Reproductive functions in young fathers and grandfathers

Analysis of diurnal variation in serum testosterone levels in men with symptoms of testosterone deficiency

BACKGROUND

Testosterone (T) plays a crucial role in various physiological functions in men, and understanding the variations in T levels during the day is essential for diagnosing and treating testosterone deficiency (TD).

AIM

We sought to evaluate the reduction in serum total T (TT) levels throughout the day in men with symptoms of testosterone deficiency and to determine the variables having an impact on the extent of this decline.

METHODS

The study population consisted of a group of men who within 3 months of each other had all undergone both early morning and afternoon TT level measurements. We did not include patients with a history of a prior orchiectomy, testosterone levels below 100 ng/dL or above 1000 ng/dL, a history of androgen deprivation therapy, or patients on T therapy. Statistical analyses were conducted using descriptive statistics, t-tests, chi-square tests, and correlation calculations. Liquid chromatography-tandem mass spectrometry was used to measure TT, and a change in TT levels greater than 100 ng/dL was considered significant. Using multivariable and univariable analysis, we attempted to define predictors of a decrease in afternoon TT levels.

OUTCOMES

The majority of men showed no significant difference in T levels between morning and afternoon.

RESULTS

In total, 506 men with a median age of 65 years were analyzed. The most common comorbidities were hypertension and hyperlipidemia. Levels of TT were measured in the morning and afternoon, and no significant differences in mean T levels based on the time of the test were found. Age was not significantly associated with T levels.

CLINICAL IMPLICATIONS

There was a weak negative correlation between age and the difference between morning and afternoon T levels, with younger men showing more significant variations in T levels. The most considerable differences in T levels were observed in men younger than 30 years. There were no predictors of the magnitude of the T decrease in the afternoon.

STRENGTHS AND LIMITATIONS

Strengths of the study include the number of subjects and the use of liquid chromatography-tandem mass spectrometry for T measurement. Limitations include failure to measure morning and afternoon T levels on the same day, the retrospective nature of the study, and a smaller sample size of patients younger than 30 years.

CONCLUSION

In this study we found no strong link between age and daily T fluctuation, but we observed a decrease in the magnitude of variation with aging. The group experiencing the most significant decline in daily T had higher morning and consistently normal afternoon T levels.

The Effect of Age on Semen Quality Among Male Partners of Infertile Couples: An Observational Study in a Tertiary Care Center in Eastern India

INTRODUCTION

Male infertility contributes to a significant proportion of infertility cases, and advanced paternal age has been suggested to affect semen quality and fertility. However, the relationship between age and semen quality remains inconclusive, with conflicting findings reported in the literature. This study aimed to investigate the effect of age on semen quality among male partners of infertile couples in a tertiary care center in eastern India.

METHODS

A cross-sectional observational study was conducted, involving 390 male participants aged 21-50 years, who were referred to the andrology laboratory for semen analysis between January 2019 and December 2022. Participants were categorized into three age groups (21-30, 31-40, and 41-50 years). Semen parameters, including sperm concentration, semen volume, motility, and morphology, were assessed according to the World Health Organization guidelines.

RESULTS

Among the participants, no significant differences were observed in semen volume, motility, and morphology across different age groups. However, a statistically significant difference in sperm concentration among the three age groups was observed (p = 0.022). Spearman correlation analysis revealed a positive correlation between age and sperm concentration (r = 0.124, p = 0.013) as well as total sperm count (r = 0.10, p = 0.049).

CONCLUSION

In this study, no significant decline in semen quality with age was found among male partners of infertile couples aged 21-50 years. These findings highlight the complex relationship between age and semen quality and emphasize the need for further research to better understand the underlying mechanisms and provide more conclusive evidence regarding the impact of age on male fertility.

Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries

BACKGROUND

Numerous studies have reported declines in semen quality and other markers of male reproductive health. Our previous meta-analysis reported a significant decrease in sperm concentration (SC) and total sperm count (TSC) among men from North America-Europe-Australia (NEA) based on studies published during 1981-2013. At that time, there were too few studies with data from South/Central America-Asia-Africa (SAA) to reliably estimate trends among men from these continents.

OBJECTIVE AND RATIONALE

The aim of this study was to examine trends in sperm count among men from all continents. The broader implications of a global decline in sperm count, the knowledge gaps left unfilled by our prior analysis and the controversies surrounding this issue warranted an up-to-date meta-analysis.

SEARCH METHODS

We searched PubMed/MEDLINE and EMBASE to identify studies of human SC and TSC published during 2014-2019. After review of 2936 abstracts and 868 full articles, 44 estimates of SC and TSC from 38 studies met the protocol criteria. Data were extracted on semen parameters (SC, TSC, semen volume), collection year and covariates. Combining these new data with data from our previous meta-analysis, the current meta-analysis includes results from 223 studies, yielding 288 estimates based on semen samples collected 1973-2018. Slopes of SC and TSC were estimated as functions of sample collection year using simple linear regression as well as weighted meta-regression. The latter models were adjusted for predetermined covariates and examined for modification by fertility status (unselected by fertility versus fertile), and by two groups of continents: NEA and SAA. These analyses were repeated for data collected post-2000. Multiple sensitivity analyses were conducted to examine assumptions, including linearity.

OUTCOMES

Overall, SC declined appreciably between 1973 and 2018 (slope in the simple linear model: -0.87 million/ml/year, 95% CI: -0.89 to -0.86; P < 0.001). In an adjusted meta-regression model, which included two interaction terms [time × fertility group (P = 0.012) and time × continents (P = 0.058)], declines were seen among unselected men from NEA (-1.27; -1.78 to -0.77; P < 0.001) and unselected men from SAA (-0.65; -1.29 to -0.01; P = 0.045) and fertile men from NEA (-0.50; -1.00 to -0.01; P = 0.046). Among unselected men from all continents, the mean SC declined by 51.6% between 1973 and 2018 (-1.17: -1.66 to -0.68; P < 0.001). The slope for SC among unselected men was steeper in a model restricted to post-2000 data (-1.73: -3.23 to -0.24; P = 0.024) and the percent decline per year doubled, increasing from 1.16% post-1972 to 2.64% post-2000. Results were similar for TSC, with a 62.3% overall decline among unselected men (-4.70 million/year; -6.56 to -2.83; P < 0.001) in the adjusted meta-regression model. All results changed only minimally in multiple sensitivity analyses.

