Association between male infertility and male-specific malignancies: systematic review and meta-analysis of population-based retrospective cohort studies

Interplay between male gonadal function and overall male health

The process-of-male reproduction is intricate, and various medical conditions-have the potential to disrupt spermatogenesis. Moreover, infertility in males can serve as an indicator of-potential future health issue. Numerous conditions with systemic implications have been identified, encompassing genetic factors (such as Klinefelter Syndrome), obesity, psychological stress, environmental factors, and others. Consequently, infertility assessment-presents an opportunity for comprehensive health counseling, extending-beyond discussions about reproductive goals. Furthermore, male infertility has been suggested as a harbinger of future health problems, as poor semen quality and a diagnosis of-male infertility are associated with an increased risk of hypogonadism, cardiometabolic disorders, cancer, and even mortality. This review explores the existing-literature on the relationship between systemic illnesses and male fertility, impacting both clinical-outcomes and semen parameters. The majority of the literature analyzed, which compared gonadal function with genetic, chronic, infectious or tumoral diseases, confirm the association between overall male health and infertility.

The Status of Spermatogenesis in Germ Cell Tumor Bearing Testis and Its Association with Metastatic Disease

INTRODUCTION

We aimed to evaluate the status of spermatogenesis detected by histological examination of non-tumoral testicular tissues in tumor bearing testis and its association with advanced stage disease.

PATIENTS AND METHODS

We retrospectively reviewed patients with testicular germ cell tumors (TGCTs) that undergone radical orchiectomy. All non-tumoral areas of the orchiectomy specimens were examined for the status of spermatogenesis. Patients were divided into two groups as localized (stage I) and metastatic (stage II-III) disease and analyzed separately for seminomatous (SGCT) and nonseminomatous germ cell tumors (NSGCT).

RESULTS

Four hundred fifty-four patients were included in our final analysis. Of those, 195 patients had SGCT, and 259 patients had NSGCT. Three hundred and six patients had localized disease at the time of diagnosis. Median (Q1-Q3) age was 31 (26 - 38) years and 102 (22.5%) patients had normal spermatogenesis, 177 (39.0%) patients had hypospermatogenesis and 175 (38.5%) patients had no mature spermatozoa. On multivariate logistic regression analysis, embryonal carcinoma >50% (1.944, 95 %CI 1.054-3.585, P = .033) and spermatogenesis status (2.796 95% CI 1.251-6.250, P = .012 for hypospermatogenesis, and 3.907, 95% CI 1.692-9.021, P = .001 for absence of mature spermatozoa) were independently associated with metastatic NSGCT. However, there was not any variables significantly associated with metastatic SGCT on multivariate logistic regression analysis.

CONCLUSION

Our study demonstrated that only 22.5% of patients with TGCTs had normal spermatogenesis in tumor bearing testis. Impaired spermatogenesis (hypospermatogenesis or no mature spermatozoa) and predominant embryonal carcinoma are associated with advanced stage NSGCT.

Time to pregnancy and life expectancy: a cohort study of 18 796 pregnant couples

STUDY QUESTION

Is fecundity, measured as time to pregnancy (TTP), associated with mortality in parents?

SUMMARY ANSWER

Prolonged TTP is associated with increased mortality in both mothers and fathers in a dose-response manner.

WHAT IS KNOWN ALREADY

Several studies have linked both male and female fecundity to mortality. In women, infertility has been linked to several diseases, but studies suggest that the underlying conditions, rather than infertility, increase mortality.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was carried out on 18 796 pregnant couples, in which the pregnant women attended prophylactic antenatal care between 1973 and 1987 at a primary and tertiary care unit. The couples were followed in Danish mortality registers from their child's birth date until death or until 2018. The follow-up period was up to 47 years, and there was complete follow-up until death, emigration or end of study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

At the first antenatal visit, the pregnant women were asked to report the time to the current pregnancy. Inclusion was restricted to the first pregnancy, and TTP was categorised into <12 months, ≥12 months, not planned, and not available. In sub-analyses, TTP ≥12 was further categorized into 12-35, 36-60, and >60 months. Information for parents was linked to several Danish nationwide health registries. Survival analysis was used to estimate the hazard ratios (HRs) with a 95% CI for survival and adjusted for age at the first attempt to become pregnant, year of birth, socioeconomic status, mother's smoking during pregnancy, and mother's BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

Mothers and fathers with TTP >60 months survived, respectively, 3.5 (95% CI: 2.6-4.3) and 2.7 (95% CI: 1.8-3.7) years shorter than parents with a TTP <12 months. The mortality was higher for fathers (HR: 1.21, 95% CI: 1.09-1.34) and mothers (HR: 1.29, 95% CI: 1.12-1.49) with TTP ≥12 months compared to parents with TTP <12 months. The risk of all-cause mortality during the study period increased in a dose-response manner with the highest adjusted HR of 1.98 (95% CI: 1.62-2.41) for fathers and 2.03 (95% CI: 1.56-2.63) for mothers with TTP >60 months. Prolonged TTP was associated with several different causes of death in both fathers and mothers, indicating that the underlying causes of the relation between fecundity and survival may be multi-factorial.

