Semen quality and male reproductive health: the controversy about human sperm concentration decline

Objectives. To study the associations between kisspeptin levels in seminal plasma and blood plasma and semen quality. Materials and Methods. We conducted a male reproductive health survey in June 2014. A total of 666 volunteers were recruited from colleges in Chongqing, China. All volunteers completed a questionnaire including information on domestic characteristics and some potential confounders. We tested the kisspeptin levels in both blood and seminal plasma. Total seminal kisspeptin was calculated as the concentration of kisspeptin in seminal plasma multiplied by semen volume. Semen samples were tested according to the 2010 World Health Organization’s (WHO) guidelines. Spearman correlation and multivariate linear regression were used to explore the association between kisspeptin concentrations in seminal plasma and blood plasma and semen quality. Potential confounders that were adjusted for included age, abstinence time, body mass index (BMI), grade, and smoking. Results. The median of kisspeptin levels in seminal plasma was 60,000 times higher than kisspeptin in blood plasma (28.0 × 106 pg/ml versus 448.9 pg/ml). Each interquartile range (IQR) of kisspeptin in seminal plasma was associated with a 4.6% (95% confidence interval [CI]: 1.6%–7.6%) increase in sperm concentration. Each IQR of total kisspeptin was associated with a 7.7% (95% CI: 4.4%–11.0%) increase in total sperm number and a 7.8% (95% CI: 4.0%–11.7%) increase in total motile sperm count. Kisspeptin levels were further classified into quartiles and Q1 was set as the reference level. Subjects in the high total kisspeptin group had 57.5% (95% CI: 33.2%–86.2%) higher total sperm number than the reference group. Conclusion. The positive association between kisspeptin levels in seminal plasma and semen quality supported an important role for the KISS1/GPR54 system in male reproductive health. Kisspeptin may be a potential marker of male reproductive health and an alternative strategy for treating infertility.

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Effect of a phytoestrogen food supplement on reproductive health in normal males

Clinical Science ◽

10.1042/cs1000613 ◽

2001 ◽

Vol 100 (6) ◽

pp. 613-618 ◽

Cited By ~ 77

Author(s):

Julie H. MITCHELL ◽

Elizabeth CAWOOD ◽

David KINNIBURGH ◽

Anne PROVAN ◽

Andrew R. COLLINS ◽

...

Keyword(s):

Reproductive Health ◽

Reproductive Tract ◽

Semen Quality ◽

Sperm Quality ◽

Sperm Count ◽

Sperm Concentration ◽

Human Sperm ◽

Food Supplement ◽

Testicular Volume ◽

Semen Parameters

Animal studies and human intervention trials have demonstrated the cancer chemopreventive properties of plant phytoestrogens, and phytoestrogen supplements are now widely available ‘over-the-counter’. However, consumption of phytoestrogen-rich diets can cause impaired fertility and reproductive tract disorders in some animals and the apparent decline in human sperm quality over recent decades may be related to increased exposure to environmental endocrine disruptors. The present study determines the effects of a short-term phytoestrogen supplement on semen quality and serum sex steroid and gonadotrophin levels in human males. Healthy volunteers took a supplement containing 40 mg of isoflavones daily for 2 months and donated blood and semen samples monthly for 2 months before and 4 months after supplementation. Semen samples were analysed for ejaculate volume, sperm concentration, total sperm count, motility and morphology. Blood samples were analysed for sex hormone and gonadotrophin levels and phytoestrogen concentrations, and testicular volume was measured using an orchidometer. The phytoestrogen supplement increased plasma genistein and daidzein concentrations to approx. 1 µM and 0.5 µM respectively; yet, there was no observable effect on endocrine measurements, testicular volume or semen parameters over the study period. This is the first study to examine the effects of a phytoestrogen supplement on reproductive health in males. We conclude that the phytoestrogen dose consumed had no effect on semen quality.

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Secular variations in sperm quality: fact or science fiction?