WIDER IMPLICATIONS

This analysis is the first to report a decline in sperm count among unselected men from South/Central America-Asia-Africa, in contrast to our previous meta-analysis that was underpowered to examine those continents. Furthermore, data suggest that this world-wide decline is continuing in the 21st century at an accelerated pace. Research on the causes of this continuing decline and actions to prevent further disruption of male reproductive health are urgently needed.

Single-cell analysis of human testis aging and correlation with elevated body mass index

Aging men display reduced reproductive health; however, testis aging is poorly understood at the molecular and genomic levels. Here, we utilized single-cell RNA-seq to profile over 44,000 cells from both young and older men and examined age-related changes in germline development and in the testicular somatic cells. Age-related changes in spermatogonial stem cells appeared modest, whereas age-related dysregulation of spermatogenesis and somatic cells ranged from moderate to severe. Altered pathways included signaling and inflammation in multiple cell types, metabolic signaling in Sertoli cells, hedgehog signaling and testosterone production in Leydig cells, cell death and growth in testicular peritubular cells, and possible developmental regression in both Leydig and peritubular cells. Remarkably, the extent of dysregulation correlated with body mass index in older but not in younger men. Collectively, we reveal candidate molecular mechanisms underlying the complex testicular changes conferred by aging and their possible exacerbation by concurrent chronic conditions such as obesity.

Environmental factors in declining human fertility

A severe decline in child births has occurred over the past half century, which will lead to considerable population declines, particularly in industrialized regions. A crucial question is whether this decline can be explained by economic and behavioural factors alone, as suggested by demographic reports, or to what degree biological factors are also involved. Here, we discuss data suggesting that human reproductive health is deteriorating in industrialized regions. Widespread infertility and the need for assisted reproduction due to poor semen quality and/or oocyte failure are now major health issues. Other indicators of declining reproductive health include a worldwide increasing incidence in testicular cancer among young men and alterations in twinning frequency. There is also evidence of a parallel decline in rates of legal abortions, revealing a deterioration in total conception rates. Subtle alterations in fertility rates were already visible around 1900, and most industrialized regions now have rates below levels required to sustain their populations. We hypothesize that these reproductive health problems are partially linked to increasing human exposures to chemicals originating directly or indirectly from fossil fuels. If the current infertility epidemic is indeed linked to such exposures, decisive regulatory action underpinned by unconventional, interdisciplinary research collaborations will be needed to reverse the trends.

Age-Related Alterations in the Testicular Proteome of a Non-Human Primate

Aging of human testis and associated cellular changes is difficult to assess. Therefore, we used a translational, non-human primate model to get insights into underlying cellular and biochemical processes. Using proteomics and immunohistochemistry, we analyzed testicular tissue of young (age 2 to 3) and old (age 10 to 12) common marmosets (Callithrix jacchus). Using a mass spectrometry-based proteomics approach, we identified 63,124 peptides, which could be assigned to 5924 proteins. Among them, we found proteins specific for germ cells and somatic cells, such as Leydig and Sertoli cells. Quantitative analysis showed 31 differentially abundant proteins, of which 29 proteins were more abundant in older animals. An increased abundance of anti-proliferative proteins, among them CDKN2A, indicate reduced cell proliferation in old testes. Additionally, an increased abundance of several small leucine rich repeat proteoglycans and other extracellular matrix proteins was observed, which may be related to impaired cell migration and fibrotic events. Furthermore, an increased abundance of proteins with inhibitory roles in smooth muscle cell contraction like CNN1 indicates functional alterations in testicular peritubular cells and may mirror a reduced capacity of these cells to contract in old testes.

18 F-FDG PET/CT use in functional assessment of the testes: A systematic review

INTRODUCTION

Our study analysed previous studies employing positron emission tomography with co-registered computer tomography (PET/CT) in andrological patient evaluation and assessed the differences in 2-[¹⁸ F]F-fluoro-2'-deoxyglucose (FDG) uptake between three groups: healthy testes, benign and malignant testicular pathology.

METHODS

Medline and Embase were systematically searched for studies involving FDG-PET/CT imaging of testes with results expressed as mean standardised uptake value (SUV_mean ). A one-way ANOVA was used to compare SUV_mean between three groups. All papers assessing andrological parameters were pooled to compare fertility data.

RESULTS

Seventeen studies, including three relating to fertility diagnosis, with a total of 830 patients, were included in the review. One-way ANOVA showed a statistical difference between mean values of tracer SUV_mean in healthy and malignant testes (Dif. = -2.77, 95% CI = -4.32 to 1.21, p < 0.01) as well as benign and malignant (Dif. = -2.95, 95% CI = -4.33 to -1.21, p < 0.01) but no difference between healthy and benign (Dif. = 0.19, 95% CI = -0.96 to 1.33, p = 0.90). There is some evidence to suggest that FDG uptake and testicular volume are positively correlated to total sperm count, sperm concentration and sperm motility and that germ cells are likely to account for the majority of testicular FDG accumulation.

CONCLUSION

Our findings indicate that malignant testicular lesions demonstrate a significantly higher FDG uptake than benign testicular lesions or healthy testes. Some evidence also suggests that FDG-PET could visualise metabolic activity and thus spermatogenesis; however more studies are required to determine whether FDG-PET could also be used to diagnose infertility. Further studies should focus on correlating both sex hormone-serum levels and semen analysis results with imaging data.