LIMITATIONS, REASONS FOR CAUTION

A limitation is that fecundity is measured using a pregnancy-based approach. Thus, the cohort is conditioned on fertility success and excludes sterile couples, unsuccessful attempts and spontaneous abortions. The question used to measure TTP when the pregnant woman was interviewed at her first attended prophylactic antenatal care: 'From the time you wanted a pregnancy until it occurred, how much time passed?' could potentially have led to serious misclassification if the woman did not answer on time starting unprotected intercourse but on the start of wishing to have a child.

WIDER IMPLICATIONS OF THE FINDINGS

We found that TTP is a strong marker of survival, contributing to the still-emerging evidence that fecundity in men and women reflects their health and survival potential.

STUDY FUNDING/COMPETING INTEREST(S)

The authors acknowledge an unrestricted grant from Ferring. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication. M.L.E. is an advisor to Ro, VSeat, Doveras, and Next.

TRIAL REGISTRATION NUMBER

N/A.

Antioxidant treatment for oligoasthenoteratozoospermia and varicocele: a DBPC trial to evaluate the impact of age and body mass index

ABSTRACT

Oxidative stress is one of the main mechanisms responsible for male infertility. Various conditions such as varicocele, obesity, advanced age, and lifestyle can lead to an increase in reactive oxygen species, causing an oxidative imbalance in the reproductive environment. Spermatozoa are sensitive to reactive oxygen species and require energy to carry out their main function of fertilizing the egg. Excessive reactive oxygen species can affect sperm metabolism, leading to immobility, impaired acrosome reaction, and cell death, thereby impairing reproductive success. This double-blind randomized study evaluated the effect of supplementation with L-carnitine, acetyl-L-carnitine, vitamins, and other nutrients on semen quality in 104 infertile patients with or without varicocele, while also investigating the impact of factors such as obesity and advanced age on treatment. Sperm concentration significantly increased in the supplemented group compared to the placebo group (P = 0.0186). Total sperm count also significantly increased in the supplemented group (P = 0.0117), as did sperm motility (P = 0.0120). The treatment had a positive effect on patients up to 35 years of age in terms of sperm concentration (P = 0.0352), while a body mass index (BMI) above 25 kg m-2 had a negative effect on sperm concentration (P = 0.0110). Results were not showing a net benefit in stratifying patients in accordance with their BMI since sperm quality increase was not affected by this parameter. In conclusion, antioxidant supplementation may be beneficial for infertile patients and has a more positive effect on younger patients with a normal weight.

Frequency, morbidity and equity - the case for increased research on male fertility

Currently, most men with infertility cannot be given an aetiology, which reflects a lack of knowledge around gamete production and how it is affected by genetics and the environment. A failure to recognize the burden of male infertility and its potential as a biomarker for systemic illness exists. The absence of such knowledge results in patients generally being treated as a uniform group, for whom the strategy is to bypass the causality using medically assisted reproduction (MAR) techniques. In doing so, opportunities to prevent co-morbidity are missed and the burden of MAR is shifted to the woman. To advance understanding of men's reproductive health, longitudinal and multi-national centres for data and sample collection are essential. Such programmes must enable an integrated view of the consequences of genetics, epigenetics and environmental factors on fertility and offspring health. Definition and possible amelioration of the consequences of MAR for conceived children are needed. Inherent in this statement is the necessity to promote fertility restoration and/or use the least invasive MAR strategy available. To achieve this aim, protocols must be rigorously tested and the move towards personalized medicine encouraged. Equally, education of the public, governments and clinicians on the frequency and consequences of infertility is needed. Health options, including male contraceptives, must be expanded, and the opportunities encompassed in such investment understood. The pressing questions related to male reproductive health, spanning the spectrum of andrology are identified in the Expert Recommendation.

