiandrosterone, and related increases in luteinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin. The importance of these changes is wide-ranging because of the ubiquitous role of sex hormones in male physiology. This chapter discusses the endocrinology of the aging male. We provide an overview of the regulation of the HPT axis with an emphasis on the changes that occur with aging and the measurement of gonadal steroids, including hormone pulsatility, within-subject and circadian variations. The difficulties of assessing the symptoms of late-onset hypogonadism are highlighted. There is a comprehensive discussion of the epidemiology of sex hormone changes, including their age associations, prevalence of symptomatic hypogonadism, secular changes, risk factors, and the association of sex hormones with outcomes.

Associations between longitudinal changes in serum estrogen, testosterone, and bioavailable testosterone and changes in benign urologic outcomes

Some men have rapid increases in benign prostatic enlargement and lower urinary tract symptoms (LUTS), and it is not clear how sex steroid hormones contribute to the rates of change in these urologic outcomes. Therefore, the authors conducted a population-based cohort study of 648 men residing in Olmsted County, Minnesota, from 1990 to 2007, to examine associations between baseline sex steroid hormones, the rate of change in these hormones, and the rates of change in LUTS, maximum urinary flow rate, and prostate volume. Annual changes in hormone levels and urologic outcomes were calculated using mixed-effects regression models. Associations between hormone variables and rates of change in urologic outcomes were assessed with linear regression models. Higher baseline estradiol levels and rapid declines in estradiol over time were associated with rapid increases in LUTS and rapid decreases in maximum flow rate. Lower baseline bioavailable testosterone levels and more rapid declines in bioavailable testosterone were associated with more rapid increases in prostate volume. These results suggest that both absolute sex steroid hormone levels and the rates at which the levels change may be important in the development of urologic conditions in aging men.

Low testosterone concentrations and the symptoms of testosterone deficiency according to the Androgen Deficiency in Ageing Males (ADAM) and Ageing Males' Symptoms rating scale (AMS) questionnaires

OBJECTIVE

First, to assess the association between the concentration of serum testosterone and the symptoms of testosterone deficiency according to two screening questionnaires. Second, to investigate the effects in elderly men with a low-normal testosterone concentration of testosterone supplementation over a period of 6 months on symptoms of testosterone deficiency according to the screening questionnaires.

DESIGN, SETTING AND PARTICIPANTS

A total of 587 men between 60 and 80 years of age with an eligible serum testosterone measurement and completion of the screening questionnaires were included in the study. Of these 587 men, 237 men with testosterone levels <13·7 nmol/l were included in a double-blind, randomized, placebo-controlled trial of testosterone supplementation.

INTERVENTION

One hundred and sixty milligrams per day of oral testosterone undecanoate or a matching placebo for 6 months.

MEASUREMENTS

The Androgen Deficiency in Ageing Males (ADAM) and the Ageing Males' Symptoms rating scale (AMS) questionnaires.

RESULTS

There was no significant association between the total testosterone concentration and the scores on the two questionnaires. However, age was significantly associated with the scores on the ADAM (OR 1·14, 95% CI 1·05-1·23) and the AMS (OR 1·03, 95% CI 1·01-1·08) questionnaire. After supplementation with testosterone, there were no effects on the scores on the two questionnaires in the testosterone group compared with the placebo group.

CONCLUSION

The findings do not support the use of the ADAM or AMS questionnaire in the evaluation of late-onset hypogonadism in ageing men. Moreover, 6 months of oral testosterone supplementation had no significant effect on scores of the ADAM and AMS questionnaire in this group of elderly men with low-normal testosterone levels.

Prevalence, incidence and risk factors of testosterone deficiency in a population-based cohort of men: results from the study of health in Pomerania

OBJECTIVE

Low total testosterone levels (TT) have been associated with increased morbidity and mortality. However, the prevalence and incidence of testosterone deficiency (TD) in association with its risk has not been assessed systematically to date.

METHODS

Data from the prospective population-based Study of Health in Pomerania were used. From the 2117 men aged 20-79 years at baseline, 1490 men with complete TT data were analysed. Crude and age-specific prevalence and incidence rates of TD were estimated by TT levels below the age-specific 10th percentile. Analysis of covariance and Poisson regression models were used to assess the association of socio-demographic characteristics, health-related lifestyle, as well as somatometric, medical and laboratory measures with risk of incident TD.

RESULTS

TD baseline prevalence was 10.4% (N = 155) and incidence 11.7 per 1000 person-years. TT levels showed a significant age-related decline with an unadjusted rate of 0.05 nmol/l per year. Obesity, metabolic syndrome, diabetes and dyslipidaemia were identified as risk factors of incident TD. Subpopulations of men without the revealed risk factors at both examinations maintained constant TT levels over time.

CONCLUSIONS

Besides aging alone, lifestyle and different comorbidities were associated with TT level decline, suggesting that the age-related TT decline may be at least partly prevented through the management of potentially modifiable risk factors and health related behaviour.