The European Academy of Andrology (EAA) ultrasound study on healthy, fertile men: Scrotal ultrasound reference ranges and associations with clinical, seminal, and biochemical characteristics

BACKGROUND

Scrotal color Doppler ultrasound (CDUS) still suffers from lack of standardization. Hence, the European Academy of Andrology (EAA) has promoted a multicenter study to assess the CDUS characteristics of healthy fertile men (HFM) to obtain normative parameters.

OBJECTIVES

To report and discuss the scrotal organs CDUS reference ranges and characteristics in HFM and their associations with clinical, seminal, and biochemical parameters.

METHODS

A cohort of 248 HFM (35.3 ± 5.9years) was studied, evaluating, on the same day, clinical, biochemical, seminal, and scrotal CDUS following Standard Operating Procedures.

RESULTS

The CDUS reference range and characteristics of the scrotal organs of HFM are reported here. CDUS showed a higher accuracy than physical examination in detecting scrotal abnormalities. Prader orchidometer (PO)- and US-measured testicular volume (TV) were closely related. The US-assessed TV with the ellipsoid formula showed the best correlation with the PO-TV. The mean TV of HFM was ~ 17 ml. The lowest reference limit for right and left testis was 12 and 11 ml, thresholds defining testicular hypotrophy. The highest reference limit for epididymal head, tail, and vas deferens was 12, 6, and 4.5 mm, respectively. Mean TV was associated positively with sperm concentration and total count and negatively with gonadotropins levels and pulse pressure. Subjects with testicular inhomogeneity or calcifications showed lower sperm vitality and concentration, respectively, than the rest of the sample. Sperm normal morphology and progressive motility were positively associated with epididymal head size/vascularization and vas deferens size, respectively. Increased epididymis and vas deferens sizes were associated with MAR test positivity. Decreased epididymal tail homogeneity/vascularization were positively associated with waistline, which was negatively associated with intratesticular vascularization. CDUS varicocele was detected in 37.2% of men and was not associated with seminal or hormonal parameters. Scrotal CDUS parameters were not associated with time to pregnancy, number of children, history of miscarriage.

CONCLUSIONS

The present findings will help in better understanding male infertility pathophysiology, improving its management.

Proteomic Insights into Senescence of Testicular Peritubular Cells from a Nonhuman Primate Model

Age-related changes in the human testis may include morphological alterations, disturbed steroidogenesis, and impaired spermatogenesis. However, the specific impact of cell age remains poorly understood and difficult to assess. Testicular peritubular cells fulfill essential functions, including sperm transport, contributions to the spermatogonial stem cell niche, and paracrine interactions within the testis. To study their role in age-associated decline of testicular functions, we performed comprehensive proteome and secretome analyses of repeatedly passaged peritubular cells from Callithrix jacchus. This nonhuman primate model better reflects the human testicular biology than rodents and further gives access to young donors unavailable from humans. Among 5095 identified proteins, 583 were differentially abundant between samples with low and high passage numbers. The alterations indicate a reduced ability of senescent peritubular cells to contract and secrete proteins, as well as disturbances in nuclear factor (NF)-κB signaling and a reduced capacity to handle reactive oxygen species. Since this in vitro model may not exactly mirror all molecular aspects of in vivo aging, we investigated the proteomes and secretomes of testicular peritubular cells from young and old donors. Even though the age-related alterations at the protein level were less pronounced, we found evidence for impaired protein secretion, altered NF-κB signaling, and reduced contractility of these in vivo aged peritubular cells.

A germ cell-specific ageing pattern in otherwise healthy men

Life‐long sperm production leads to the assumption that male fecundity remains unchanged throughout life. However, recently it was shown that paternal age has profound consequences for male fertility and offspring health. Paternal age effects are caused by an accumulation of germ cell mutations over time, causing severe congenital diseases. Apart from these well‐described cases, molecular patterns of ageing in germ cells and their impact on DNA integrity have not been studied in detail. In this study, we aimed to assess the effects of ‘pure’ ageing on male reproductive health and germ cell quality. We assembled a cohort of 198 healthy men (18–84 years) for which end points such as semen and hormone profiles, sexual health and well‐being, and sperm DNA parameters were evaluated. Sperm production and hormonal profiles were maintained at physiological levels over a period of six decades. In contrast, we identified a germ cell‐specific ageing pattern characterized by a steady increase of telomere length in sperm and a sharp increase in sperm DNA instability, particularly after the sixth decade. Importantly, we found sperm DNA methylation changes in 236 regions, mostly nearby genes associated with neuronal development. By in silico analysis, we found that 10 of these regions are located in loci which can potentially escape the first wave of genome‐wide demethylation after fertilization. In conclusion, human male germ cells present a unique germline‐specific ageing process, which likely results in diminished fecundity in elderly men and poorer health prognosis for their offspring.

Establishing the lower limits of total serum testosterone among Chinese proven fertile men who received treatment of assisted reproductive technology

Testosterone (T) plays a crucial role in spermatogenesis because extremely low levels of intratesticular T lead to correspondingly low serum levels of total T (tT), severe disorders of spermatogenesis, and male sterility. However, there is little consensus on the lower limits of serum tT in proven fertile men undergoing assisted reproductive technology treatments in Chinese or other Asian populations. We aimed to establish the reference range of serum tT based on a population of 868 fertile Chinese men undergoing in vitro fertilization or intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET) treatments. We defined a fertile man as having had a live baby with his partner as recorded in our IVF registration system. The lower limits of serum tT were established using a Siemens IMMULITE 2000 chemiluminescent system. The 1st, 2.5th, and 5th percentiles and their 95% confidence intervals (CIs) were 3.6 (95% CI: 2.7-4.1) nmol l-1, 4.3 (95% CI: 4.1-5.0) nmol l-1, and 5.6 (95% CI: 4.8-5.8) nmol l-1, respectively. Using the linear correlation of serum tT between the Siemens platform and a liquid chromatography-tandem mass spectrometry platform, the calculated lower limits of serum tT were also established for fertile Chinese men undergoing IVF/ICSI-ET treatments, which will benefit the clinical diagnosis and treatment of male infertility during such procedures.