The Immune Landscape and Immunotherapeutic Strategies in Platinum-Refractory Testicular Germ Cell Tumors

Testicular germ cell tumors (TGCTs) are cancers with very good prognosis, even in the metastatic setting, with high curative potential mainly attributed to the introduction of cisplatin-based chemotherapy. However, approximately 15% of the patients develop platinum-refractory disease and suffer multiple relapses. Therefore, there is an unmet need for novel therapeutic agents with improved efficacy and minimal long-term side effects. Recent advances in the development of immunotherapeutic agents, particularly immune checkpoint inhibitors (ICIs), have offered an opportunity to test their activity in various tumor types, including GCTs. This review aims to analyze the immune microenvironment of these tumors and present the most recently available data from studies that have tested immunotherapeutic agents against GCTs. The majority of the available knowledge derives from case reports or small cohort studies, particularly those involving ICIs of the PD-1/PD-L1 axis alone or in combination with anti-CTLA-4 monoclonal antibodies. Other immunotherapeutic targeted approaches, including antibody-drug conjugates, antibody prodrugs, vaccines, tyrosine kinase inhibitors, chimeric antigen receptor (CAR) T-cell therapy, have biological rationales and have shown preliminary activity or are currently being tested. Growing evidence on these and other approaches will assist in broadening the currently limited treatment armamentarium against platinum-refractory TGCTs.

Reproduction as a window for health in men

Male factor infertility is widely considered a harbinger for a man's general health. Failure of reproduction often accompanies other underlying processes, with growing evidence suggesting that a diagnosis of infertility increases the likelihood of developing future cardiac, metabolic, and oncologic diseases. The goal of this review is to provide a comprehensive overview of the research on male fertility as a marker for current and future health. A multidisciplinary approach is essential, and there is growing consensus that the male fertility evaluation offers an opportunity to better men's wellness beyond their immediate reproductive ambitions.

2022 Update on Prostate Cancer Epidemiology and Risk Factors-A Systematic Review

CONTEXT

Prostate cancer (PCa) is one of the most common cancers worldwide. Understanding the epidemiology and risk factors of the disease is paramount to improve primary and secondary prevention strategies.

OBJECTIVE

To systematically review and summarize the current evidence on the descriptive epidemiology, large screening studies, diagnostic techniques, and risk factors of PCa.

EVIDENCE ACQUISITION

PCa incidence and mortality rates for 2020 were obtained from the GLOBOCAN database of the International Agency for Research on Cancer. A systematic search was performed in July 2022 using PubMed/MEDLINE and EMBASE biomedical databases. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and was registered in PROSPERO (CRD42022359728).

EVIDENCE SYNTHESIS

Globally, PCa is the second most common cancer, with the highest incidence in North and South America, Europe, Australia, and the Caribbean. Risk factors include age, family history, and genetic predisposition. Additional factors may include smoking, diet, physical activity, specific medications, and occupational factors. As PCa screening has become more accepted, newer approaches such as magnetic resonance imaging (MRI) and biomarkers have been implemented to identify patients who are likely to harbor significant tumors. Limitations of this review include the evidence being derived from meta-analyses of mostly retrospective studies.

CONCLUSIONS

PCa remains the second most common cancer among men worldwide. PCa screening is gaining acceptance and will likely reduce PCa mortality at the cost of overdiagnosis and overtreatment. Increasing use of MRI and biomarkers for the detection of PCa may mitigate some of the negative consequences of screening.

PATIENT SUMMARY

Prostate cancer (PCa) remains the second most common cancer among men, and screening for PCa is likely to increase in the future. Improved diagnostic techniques can help reduce the number of men who need to be diagnosed and treated to save one life. Avoidable risk factors for PCa may include factors such as smoking, diet, physical activity, specific medications, and certain occupations.

Onco-TESE (Testicular Sperm Extraction): Insights from a Tertiary Center and Comprehensive Literature Analysis

Background and Objectives: The peak of incidence of testicular cancer (TC) occurs among individuals in their reproductive age, emphasizing the importance of fertility preservation as an integral aspect of disease management. Sperm cryopreservation performed before orchiectomy is ineffective in azoospermic men, necessitating alternative approaches such as microdissection testicular sperm extraction (mTESE) at the time of orchiectomy (onco-mTESE) to obtain viable sperm. This study presents the findings from our institution's experience with onco-mTESE and critically discusses our results in light of the existing body of literature. Materials and Methods: This is a tertiary center retrospective analysis of onco-mTESE procedures performed at a single center between December 2011 and July 2022. The included patients were post-puberal men with testicular tumors requiring orchiectomy, along with concomitant severe oligozoospermia or azoospermia. Bilateral mTESE was performed in all cases. Surgical outcomes, sperm retrieval rates, the usage of preserved viable sperm, assistive reproductive techniques' results, and post-operative serum testosterone were recorded. Results: A total of nine patients were included, with a median age of 34 (IQR 29-36) years. All patients had germ cell tumors (GCTs), with seminomatous and non-seminomatous GCTs accounting for 44.4% (n = 4) and 55.6% (n = 5) of patients, respectively. Sperm retrieval occurred in three (33%) patients: one patient in the ipsilateral testis, one in the contralateral testis, and one in both testes. No complications were reported during the procedure, and no post-operative hypogonadism was observed. Among the three patients with successful sperm retrieval, an intracytoplasmic sperm injection (ICSI) was performed in two patients, resulting in two pregnancies, leading to one healthy live birth and one miscarriage. Conclusions: In the context of TC, it is essential to conduct a thorough evaluation of testicular function, including a semen analysis and cryopreservation. Onco-mTESE has proven its safety in preserving fertility in azoospermic cases while ensuring the efficacy of oncological treatment.