Cadernos de Saúde Pública ◽

10.1590/s0102-311x2002000200004 ◽

2002 ◽

Vol 18 (2) ◽

pp. 403-412 ◽

Cited By ~ 14

Author(s):

Luc Multigner ◽

Alejandro Oliva

Keyword(s):

Science Fiction ◽

Semen Quality ◽

Sperm Quality ◽

Meta Analysis ◽

Sperm Concentration ◽

Human Sperm ◽

Public Health Issue ◽

Human Populations ◽

Homogeneous Groups ◽

Secular Variations

The debate concerning the possible degradation in human sperm quality began in the 1970s, was revived at the beginning of the 1990s and has continued to mobilize the scientific community ever since. After the meta-analysis by Carlsen et al. (1992) showing a decline in human semen quality over the last 50 years, several groups investigated the sperm characteristics of more or less homogeneous groups of men who had provided semen at the same center for 10 to 20 years. A significant decrease in sperm concentration was reported in some studies, but not in others. Meanwhile, there is an increasing number of reports suggesting that physical and chemical factors introduced and spread by human activity in the environment may have contributed to sperm decline. At the end of the 20th century the debate on declining semen quality is not closed. The lack of certainty and the serious consequences that such a decline would have on the fertility of human populations make this an important public health issue at the start of the 21st century. For this reason, intensive research should be developed in both fundamental and epidemiological domains, particularly in South America, where industrial and agricultural pollution pose a serious threat to the population.

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Regional differences and temporal trends in male reproductive health disorders: Semen quality may be a sensitive marker of environmental exposures

Molecular and Cellular Endocrinology ◽

10.1016/j.mce.2011.05.048 ◽

2012 ◽

Vol 355 (2) ◽

pp. 221-230 ◽

Cited By ~ 84

Author(s):

Loa Nordkap ◽

Ulla Nordström Joensen ◽

Martin Blomberg Jensen ◽

Niels Jørgensen

Keyword(s):

Reproductive Health ◽

Regional Differences ◽

Semen Quality ◽

Temporal Trends ◽

Environmental Exposures ◽

Health Disorders ◽

Male Reproductive Health ◽

Sensitive Marker

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Efeito da atividade física sobre a qualidade seminal

Caderno de Educação Física e Esporte ◽

10.36453/2318-5104.2020.v18.n1.p41 ◽

2020 ◽

Vol 18 (1) ◽

pp. 41-47

Author(s):

Leonardo Monteiro Nesello ◽

Fábio Pasqualotto

Keyword(s):

Physical Activity ◽

Reproductive Health ◽

Clinical Evidence ◽

Semen Quality ◽

Moderate Physical Activity ◽

Hormonal Changes ◽

Physical Activity Intensity ◽

Activity Intensity ◽

Male Reproductive Health ◽

Intense Physical Activity

INTRODUÇÃO: A saúde reprodutora masculina pode ser influenciada devida à prática de atividade física, e com isso tem-se aumentado o número de estudos que analisam o efeito da atividade física na qualidade seminal. Descobertas apontam que mudanças significativas na qualidade do sêmen podem ocorrer com a prática de atividade física, que pode alterar sua qualidade de acordo com o tipo de atividade física, a intensidade e a duração. OBJETIVO: Neste contexto, o presente estudo realizou uma análise detalhada da literatura atual com o objetivo de verificar o efeito de diferentes atividades físicas sobre a saúde reprodutora masculina. MÉTODO: Trata-se de uma revisão sistemática feita nas bases de dados do PubMed. Utilizou-se os itens propostos pelo PRISMA para a busca, seleção e extração de dados. De acordo com o fluxograma proposto, 244 artigos foram identificados e, destes, 12 foram selecionados. RESULTADOS: Apoiada por fortes evidências clínicas, esta revisão sugere que a atividade física intensa pode provocar fortes alterações hormonais e prejudicar a qualidade seminal. Já a atividade física moderada parece ter um efeito neutro ou benéfico para a qualidade do sêmen. Além disso, o efeito da atividade física na qualidade do sêmen pode ser diferente de acordo com o tipo de atividade física. CONCLUSÃO: Frente às evidências, ainda existe falta de conclusões sólidas sobre esse assunto, devido ao fato de existir muita contradição entre os estudos existentes e da atividade física não ser facilmente quantificada. ABSTRACT. Effect of physical activity on seminal quality, BACKGROUND: Male reproductive health may be influenced by physical activity, and this has increased the number of studies that analyze the effect of physical activity on seminal quality. Findings indicate that significant changes in semen quality can occur due to the practice of physical activity, which can alter its quality according to the type of physical activity, intensity and duration. OBJECTIVE: In this context, the present study performed a detailed analysis of the current literature with the objective of verifying the effect of different physical activity on male reproductive health. METHODS: A systematic review performed on the PubMed databases. The items proposed by PRISMA were used for searching, selecting and extracting data. According to the proposed flowchart, 244 articles were indentified and, of these, 12 were selected. RESULTS: Supported by strong clinical evidence, this review shows that intense physical activity can cause strong hormonal changes and impair seminal quality. On the other hand, moderate physical activity seems to have a neutral or beneficial effect on semen quality. In addition, the effect of physical activity on semen quality may differ according to the type of physical activity. CONCLUSION: Faced with the evidence, there is still a lack of solid conclusions on this subject, due to the fact that there is a lot of contradiction between the existing studies and that physical activity can not be easily quantified.