Male hypogonadism: a review

This article contains a systematic review of the main developments that have occurred in the area of male hypogonadism between the publication of the Endocrine Society Guidelines of 2010 and 2018 and after 2018.

Late-onset hypogonadism: a concept comes of age

The term Late-onset hypogonadism (LOH) was coined in 2002 and defined as a disease entity in the ISA, ISSAM, EAU, EAA and ASA endorsed Recommendations for Investigation, Treatment and Monitoring of LOH (2005 and 2008) as 'a clinical and biochemical syndrome associated with advancing age, characterized by symptoms and a deficiency in serum testosterone (T)'. LOH was classified as a combined primary and secondary hypogonadism since the endocrine capacity of the testes and the pituitary are impaired. Symptoms of LOH include loss of libido, erectile dysfunction, loss of muscle mass, increased body fat, anemia, osteoporosis, depressed mood, decreased vitality, sweating, and hot flushes. Since these symptoms may also have origins other than LOH, exclusion of other disease entities and subnormal serum T levels are considered prerequisites for the diagnosis and possible treatment of LOH. However, during following years these guidelines were often neglected and, especially in the USA, indiscriminate prescribing of T was widely practised so that the US FDA warned against such irresponsible behavior. In Europe, T prescribing remained largely restricted to LOH as defined above. Nevertheless, a discussion started whether LOH really exists or is only a consequence of age-related comorbidities. Numerous studies have helped to clarify the situation, in particular, the European Male Aging Study (EMAS) and the US-initiated 7 T trials. Consequently, the newest US Endocrine Society Practice Guideline on T treatment (2018) includes advanced age as a cause of organic hypogonadism and recommends that 'in men >65 years who have symptoms or conditions suggestive of T deficiency … and consistently and unequivocally low morning T concentrations we suggest that clinicians offer T therapy on an individualised basis after explicit discussion of the potential risks and benefits'. Thus, the concept of LOH as conceived two decades ago has weathered criticism and survived the times.

Insights into replicative senescence of human testicular peritubular cells

There is evidence for an age-related decline in male reproductive functions, yet how the human testis may age is not understood. Human testicular peritubular cells (HTPCs) transport sperm, contribute to the spermatogonial stem cell (SSC) niche and immune surveillance, and can be isolated and studied in vitro. Consequences of replicative senescence of HTPCs were evaluated to gain partial insights into human testicular aging. To this end, early and advanced HTPC passages, in which replicative senescence was indicated by increased cell size, altered nuclear morphology, enhanced β-galactosidase activity, telomere attrition and reduced mitochondrial DNA (mtDNA), were compared. These alterations are typical for senescent cells, in general. To examine HTPC-specific changes, focused ion beam scanning electron microscopy (FIB/SEM) tomography was employed, which revealed a reduced mitochondrial network and an increased lysosome population. The results coincide with the data of a parallel proteomic analysis and indicate deranged proteostasis. The mRNA levels of typical contractility markers and growth factors, important for the SSC niche, were not significantly altered. A secretome analysis identified, however, elevated levels of macrophage migration inhibitory factor (MIF) and dipeptidyl peptidase 4 (DPP4), which may play a role in spermatogenesis. Testicular DPP4 may further represent a possible drug target.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Ageing in men with normal spermatogenesis alters spermatogonial dynamics and nuclear morphology in Sertoli cells

BACKGROUND

Ageing in men is believed to be associated with fertility decline and elevated risk of congenital disorders for the offspring. The previous studies also reported reduced germ and Sertoli cell numbers in older men. However, it is not clear whether ageing in men with normal spermatogenesis affects the testis and germ cell population dynamics in a way sufficient for transmitting adverse age effects to the offspring.

OBJECTIVES

We examined men with normal spermatogenesis at different ages concerning effects on persisting testicular cell types, that is the germ line and Sertoli cells, as these cell populations are prone to be exposed to age effects.

MATERIAL AND METHODS

Ageing was assessed in testicular biopsies of 32 patients assigned to three age groups: (i) 28.8 ± 2.7 years; (ii) 48.1 ± 1 years; and (iii) 70.9 ± 6.2 years, n = 8 each, with normal spermatogenesis according to the Bergmann-Kliesch score, and in a group of meiotic arrest patients (29.9 ± 3.8 years, n = 8) to decipher potential links between different germ cell types. Besides morphometry of seminiferous tubules and Sertoli cell nuclei, we investigated spermatogenic output/efficiency, and dynamics of spermatogonial populations via immunohistochemistry for MAGE A4, PCNA, CREM and quantified A-pale/A-dark spermatogonia.

RESULTS

We found a constant spermatogenic output (CREM-positive round spermatids) in all age groups studied. In men beyond their mid-40s (group 2), we detected increased nuclear and nucleolar size in Sertoli cells, indirectly indicating an elevated protein turnover. From the 7th decade (group 3) of life onwards, testes showed increased proliferation of undifferentiated spermatogonia, decreased spermatogenic efficiency and elevated numbers of proliferating A-dark spermatogonia.

DISCUSSION AND CONCLUSION

Maintaining normal sperm output seems to be an intrinsic determinant of spermatogenesis. Ageing appears to affect this output and might provoke compensatory proliferation increase in A spermatogonia which, in turn, might hamper germ cell integrity.

Temporal trends in sperm count: a systematic review and meta-regression analysis

BACKGROUND

Reported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality.