Semen Analysis in "Urology-Naïve" Patients: A Chance of Uroandrological Screening in Young Males

(1) Background: While females start their gynecological examinations during puberty, only few men decide to be visited by urologists in their youth. Given the participation in the EcoFoodFertility research project, our department had the opportunity to screen young males that were supposedly healthy. (2) Results: from January 2019 to July 2020, we evaluated 157 patients with sperm, blood analysis, and uroandrological examinations. The inclusion criteria were age 18-40 and absence of previous urological disease (urology-naïve). The primary endpoint of the study was to record uroandrological diseases that are occasionally discovered during examination in asymptomatic young men. The average age was 26.9 years (range 18-40); average testicular volume was 15.7 mL (range 12-22 mL); and 45.2% reported abnormal semen analysis: 62 cases of teratozoospermia, 27 asthenozoospermia, 18 oligozoospermia, and 2 azoospermia were discovered respectively; 4/157 patients were diagnosed with hypogonadism; 2 cases with suspicious testicular mass resulted in testicular cancer; and 31 suspected varicoceles and 8 patients with mild sexual dysfunctions were managed. (3) Conclusions: an uroandrological evaluation of young asymptomatic males allowed for the prompt diagnosis of different urological conditions, including cancerous ones, in our series. Despite being debatable, combining urological counselling with physical examination, semen analysis, and a laboratory profile could be useful and cost-effective in order to ameliorate male health.

Isochromosome 12p Formation Regulates Vitamin D Metabolism in Testicular Cancer

Isochromosome 12p (iChr12p) is typical in almost all invasive testicular cancers. Increased copy number of genes on 12p is associated with the development of a clinically manifest tumor; however, the causative genes have not yet been identified. Chromosome 12 harbors many genes involved in Vitamin D metabolism. RNAseq analysis of Vitamin D receptor (VDR) genes from the TCGA cohort revealed that clustering of VDR expression signatures could differentiate between pure seminomas and non-seminomatous germ cell tumors (NSGCT). Using TCGA mRNA expression of anabolic (CYP2R1, CYP27A1 and CYP27B1) and catabolic (CYP24A1) Vitamin D enzymes, positive (PTHLH, IFNG, and TNF) and negative (FGF23) feedback regulators could also clearly distinguish between pure seminomas and NSGCT. We hypothesize that the regulation of Vitamin D metabolism might be disturbed through iChr12p formation, influencing testicular carcinogenesis via increased FGF23 and PTHLH expression. While FGF23 represses CYP27B1 and activates catabolism of active hormone, increased PTHLH secretion can lead to hypercalcemia via inactivation of VDR. In conclusion, testicular cancer is associated with extensive modifications in intratesticular Vitamin D homeostasis. Further research is needed to clarify whether Vitamin D deficiency causes the formation of iChr12p and whether Vitamin D deficiency via iChr12p genomic aberration is involved in testicular carcinogenesis.

Efficacy of Different Bacillus of Calmette-Guérin (BCG) Strains on Recurrence Rates among Intermediate/High-Risk Non-Muscle Invasive Bladder Cancers (NMIBCs): Single-Arm Study Systematic Review, Cumulative and Network Meta-Analysis

BACKGROUND

In an era of Bacillus of Calmette-Guérin (BCG) shortages, the comparative efficacy from different adjuvant intravesical BCG strains in non-muscle invasive bladder cancer (NMIBC) has not been clearly elucidated. We aim to compare, through a systematic review and meta-analysis, the cumulative BC recurrence rates and the best efficacy profile of worldwide available BCG strains over the last forty years.

METHODS

PubMed, Scopus, Web of Science, Embase, and Cochrane databases were searched from 1982 up to 2022. A meta-analysis of pooled BC recurrence rates was stratified for studies with ≤3-y vs. >3-y recurrence-free survival (RFS) endpoints and the strain of BCG. Sensitivity analysis, sub-group analysis, and meta-regression were implemented to investigate the contribution of moderators to heterogeneity. A random-effect network meta-analysis was performed to compare BCG strains on a multi-treatment level.

RESULTS

In total, n = 62 series with n = 15,412 patients in n = 100 study arms and n = 10 different BCG strains were reviewed. BCG Tokyo 172 exhibited the lowest pooled BC recurrence rate among studies with ≤3-y RFS (0.22 (95%CI 0.16-0.28). No clinically relevant difference was noted among strains at >3-y RFS outcomes. Sub-group and meta-regression analyses highlighted the influence of NMIBC risk-group classification and previous intravesical treated categories. Out of the n = 11 studies with n = 7 BCG strains included in the network, BCG RIVM, Tice, and Tokyo 172 presented with the best-predicted probability for efficacy, yet no single strain was significantly superior to another in preventing BC recurrence risk.