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Estrogens and falling sperm counts

Reproduction Fertility and Development ◽

10.1071/rd00103 ◽

2001 ◽

Vol 13 (4) ◽

pp. 317 ◽

Cited By ~ 44

Author(s):

D. J. Handelsman

Keyword(s):

Reproductive Health ◽

Male Fertility ◽

Human Sperm ◽

Population Based ◽

Human Testis ◽

Estrogen Exposure ◽

Surrogate Variables ◽

Sperm Counts ◽

Sperm Output ◽

Male Reproductive Health

Extravagant claims have been made repeatedly in recent years that human sperm counts are falling and that global exposure to environmental estrogens are responsible. The basis for these two distinct claims is reviewed. The claims of falling human sperm output, reviving an old debate, are prompted by a paper by Carlsen et al. (1992). This meta-analysis, however, is marred by numerous flaws that invalidate its claims. Major defects include severe heterogeneity of component studies, rendering them unsuitable for aggregation, and defective data analysis based on arithmetic mean rather than median, which showed no significant changes over time. This debate is likely to remain unresolved until valid, representative population-based studies of human sperm output can be achieved. None have been reported, or seem feasible in the near future, and so alternative strategies, based on surrogate variables for human male fertility not requiring sperm counts, need to be developed and validated. The plausible hypothesis that prenatal estrogen exposure might influence development of the human testis through effects on Sertoli cell replication and sperm carrying capacity has, however, been conclusively refuted by studies of boys born to women exposed to high doses of oral diethylstilbestrol during pregnancy. Neither fertility nor sperm output were adversely influenced by massive maternal estrogen exposure during pregnancy, although minor urogenital malformations did occur. The still wider claims of deteriorating male reproductive health, notably changes in prevalence or incidence of hypospadias or cryptorchidism, also lack convincing population-based evidence, although cancer registry data indicate a gradual increase in testis cancer in some countries. In summary, the available evidence does not support claims of falling sperm counts or any general deterioration in male reproductive health. Population-based studies of valid surrogate variables for male fertility not requiring semen analysis are needed. If population-based evidence regarding male fertility or sperm output could be generated, it is highly unlikely that prenatal estrogen exposure could be a valid explanation of any deterioration as massive maternal exposure to oral estrogen has negligible effects on male fertility or sperm output.

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Environmental anti-androgens and male reproductive health: focus on phthalates and testicular dysgenesis syndrome

Reproduction ◽

10.1530/rep.1.00025 ◽

2004 ◽

Vol 127 (3) ◽

pp. 305-315 ◽

Cited By ~ 276

Author(s):

Jane S Fisher

Keyword(s):

Reproductive Health ◽

Reproductive Tract ◽

Semen Quality ◽

Phthalate Esters ◽

Male Reproductive Tract ◽

Testicular Dysgenesis Syndrome ◽

Geographical Variations ◽

Human Male ◽

Testicular Dysgenesis ◽

Male Reproductive Health

The amount of research into endocrine disruption has exploded over the past decade and a re-evaluation of the state of research in this area is timely. There are debates about whether human male reproductive health is really declining and whether endocrine disrupting chemicals play any role in the perceived decline. Most data currently conclude that there are wide geographical variations in semen quality and in the incidence of testicular cancer, cryptorchidism and hypospadias. This review aims to give a brief overview of the issues surrounding the perceived decline in human male reproductive health and the importance of the hormonal environment for the development of the testis and reproductive tract. The consequences for the male reproductive tract of abnormal androgen levels or action are discussed with reference to environmental anti-androgenic compounds. The in vivo data on several anti-androgenic compounds that have been administered to pregnant rodents during the period of male reproductive tract development are assessed with attention to the effects on the male offspring. Finally, the data on in utero phthalate administration are discussed in detail to illustrate the similarities between the effects of some phthalate esters and the human male reproductive tract disorders which comprise testicular dysgenesis syndrome (TDS).