OBJECTIVE AND RATIONALE

To provide a systematic review and meta-regression analysis of recent trends in sperm counts as measured by sperm concentration (SC) and total sperm count (TSC), and their modification by fertility and geographic group.

SEARCH METHODS

PubMed/MEDLINE and EMBASE were searched for English language studies of human SC published in 1981-2013. Following a predefined protocol 7518 abstracts were screened and 2510 full articles reporting primary data on SC were reviewed. A total of 244 estimates of SC and TSC from 185 studies of 42 935 men who provided semen samples in 1973-2011 were extracted for meta-regression analysis, as well as information on years of sample collection and covariates [fertility group ('Unselected by fertility' versus 'Fertile'), geographic group ('Western', including North America, Europe Australia and New Zealand versus 'Other', including South America, Asia and Africa), age, ejaculation abstinence time, semen collection method, method of measuring SC and semen volume, exclusion criteria and indicators of completeness of covariate data]. The slopes of SC and TSC were estimated as functions of sample collection year using both simple linear regression and weighted meta-regression models and the latter were adjusted for pre-determined covariates and modification by fertility and geographic group. Assumptions were examined using multiple sensitivity analyses and nonlinear models.

OUTCOMES

SC declined significantly between 1973 and 2011 (slope in unadjusted simple regression models -0.70 million/ml/year; 95% CI: -0.72 to -0.69; P < 0.001; slope in adjusted meta-regression models = -0.64; -1.06 to -0.22; P = 0.003). The slopes in the meta-regression model were modified by fertility (P for interaction = 0.064) and geographic group (P for interaction = 0.027). There was a significant decline in SC between 1973 and 2011 among Unselected Western (-1.38; -2.02 to -0.74; P < 0.001) and among Fertile Western (-0.68; -1.31 to -0.05; P = 0.033), while no significant trends were seen among Unselected Other and Fertile Other. Among Unselected Western studies, the mean SC declined, on average, 1.4% per year with an overall decline of 52.4% between 1973 and 2011. Trends for TSC and SC were similar, with a steep decline among Unselected Western (-5.33 million/year, -7.56 to -3.11; P < 0.001), corresponding to an average decline in mean TSC of 1.6% per year and overall decline of 59.3%. Results changed minimally in multiple sensitivity analyses, and there was no statistical support for the use of a nonlinear model. In a model restricted to data post-1995, the slope both for SC and TSC among Unselected Western was similar to that for the entire period (-2.06 million/ml, -3.38 to -0.74; P = 0.004 and -8.12 million, -13.73 to -2.51, P = 0.006, respectively).

WIDER IMPLICATIONS

This comprehensive meta-regression analysis reports a significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011, driven by a 50-60% decline among men unselected by fertility from North America, Europe, Australia and New Zealand. Because of the significant public health implications of these results, research on the causes of this continuing decline is urgently needed.

Evidence for decreasing sperm count in African population from 1965 to 2015

PURPOSE

This meta-analysis, following our previous reports those documented an overall 57% diminution in mean sperm concentration around the globe over past 35 years and 32.5% decline in past 50 years in European population, attempts to report the declining trend of sperm concentrations in African population between 1965 and 2015.

METHODS

In the course of retrieval of data following MOOSE guidelines and PRISMA checklist, we found a total of fourteen studies that have been conducted during that period on altering sperm concentration in the African male.

RESULTS

Following analysis of the data, a time-dependent decline of sperm concentration (r = -0.597, p = 0.02) and an overall 72.6% decrease in mean sperm concentration was noted in the past 50 years. The major matter of concern is the present mean concentration (20.38×106/ml) is very near to WHO cut-off value of 2010 of 15×106/ml. Several epidemic diseases, genital tract infection, pesticides and heavy metal toxicity, regular consumption of tobacco and alcohol are reported as predominant causative factors.

CONCLUSION

This comprehensive, evidence-based meta-analysis and systematic review concisely presents the evidence of decreased sperm concentration in the African male over past 50 years with possible causative factors to serve the scientific research zone related to male reproductive health.

Decline in sperm count in European men during the past 50 years

Purpose:

To investigate whether the sperm concentration of European men is deteriorating over the past 50 years of time.

Materials and Methods:

We analysed the data published in English language articles in the past 50 years in altering sperm concentration in European men.

Results:

A time-dependent decline of sperm concentration ( r = −0.307, p = 0.02) in the last 50 years and an overall 32.5% decrease in mean sperm concentration was noted.

Conclusion:

This comprehensive, evidence-based meta-analysis concisely presents the evidence of decreased sperm concentration in European male over the past 50 years to serve the scientific research zone related to male reproductive health.

The relationship of salivary testosterone and male sexual dysfunction in opioid-associated androgen deficiency (OPIAD)

BACKGROUND

Opioids are an effective treatment for chronic non-malignant pain (CNP). Long-term use risks and side effects such as opioid-induced androgen deficiency (OPIAD) exist. This could be measured by saliva testosterone (Sal-T).

OBJECTIVES

To evaluate OPIAD in long-term opioid use in CNP patients.

METHODS

A cross-sectional study included CNP male outpatients under opioid treatment. Total-Testosterone (Total-T), Free-Testosterone (Free-T), Bio-Testosterone (Bio-T) and Sal-T were measured. Correlations were calculated by Spearman's rho (SPSS 20).

RESULTS

From 2012 to 2014, 134 from 249 (54%) consecutive male outpatients reported erectile dysfunction (ED), 37% of them related to opioids and 19% evidenced OPIAD. A total of 120 subjects (94 cases and 26 matched-controls) were included. A significantly lower luteinizing hormone, Total-T and Free-T were found, as well as, a significant correlation between Sal-T and Total-T (r = 0.234, p = 0.039), Bio-T (r = 0.241, p = 0.039), IIEF (r = 0.363, p = 0.003) and HAD-anxiety (r = -0.414, p = 0.012) in OPIAD patients. Sal-T levels were significantly lower in patients with severe-moderate ED versus mild ED (p = 0.045) and in patients with severe ED versus moderate-mild ED (p = 0.036).