CONCLUSION

We did not identify a BCG stain providing a clinically significant lower BC recurrence rate. While these findings might discourage investment in future head-to-head randomized comparison, we were, however, able to highlight some potential enhanced benefits from the genetically different BCG RIVM, Tice, and Tokyo 172. This evidence would support the use of such strains for future BCG trials in NMIBCs.

Male infertility and somatic health - insights into lipid damage as a mechanistic link

Over the past decade, mounting evidence has shown an alarming association between male subfertility and poor somatic health, with substantial evidence supporting the increased incidence of oncological disease, cardiovascular disease, metabolic disorders and autoimmune diseases in men who have previously received a subfertility diagnosis. This paradigm is concerning, but might also provide a novel window for a crucial health reform in which the infertile phenotype could serve as an indication of potential pathological conditions. One of the major limiting factors in this association is the poor understanding of the molecular features that link infertility with comorbidities across the life course. Enzymes involved in the lipid oxidation process might provide novel clues to reconcile the mechanistic basis of infertility with incident pathological conditions. Building research capacity in this area is essential to enhance the early detection of disease states and provide crucial information about the disease risk of offspring conceived through assisted reproduction.

Mediterranean diet and infertility: a systematic review with meta-analysis of cohort studies

Context

The Mediterranean diet (MD) is a dietary pattern with evidence of positive health impact, and some nutrients in this diet have already been researched for their effectiveness in fertility. However, there are still questions about whether high adherence to the MD could be a factor that contributes to positive fertility outcomes in infertile men and women.

Objective

A systematic review and meta-analysis were conducted to determine whether a greater adherence to the MD can improve fertility markers and outcomes in infertile men and women.

Data sources

The MEDLINE, BVS, SciELO, CENTRAL, and Embase databases and gray literature were searched from their inception to May 2022.

Study selection

Data were included from cohort studies that addressed MD and outcomes.

Data extraction

Data searches, article selection, data extraction, and risk-of-bias assessments were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

A total of 11 studies met the inclusion criteria (n = 13 157 women and 1338 men). Greater adherence to the MD was associated with live births (I2 = 83.16%; odds ratio [OR], 0.652; 95%CI, 0.408–3.194), pregnancy rate (I2 = 93.83%; OR, 1.192; 95%CI, 0.349–4.325), sperm concentration &gt;15 × 106/mL (I2 = 32.97%; OR 2.862; 95%CI, 1.583–5.174), and sperm count &gt; 39 × 106/mL (I2 = 48.1%; OR, 2.543; 95%CI, 1.319–4.904); however, in an inconsistent scenario regarding the meta-analysis.

Conclusion

Current evidence of high adherence to MD and fertility markers is insufficient to support their clinical application, even though it indicates sperm improvement and a possibility of better pregnancy outcomes.

Systematic Review Registration

PROSPERO registration no. 169396.

Male infertility: what on earth is going on? Pilot international questionnaire study regarding clinical evaluation and fertility treatment for men

Infertility is a time-consuming and exhaustive process, which disproportionally affects women. Although concerns have been raised about deficiencies in clinical evaluation of infertile men, there is currently little published data documenting this. A SurveyMonkey questionnaire was therefore created to capture current clinical practice of fertility specialists working in IVF clinics. Responses were collected May - July 2021. 112 clinicians completed the pilot survey with respondents from Europe (n=49; 43.8%), Africa (n=39, 34.8%), North America (n=6; 5.4%), Asia (n=16; 14.3%), South America (n=1; 0.9%) and Australasia (n=1;0.9%). 41% fertility specialists (45/110) reported taking only a brief medical history and 24% reported that they never routinely examined infertile male patients. 54% fertility specialists also reported issues getting men to undertake diagnostic semen analysis. Treatment for male infertility spanned Assisted Reproductive Technology (ART), with themes of individualised medicine influencing treatment recommendations. 48.2% clinicians reported using empirical medical therapy (EMT) for unexplained male infertility. Notably, 3.6% respondents recommended testosterone treatment, despite likely negative impact on spermatogenesis. However, high levels of opportunistic general health advice were reported, including discussion of life exposures thought to be important for male reproductive health. This study adds novel evidence and highlights current deficiencies in clinical practice relating to male infertility. Evaluation of the infertile male using simple medical tools (detailed history taking and clinical examination) has the potential to identify treatable or reversible conditions and should be an immediate focus for education and improvement in Reproductive Medicine. Investment in research and development is much needed in the field of andrology, to develop effective non-ART treatment options for male infertility.