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Association between ambient particulate matter exposure and semen quality in fertile men

Environmental Health ◽

10.1186/s12940-022-00831-5 ◽

2022 ◽

Vol 21 (1) ◽

Author(s):

Wei Wu ◽

Yiqiu Chen ◽

Yuting Cheng ◽

Qiuqin Tang ◽

Feng Pan ◽

...

Keyword(s):

Particulate Matter ◽

Sperm Motility ◽

Semen Quality ◽

Large Population ◽

Sperm Concentration ◽

Head Displacement ◽

Straight Line ◽

Distance Weighting ◽

Sperm Development ◽

Male Reproductive Health

Abstract Background Several studies have suggested adverse effects of particulate matter (PM) exposure on male reproductive health; few have investigated the association between PM exposure and semen quality in a large population of fertile men. Methods We evaluated 14 parameters of semen quality in 1554 fertile men in Nanjing from 2014 to 2016. Individual exposure to particular matter ≤10 μm in diameter (PM10) and ≤ 2.5 μm in diameter (PM2.5) during key periods of sperm development (0-90, 0-9, 10-14, 15-69, and 70-90 days before semen collection) were estimated by inverse distance weighting interpolation. Associations between PM exposure and semen quality were estimated using multivariable linear regression. Results Higher 90-days average PM2.5 was in association with decreased sperm motility (2.21% for total motility, 1.93% for progressive motility per 10 μg/m3 increase, P < 0.001) and four quantitative aspects of sperm motion (curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), and amplitude of lateral head displacement (ALH), P < 0.01). The association between PM2.5 exposure and semen quality were generally stronger for the earlier exposure window (70-90 days prior to ejaculation) than for recent exposure (0-9, 10-14, or 15-69 days). In the subgroup of men who had normal sperm parameters (n = 1019), similar results were obtained. Ninety-days PM10 exposure was associated only with decreased VCL and VAP and was not related to sperm concentration. Conclusions Exposure to PM2.5 adversely affects semen quality, specifically lower sperm motility, in fertile men. Graphical abstract

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In utero exposure to persistent organochlorine pollutants and reproductive health in the human male

Reproduction ◽

10.1530/rep-13-0488 ◽

2014 ◽

Vol 148 (6) ◽

pp. 635-646 ◽

Cited By ~ 17

Author(s):

Anne Vested ◽

Cecilia H Ramlau-Hansen ◽

Sjurdur F Olsen ◽

Jens Peter Bonde ◽

Henrik Støvring ◽

...

Keyword(s):

Reproductive Health ◽

Semen Quality ◽

Sperm Concentration ◽

In Utero ◽

Reproductive Hormone ◽

Blood Samples ◽

Persistent Organochlorine ◽

Hormone Levels ◽

Organochlorine Pollutants ◽

Exposure Levels

Persistent organochlorine pollutants (POPs) are ubiquitous, bioaccumulative compounds with potential endocrine-disrupting effects. They cross the placental barrier thereby resulting inin uteroexposure of the developing fetus. The objective of this study was to investigate whether maternal serum concentrations of polychlorinated biphenyls (PCBs) andp,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) during pregnancy are associated with son's semen quality and reproductive hormone levels. During 2008–2009, we recruited 176 male offspring from a Danish cohort of pregnant women who participated in a study in 1988–1989. Each provided semen and blood samples that were analyzed for sperm concentration, total sperm count, motility, and morphology, and reproductive hormone levels, respectively. The maternal blood samples were collected in pregnancy week 30 and were analyzed for the concentrations of six PCBs (PCB-118, -138, -153, -156, -170, and -180) andp,p′-DDE. The potential associations betweenin uteroexposure to ΣPCBs (pmol/ml), Σdioxin like-(DL) PCBs (PCB-118 and -156) (pmol/ml), andp,p′-DDE and semen quality and reproductive hormone levels were investigated using multiple regression. Maternal median (range) exposure levels of ΣPCB, ΣDL-PCB, andp,p′-DDE were 10.0 (2.1–35.0) pmol/ml, 0.8 (0.2–2.7) pmol/ml, and 8.0 (0.7–55.3) pmol/ml, respectively, reflecting typical background exposure levels in the late 1980s in Denmark. Results suggested thatin uteroexposure to ΣPCB, ΣDL-PCB, andp,p′-DDE was not statistically significantly associated with semen quality measures or reproductive hormone levels. Thus, results based on maternal PCB andp,p′-DDE concentrations alone are not indicative of long-term consequences for male reproductive health; however, we cannot exclude that these POPs in concert with other endocrine-modulating compounds may have adverse effects.

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