CONCLUSIONS

These data demonstrate the high prevalence of ED in long-term use of opioids, part of this is associated to OPIAD, which can be tested by Sal-T as a non-invasive approach.

Adult-Onset Hypogonadism

In August 2015, an expert colloquium commissioned by the Sexual Medicine Society of North America (SMSNA) convened in Washington, DC, to discuss the common clinical scenario of men who present with low testosterone (T) and associated signs and symptoms accompanied by low or normal gonadotropin levels. This syndrome is not classical primary (testicular failure) or secondary (pituitary or hypothalamic failure) hypogonadism because it may have elements of both presentations. The panel designated this syndrome adult-onset hypogonadism (AOH) because it occurs commonly in middle-age and older men. The SMSNA is a not-for-profit society established in 1994 to promote, encourage, and support the highest standards of practice, research, education, and ethics in the study of human sexual function and dysfunction. The panel consisted of 17 experts in men's health, sexual medicine, urology, endocrinology, and methodology. Participants declared potential conflicts of interest and were SMSNA members and nonmembers. The panel deliberated regarding a diagnostic process to document signs and symptoms of AOH, the rationale for T therapy, and a monitoring protocol for T-treated patients. The evaluation and management of hypogonadal syndromes have been addressed in recent publications (ie, the Endocrine Society, the American Urological Association, and the International Society for Sexual Medicine). The primary purpose of this document was to support health care professionals in the development of a deeper understanding of AOH, particularly in how it differs from classical primary and secondary hypogonadism, and to provide a conceptual framework to guide its diagnosis, treatment, and follow-up.

The Disappearing Sperms: Analysis of Reports Published Between 1980 and 2015

Reports regarding the changes in sperm concentration in different counties of the world are inconsistent. Furthermore, the reports that sprung up from specific epidemiological and experimental examinations did not include data of prior studies or geographical variations. The current study, following a previous report of massive fall in semen volume over the past 33 years, attempts to delineate the trend of altering sperm concentrations and factors responsible for this by reviewing article published from 1980 to July 2015 with geographic differences. The current study identified an overall 57% diminution in mean sperm concentration over the past 35 years ( r = -.313, p = .0002), which, when analyzed for each geographical region, identified a significant decline in North America, Europe, Asia, and Africa. An increasing trend of sperm concentration was identified only in Australia. The association of male age with such a trend ( R² = .979) is reported. The authors also correlated male fertility with sperm concentration. Thus, this comprehensive, evidence-based literature review aims to concisely and systematically present the available data on sperm concentration from 1980 to 2015, as well as to statistically analyze the same and correlate male health with the declining pattern of sperm count in a single scientific review to serve the scientific research zone related to reproductive health. It points to the threat of male infertility in times ahead.

Apoptosome activation, an important molecular instigator in 6-mercaptopurine induced Leydig cell death

Leydig cells are crucial to the production of testosterone in males. It is unknown if the cancer chemotherapeutic drug, 6-mercaptopurine (6 MP), produces Leydig cell failure among adult survivors of childhood acute lymphoblastic leukemia. Moreover, it is not known whether Leydig cell failure is due to either a loss of cells or an impairment in their function. Herein, we show, in a subset of childhood cancer survivors, that Leydig cell failure is related to the dose of 6 MP. This was extended, in a murine model, to demonstrate that 6 MP exposure induced caspase 3 activation, and the loss of Leydig cells was independent of Bak and Bax activation. The death of these non-proliferating cells was triggered by 6 MP metabolism, requiring formation of both cytosolic reactive oxygen species and thiopurine nucleotide triphosphates. The thiopurine nucleotide triphosphates (with physiological amounts of dATP) uniquely activated the apoptosome. An ABC transporter (Abcc4/Mrp4) reduced the amount of thiopurines, thereby providing protection for Leydig cells. The studies reported here demonstrate that the apoptosome is uniquely activated by thiopurine nucleotides and suggest that 6 MP induced Leydig cell death is likely a cause of Leydig cell failure in some survivors of childhood cancer.

Testosterone therapy in older men with late-onset hypogonadism: a counter-rationale

OBJECTIVE

The past decade has seen a surge in referrals of older men for consideration of testosterone therapy for late-onset hypogonadism (LOH) to treat symptoms such as fatigue, sexual dysfunction and decreased vitality. Prescription sales of testosterone have accordingly increased by 20-fold over the same period, due mainly to marketing campaign as well as to the failure of clinicians to distinguish organic hypogonadism from LOH. This review seeks to provide a counter-rationale for testosterone therapy in LOH.

METHODS

A retrospective review of English-language epidemiologic studies, clinical trials and their relevant cited studies related to testosterone and older men was carried out.

RESULTS

Shortcomings of population studies on LOH include use of multiple numeric definitions and non-standard testosterone assays, and measurement of testosterone at a single time point. In contrast to higher estimates of prevalence based solely on numeric values, the syndromic prevalence of LOH is only 2%. Although attrition of testicular Leydig cells and slowing of gonadotropin-releasing hormone neurons both contribute to LOH, obesity and other comorbidities strongly influence testosterone levels, suggesting that testosterone is a biomarker of health. Testosterone therapy in LOH has consistently resulted in improvements in muscle mass and strength, although data regarding effects on physical function and improvements in fall and fracture rates remain unknown. Eythrocytosis is the most common adverse effect of testosterone therapy in older men, while long-term risks in the prostate and cardiovascular system remain unclear.