Can Diet Prevent Urological Cancers? An Update on Carotenoids as Chemopreventive Agents

Urological cancers, namely prostate, bladder, kidney, testicular, and penile cancers, are common conditions that constitute almost one-quarter of all malignant diseases in men. Urological cancers tend to affect older individuals, and their development is influenced by modifiable metabolic, behavioral, and environmental risk factors. Phytochemicals may have cancer-fighting properties and protect against cancer development, slow its spread, and reduce the risk of cancer deaths in humans. This paper aims to review the current literature in regard to the effects of carotenoids in reducing urological cancer risk.

A Systematic Review and Meta-Analysis of Male Infertility and the Subsequent Risk of Cancer

Objectives

The primary objective of this systemic review and meta-analysis was to investigate the risk of developing composite outcome of all cancers, regardless of the type of cancer among men with infertility diagnosis compared to fertile counterparts. The secondary objective was to compare the pooled risk of developing individual specific cancers between two groups.

Methods

A systematic literature search was performed on the databases of PubMed (including Medline), Scopus, and Web of Science to retrieve observational studies published in English language from 01.01.1990 to 28. 02. 2021. They assessed cancer events in males with an infertility diagnosis compared to controls without infertility. The outcomes of interest were a composite outcome of cancers including all known cancer types, and also specific individual cancers. The fixed/random effects model was used to analyze heterogeneous and non-heterogeneous results. Publication bias was assessed using the Harbord test, Egger test, Begg test, and funnel plot. The pooled odds ratio of cancers was calculated using the DerSimonian and Laird, and inverse variance methods. Studies’ quality and risk of bias were assessed using structured standard tools.

Results

We included eight cohort studies involving 168,327 men with the diagnosis of infertility and 2,252,806 men without it. The total number of composite outcome of cancers as well as individual cancers including prostate, testicular and melanoma were 1551, 324, 183 and 121 in the infertile men and 12164, 3875, 849, and 450 in the fertile men, respectively. The pooled OR of the composite outcome of cancers, regardless of the type of cancer, in men with infertility was 1.4 folds higher than those without infertility (pooled OR = 1.43, 95% confidence interval [CI]: 1.25-1.64). Meta-analysis of individual cancers including prostate, testicular and melanoma between two groups was carried out. The pooled ORs of testicular and prostate cancers in men with the diagnosis of infertility were significantly higher than controls without infertility (pooled OR = 1.91, 95% CI: 1.52-2.42 and pooled OR = 1.48, 95% CI: 1.05-2.08, respectively). Additionally, the pooled OR of melanoma in men with infertility was 1.3 folds higher than those without infertility (pooled OR = 1.31, 95% CI: 1.06-1.62).

Conclusion

A greater risk of cancers in men with male infertility was found suggesting that the history of male infertility might be an important risk factor for developing cancers in later life. Further well-designed long-term population-based prospective studies, considering all known cancers and their accompanying risk factors should be conducted to support our findings.

Male fertility as a marker for health

Male reproduction is a complex biological process, and male factor infertility is increasingly recognized as a biomarker for overall male health. Emerging data suggest associations between male reproduction and medical disease (genetic, infectious, chronic comorbid conditions), psychological disease, environmental exposures, dietary habits, medications and substances of abuse, and even socioeconomic factors. There is also evidence that a diagnosis of male fertility is associated with future disease risk including cancer, metabolic disease and mortality. As such, there is a growing view that the male fertility evaluation is an opportunity to improve a man's health beyond his immediate reproductive goals, and also highlights the necessity of a multidisciplinary approach.

Impaired fecundity as a marker of health and survival: a Danish twin cohort study

STUDY QUESTION

Is fecundity, measured as self-reported time to first pregnancy (TTP), a marker for subsequent health and survival?

SUMMARY ANSWER

Long TTP was a marker for increased mortality among women and higher hospitalization rates for both women and men.

WHAT IS KNOWN ALREADY

Poor semen quality has been linked to increased mortality and morbidity from a wide range of diseases. Associations among fecundity, health and survival among women are still uncertain and studies on actual measures of fecundity and health outcomes are rare.

STUDY DESIGN, SIZE, DURATION

We performed a prospective cohort study of 7825 women and 6279 men, aged 18 and above with measures on first TTP, who participated in one of the Danish nation-wide twin surveys in 1994 (twins born 1953-1976) and 1998 (twins born 1931-1952). They were followed-up for mortality and hospital admissions from the interview until 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Twins were identified in the Danish Twin Registry and linked to Danish registers. TTP was restricted to the first pregnancy as a categorical outcome with cut-off points at 2, 10 and 18 months. We analysed the association between TTP and survival using a Cox proportional hazards model estimating hazards ratios (HRs) with 95% confidence intervals (CIs). Fine-Gray survival models were used to estimate sub-hazard ratios for specific causes of death allowing for competing risks. Using negative binomial regression, we estimated incidence rate ratios (IRRs) with 95% CIs for all-cause and cause-specific hospitalizations. All analyses were stratified by sex and adjusted for age at interview, birth cohorts, age at first attempt to become pregnant, smoking, years in school and BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

In the total study population, 49.9% of women and 52.7% of men reported a TTP of less than 2 months, 30.8% of women and 29.6% of men reported a TTP of 2-9 months, 6.6% of women and 5.7% of men reported a TTP of 10-17 months, and 13.3% of women and 12.0% of men reported a TTP of 18 months or more. Among 1305 deaths, we found a higher mortality for women (HR = 1.46; 95% CI 1.15, 1.87) with a TTP of ≥18 months relative to those with a TTP of <2 months, while the highest mortality was indicated for men with a TTP of 10-17 months (HR = 1.31; 95% CI 0.98, 1.74). Among 53 799 hospitalizations, we found an increased hospitalization rate among women (HR = 1.21; 95% CI 1.0-1.41) and men (HR = 1.16; 95% CI 1.00-1.35) with a TTP of ≥18 months, and for men with a TTP of 2-9 months (HR = 1.14; 95% CI 1.01-1.30). A dose-response relationship was found for women regarding both mortality (P = 0.022) and hospitalizations (P = 0.018). Impaired fecundity was associated with a wide range of diseases and some causes of death, indicating a multi-factorial causal influence on fecundity, especially among women.

LIMITATIONS, REASONS FOR CAUTION

A major limitation was that fecundity depends on both partners, which was not considered in this study. Moreover, we could not obtain information on a number of potential confounders.

WIDER IMPLICATIONS OF THE FINDINGS

Fecundity seems positively correlated with overall health and may be a universal marker of future health and survival. These results add knowledge to the limited findings showing that reduced fecundity in women and poor semen quality in men may reflect worse health and a shorter life, particularly among women.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by NIH grant HD096468 (M.L.E., T.K.J. and R.L.J.). The authors declare that they have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Association between male infertility and prostate cancer: a systematic review and meta-analysis

PURPOSE OF REVIEW

Male infertility has been shown to be associated with different maladies. The present systematic review and meta-analysis aimed to summarize the available evidence on the association between male infertility or childlessness and prostate cancer.

RECENT FINDINGS

The PubMed, Web of Science, and Scopus databases were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Studies were deemed eligible if they compared males with known infertility or childlessness to the control group including fertile males with regards to the diagnosis of prostate cancer. Overall, ten studies met our eligibility criteria. Three studies found that infertility was associated with higher risk of prostate cancer, four studies - with a reduced risk of prostate cancer, and three studies found no association. The forest plot revealed that infertility was not associated with prostate cancer (odds ratio [OR]: 1.26, 95% confidence interval [CI] 0.63-2.54; P = 0.5). Infertility was not associated with high (OR: 1.44, 95% CI 0.54-3.83; P = 0.5) or low (OR: 0.99, 95% CI 0.43-2.27; P = 0.9) grade prostate cancer.

SUMMARY

Infertility or childlessness were not associated with the risk of prostate cancer. The significant heterogeneity between the included studies supports the need for more granular research to guide/fine tune early detection guidelines based on fertility.

The Association between Mortality and Male Infertility: Systematic Review and Meta-analysis

OBJECTIVE

To summarize the current body of evidence on the relationship between impaired male fertility and the risk of early death through a systematic review and meta-analysis of population-based retrospective cohort studies.

METHODS

PubMed, Web of Science, Embase, Cochrane Library, and Scopus databases were searched from inception to August 2020 according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. Pooled Risk Ratio (RR), Risk Difference (Δr), Hazard Ratio (HR) and Standardized Mortality Ratio (SMR) differences among male factor infertility cohorts were compared to fertile/normospermic control populations or to national mortality data.

RESULTS

Six studies from 2006 to 2020 met inclusion criteria. Three studies examined male infertility and mortality (n_tot = 202,456; n_deaths = 1396), while four studies examined survival in relation to semen parameters (n_tot = 59,291; n_deaths = 643). Comparing infertile to fertile men, pooled HR for the risk of death was 1.26 (95%CI:1.01-1.59). Pooled RR and Δr of death for combined oligo- and azoospermic men vs normospermic men was 1.67 (95%CI:1.26-2.21) and 0.37% (95%CI:0.18-0.55%) respectively. When comparing oligo- and normospermic men to azoospermic men, the cumulative HR was 1.31 (95%CI:1.11-1.54) and 2.17 (95%CI:1.55-3.04) respectively. Infertile men had a lower overall risk of death compared to the overall population (SMR, 0.38, 95%CI:0.31-0.45).