CONCLUSION

Considering the paucity of data on clinically meaningful outcomes, the number of uncertain risks, and the fact that modifiable risk factors adversely influence testosterone levels, healthy lifestyle and treatment of comorbidities might attenuate age-related declines in testosterone levels.

The effects of advanced paternal age on fertility

Modern societal pressures and expectations over the past several decades have resulted in the tendency for couples to delay conception. While women experience a notable decrease in oocyte production in their late thirties, the effect of age on spermatogenesis is less well described. While there are no known limits to the age at which men can father children, the effects of advanced paternal age are incompletely understood. This review summarizes the current state of knowledge regarding advanced paternal age and its implications on semen quality, reproductive success and offspring health. This review will serve as a guide to physicians in counseling men about the decision to delay paternity and the risks involved with conception later in life.

The conventional management of male infertility

Although the male reproductive function is impaired in about half of infertile couples, the evaluation of male infertility is underrated or neglected even today. In addition to a physical examination and imaging techniques, semen analysis as well as endocrine and genetic analyses should be part of the routine investigation. Few disorders have become subjects of rational treatment of the infertile male, even though, as examples, hypogonadotropic hypogonadism is treatable by gonadotropins and obstructive azoospermia by reconstructive surgery. Early treatment of maldescended testes and sexually transmitted diseases can prevent infertility. Similar pregnancy rates from patients with varicocele following surgery or counseling demonstrate the important role of the physician in the treatment of infertility. In the age of evidence-based medicine, most empirical treatments have been demonstrated to be ineffective. Instead, symptomatic treatment by assisted reproductive techniques has become a central tool to overcome otherwise untreatable male infertility.

Effects of age on male fertility

Later parenting is considered by many to have advantages, parents-to-be may feel themselves more stable to rear children. In addition, many men start a second family later in life. Thus, paternal age becomes an emerging issue. Aging affects male fertility by a scope of factors, which are not fully understood to date. Generally, the amount of produced sperm cells as well as their motility decreases with age, as testicular histological architecture deteriorates. Decreased fecundity and an increased risk for disturbed pregnancies occur with advancing paternal age. Some rare autosomal dominant pathologies are clearly related to paternal age. Altered patterns of epigenetics/gene expression in aging sperm seem to affect a range of neurocognitive disorders and also metabolic dyshomeostasis across generations. Such effects refer to men older than 40 years and may have impact on socio-economic issues. Nevertheless, councelling of older men seeking paternity should be patient-oriented and weigh statistical probabilities against the right for individual life-planning.

Changes in pituitary function with ageing and implications for patient care

The pituitary gland has a role in puberty, reproduction, stress-adaptive responses, sodium and water balance, uterine contractions, lactation, thyroid function, growth, body composition and skin pigmentation. Ageing is marked by initially subtle erosion of physiological signalling mechanisms, resulting in lower incremental secretory-burst amplitude, more disorderly patterns of pituitary hormone release and blunted 24 h rhythmic secretion. Almost all pituitary hormones are altered by ageing in humans, often in a manner dependent on sex, body composition, stress, comorbidity, intercurrent illness, medication use, physical frailty, caloric intake, immune status, level of exercise, and neurocognitive decline. The aim of this article is to critically discuss the mechanisms mediating clinical facets of changes in the hypothalamic-pituitary axis during ageing, and the extent to which confounding factors operate to obscure ageing-related effects.

Serum testosterone, dihydrotestosterone and estradiol concentrations in older men self-reporting very good health: the healthy man study

OBJECTIVE

To determine serum concentrations, intra-individual variability and impact of age-related co-morbidities on serum testosterone (T), dihydrotestosterone (DHT), estradiol (E(2)) and estrone (E(1)) in older men.

DESIGN

Observational, repeated measures study.

PARTICIPANTS

Men (n = 325) with 40 years and older self-reporting very good or excellent health.

MEASUREMENTS

Standardized history, physical examination and collection of nine blood samples at fixed time intervals were measured over 3 months (three at 20 min intervals on days 1 (fasting) and 2 (non-fasting), one at days 7, 30 and 90). Serum T, DHT, E(2) and E(1) (n = 2900, > 99% of scheduled samples) measured by liquid chromatography-tandem mass spectrometry (LC-MS) were analysed by linear mixed model analysis with fasting, age and obesity as covariables.

RESULTS

Mean serum T did not vary with age (P = 0·76) but obesity (-0·35 nM per body mass index (BMI) unit, P < 0·0001) and ex-smoker status (-1·6 nM, P < 0·001) had significant effects. Serum DHT was increased with age (+0·011 nM per year, P = 0·001) but decreased with obesity (-0·05 nM per BMI unit, P < 0·0001). Serum E(2) did not vary with age (P = 0·31) or obesity (P = 0·12). Overnight fasting increased (by 9-16%, all P < 0·001) and reduced variability in morning serum T, DHT, E(2) and E(1). Non-fasting serum T and DHT were stable over time (day, week, month or 3 months; P > 0·28).

CONCLUSIONS

Serum T, DHT and E(2) displayed no decrease associated with age among men over 40 years of age who self-report very good or excellent health although obesity and ex-smoking status were associated with decreased serum androgens (T and DHT) but not E(2). These findings support the interpretation that the age-related decline in blood T accompanying non-specific symptoms in older men may be due to accumulating age-related co-morbidities rather than a symptomatic androgen deficiency state.

Total testosterone may not decline with ageing in Korean men aged 40 years or older

OBJECTIVE

It is generally believed that gonadal function in men declines with ageing. However, observations on ageing-related decrease in total testosterone (TT) are not consistent. The aim of this study is to examine the ageing-related changes of testosterone and to investigate the influence of the ageing-related factors on TT.

DESIGN

Changes of TT with ageing were observed in longitudinal design in a single health promotion centre.

SUBJECTS

A total of 220 Korean men aged ≥40 years were included between 2002 and 2011. TT assay was repeated for all subjects, with an interval of ≥3 years.