CONCLUSION

Compared to fertile men, infertile men had a higher risk of death. Moreover, the risk of death increased with increasing severity of semen quality impairment. However, compared to men from the general population, infertile men have a lower risk of death suggesting that social determinants of health are also important.

Male Infertility Knowledgebase: decoding the genetic and disease landscape

Male infertility is a multifactorial condition that contributes to around one-third of cases of infertility worldwide. Several chromosomal aberrations, single-gene and polygenic associations with male factor defects have been reported. These defects manifest as sperm number or sperm quality defects leading to infertility. However, in almost 40% of cases, the genetic etiology of male infertility remains unexplained. Understanding the causal genetic factors is crucial for effective patient management and counseling. Integrating the vast amount of available omics data on male infertility is a first step towards understanding, delineating and prioritizing genes associated with the different male reproductive disorders. The Male Infertility Knowledgebase (MIK) is a manually curated repository developed to boost research on the elusive genetic etiology of male infertility. It integrates information on ∼17 000 genes, their associated pathways, gene ontology, diseases and gene and sequence-based analysis tools. In addition, it also incorporates information on reported chromosomal aberrations and syndromic associations with male infertility. Disease enrichment of genes in MIK indicate a shared genetic etiology between cancer, male and female infertility disorders. While the genes involved in cancer pathways were found to be common causal factors for sperm number and sperm quality defects, the interleukin pathways were found to be shared and enriched between male factor defects and non-reproductive conditions like cardiovascular diseases, metabolic diseases, etc. Disease information in MIK can be explored further to identify high-risk conditions associated with male infertility and delineate shared genetic etiology. Utility of the knowledgebase in predicting novel genes is illustrated by identification of 149 novel candidates for cryptorchidism using gene prioritization and network analysis. MIK will serve as a platform for review of genetic information on male infertility, identification pleiotropic genes, prediction of novel candidate genes for the different male infertility diseases and for portending future high-risk diseases associated with male infertility.

Database URL: http://mik.bicnirrh.res.in/

Modeling the contribution of the obesity epidemic to the temporal decline in sperm counts

OBJECTIVE

Total sperm count (TSC) has been declining worldwide over the last several decades due to unknown etiologies. Our aim was to model the contribution that the obesity epidemic may have on declining TSC.

MATERIALS AND METHODS

Obesity rates were determined since 1973 using the WHO's Global Health Observatory data. A literature review was performed to determine the association between TSC and obesity. Using the measured obesity rates and published TSC since 1973, a model was created to evaluate the association between temporal trends in obesity/temperature and sperm count.

RESULTS

Since 1973, obesity prevalence in the United States was increased from 41% to 67.9%. A review of the literature showed that body mass index (BMI) categories 2, 3, and 4 were associated with TSC (millions) of 164.27, 155.71, and 142.29, respectively. The contribution to change over time for obesity from 1974 to 2011 was modeled at 1.8%. When the model was changed to represent the most extreme possible contribution to obesity reported, the modeled change over time rose to 7.2%. When stratified according to fertility status, the contribution that BMI had to falling sperm counts for all comers was 1.7%, while those presenting for fertility evaluation was 2.1%.

CONCLUSIONS

While the decline in TSC may be partially due to rising obesity rates, these contributions are minimal which highlights the complexity of this problem.

Increased Mortality Among Men Diagnosed With Impaired Fertility: Analysis of US Claims Data

OBJECTIVE

To determine whether male infertility or impaired spermatogenesis is associated with mortality.

METHODS

The Optum de-identified Clinformatics Data Mart database was queried from 2003 to 2017. Infertile men were compared to subjects undergoing semen analysis (ie, infertility testing). Infertile men with oligozoospermia or azoospermia were included. Mortality was determined by data linkage to the Social Security Administration Death Master File. Results were adjusted for age, smoking, obesity, year of evaluation, and health care visits as well as for most prevalent comorbidities. We separately examined men with prevalent or incident cardiovascular disease and cancer diagnoses to determine associations with mortality.

RESULTS

A total of 134,796 infertile men and 242,282 controls were followed for a mean of 3.6 and 3.1 years respectively. Overall, infertile men had a higher risk of death (Hazard Ratio [HR]= 1.42, 95% CI: 1.27-1.60) The diagnosis of azoospermia was associated with a significantly increased risk of death (HR= 2.01, 95% CI: 1.60-2.53) with a higher trend among men with oligospermia (HR: 1.17, 95% CI: 0.92-1.49) compared to controls. Subanalysis was done excluding prevalent cardiovascular and malignant disease (alone and combined) showing similar hazard ratios.

CONCLUSION

Male infertility is associated with a higher risk of mortality especially among azoospermic men. Prevalent disease (which is known to be higher among infertile men) did not explain the higher risk of death among infertile men. The implications for treatment and surveillance of infertile men require further study.