MEASUREMENTS

Information of medical history and lifestyle habits was collected. Anthropometry and blood pressure were measured. TT, glucose, creatinine, highly sensitive C-reactive protein, liver enzymes and lipid profiles were tested.

RESULTS

Mean TT level did not decline significantly with ageing during median 4·3 years follow-up (18·1 vs 17·8 nm, P = 0·439). Longitudinal change of TT was approximately + 0·8% per year. TT was negatively correlated with body mass index (BMI), waist circumference and glucose. With mixed effects model, diabetes (P = 0·038) and BMI (P = 0·007) affected TT level, but age and follow-up interval did not.

CONCLUSIONS

TT did not change significantly in 220 Korean men for a median 4·3 years follow-up. TT was not influenced by the age and follow-up interval. BMI and diabetes mellitus affected TT decline.

Hormone replacement therapy and physical function in healthy older men. Time to talk hormones?

Improving physical function and mobility in a continuously expanding elderly population emerges as a high priority of medicine today. Muscle mass, strength/power, and maximal exercise capacity are major determinants of physical function, and all decline with aging. This contributes to the incidence of frailty and disability observed in older men. Furthermore, it facilitates the accumulation of body fat and development of insulin resistance. Muscle adaptation to exercise is strongly influenced by anabolic endocrine hormones and local load-sensitive autocrine/paracrine growth factors. GH, IGF-I, and testosterone (T) are directly involved in muscle adaptation to exercise because they promote muscle protein synthesis, whereas T and locally expressed IGF-I have been reported to activate muscle stem cells. Although exercise programs improve physical function, in the long-term most older men fail to comply. The GH/IGF-I axis and T levels decline markedly with aging, whereas accumulating evidence supports their indispensable role in maintaining physical function integrity. Several studies have reported that the administration of T improves lean body mass and maximal voluntary strength in healthy older men. On the other hand, most studies have shown that administration of GH alone failed to improve muscle strength despite amelioration of the detrimental somatic changes of aging. Both GH and T are anabolic agents that promote muscle protein synthesis and hypertrophy but work through separate mechanisms, and the combined administration of GH and T, albeit in only a few studies, has resulted in greater efficacy than either hormone alone. Although it is clear that this combined approach is effective, this review concludes that further studies are needed to assess the long-term efficacy and safety of combined hormone replacement therapy in older men before the medical rationale of prescribing hormone replacement therapy for combating the sarcopenia of aging can be established.

Advanced paternal age and reproductive outcome

Women have been increasingly delaying the start of motherhood in recent decades. The same trend is seen also for men. The influence of maternal age on fertility, chromosomal anomalies, pregnancy complications, and impaired perinatal and post-natal outcome of offspring, has been thoroughly investigated, and these aspects are clinically applied during fertility and pregestational counseling. Male aging and reproductive outcome has gained relatively less attention. The purpose of this review is to evaluate updated and relevant literature on the effect of paternal age on reproductive outcome.

Testosterone in older men after the Institute of Medicine Report: where do we go from here?

Despite nearly a half-century of research on aging and sex steroids in men, answers to key questions that would allow us to confidently assess risk:benefit ratios for androgen replacement in older men with the partial androgen deficiency of aging men (PADAM) syndrome remain uncertain. Although it is now reasonably clear that a significant percentage of otherwise healthy older men have decreases in testosterone and bioavailable testosterone to levels consistent with hypogonadism, the clinical implications of this change remain uncertain. Data suggest that low testosterone in older men is correlated to varying degrees with loss of lean body mass and muscle strength, and increased total and central body fat. Less certain, but suggestive, are data relating low testosterone levels to decreased bone density, loss of insulin sensitivity, and cognitive and affective deterioration, as well as reduced sexual function. Replacement of testosterone in older men has shown some positive effects on each of these variables, but findings have been inconsistent, perhaps because studies have employed different preparations and doses of androgens, treated for various durations, and defined their target populations in different ways. As important as beneficial effects is the potential for adverse effects, which may be greater in older men. Possible problems include sleep apnea, erythrocytosis, dyslipidemia with acceleration of atherosclerosis, and, of greatest concern, prostate cancer or hyperplasia. Studies to date have suggested that these outcomes are not major risks, but, in the absence of a large, randomized trial or trials, definitive information is not available. The US National Academies Institute of Medicine's recent report recommends that the National Institutes of Health support small efficacy trials aimed at treatment of androgen deficiency-related clinical conditions, but not a large, randomized trial to elucidate risk:benefit ratios. This recommendation, if adhered to, is likely to delay, rather than foster, progress in this important area.

Semen quality and age-specific changes: a study between two decades on 3,729 male partners of couples with normal sperm count and attending an andrology laboratory for infertility-related problems in an Indian city

OBJECTIVE

To compare the semen quality and age-specific changes in men between the 1980s and 2000s.

DESIGN

Prospective study.

SETTING

Andrology laboratory, University of Calcutta, India.

PATIENT(S)

A semen sample was obtained from 3729 men presenting for infertility problems in two distinct decades, that is, between 1981-85 and 2000-2006.

INTERVENTION(S)

Subjects with sperm count >20 x 10(6)/mL without any extreme pathological disorders were selected. Samples having a major liquefaction problem were excluded.

MAIN OUTCOME MEASURE(S)

A standard World Health Organization procedure for semen analysis was performed that included assessment of volume, sperm concentration, and percentage motility. The motility parameters were further classified into forward progressive motility and nonprogressive motility.

RESULT(S)

The present large-scale study confirms a significant decline in the sperm motility parameters and seminal volume in the present decade. However, no change in overall sperm concentration was noted. A decline was seen in sperm motility with increasing age in both decades.

CONCLUSION(S)

There are significant changes in sperm motility and volume between the two decades, and the age-related changes in semen parameters are also different in the two decades.