Habitual alcohol consumption associated with reduced semen quality and changes in reproductive hormones; a cross-sectional study among 1221 young Danish men

Exposure to Per- and Polyfluoroalkyl Substances and Timing of Puberty in Norwegian Boys: Data from the Bergen Growth Study 2

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants with endocrine-disruptive properties. Their impact on puberty in boys is unclear. In this cross-sectional study, we investigated the association between PFAS exposure and pubertal timing in 300 Norwegian boys (9-16 years), enrolled in the Bergen Growth Study 2 during 2016. We measured 19 PFAS in serum samples and used objective pubertal markers, including ultrasound-measured testicular volume (USTV), Tanner staging of pubic hair development, and serum levels of testosterone, luteinizing hormone, and follicle-stimulating hormone. In addition to logistic regression of single pollutants and the sum of PFAS, Bayesian and elastic net regression were used to estimate the contribution of the individual PFAS. Higher levels of the sum of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid (PFHxS) were associated with later pubertal onset according to USTV (age-adjusted odds ratio (AOR): 2.20, 95% confidence interval (CI): 1.29, 3.93) and testosterone level (AOR: 2.35, 95% CI: 1.34, 4.36). Bayesian modeling showed that higher levels of PFNA and PFHxS were associated with later pubertal onset by USTV, while higher levels of PFNA and perfluoroundecanoic acid (PFUnDA) were associated with later pubertal onset by testosterone level. Our findings indicate that certain PFAS were associated with delay in male pubertal onset.

Behind the Genetics: The Role of Epigenetics in Infertility-Related Testicular Dysfunction

In recent decades, we have witnessed a progressive decline in male fertility. This is partly related to the increased prevalence of chronic diseases (e.g., obesity and diabetes mellitus) and risky lifestyle behaviors. These conditions alter male fertility through various non-genetic mechanisms. However, there is increasing evidence that they are also capable of causing sperm epigenetic alterations, which, in turn, can cause infertility. Furthermore, these modifications could be transmitted to offspring, altering their general and reproductive health. Therefore, these epigenetic modifications could represent one of the causes of the progressive decline in sperm count recorded in recent decades. This review focuses on highlighting epigenetic modifications at the sperm level induced by non-genetic causes of infertility. In detail, the effects on DNA methylation, histone modifications, and the expression profiles of non-coding RNAs are evaluated. Finally, a focus on the risk of transgenerational inheritance is presented. Our narrative review aims to demonstrate how certain conditions can alter gene expression, potentially leading to the transmission of anomalies to future generations. It emphasizes the importance of the early detection and treatment of reversible conditions (such as obesity and varicocele) and the modification of risky lifestyle behaviors. Addressing these issues is crucial for individual health, in preserving fertility, and in ensuring the well-being of future generations.

Associations between dietary macronutrient quality and asthenozoospermia risk: a hospital-based case-control study

Background & aims: Macronutrients are the main part of the human diet and can affect multiple health outcomes. Nevertheless, associations between dietary macronutrient quality and asthenozoospermia risk have not been reported to date. Thus, this study aimed to be the first to explore the associations between macronutrient quality and asthenozoospermia risk using the novel multidimensional macronutrient quality index (MQI). Methods: A case-control study was conducted at infertility clinics of Shengjing Hospital of China Medical University during June and December 2020, including 552 asthenozoospermia cases and 585 normozoospermia controls. Data on diet were collected using a validated food frequency questionnaire. MQI was estimated according to the carbohydrate quality index (CQI), fat quality index (FQI), and protein quality index (PQI). Binary logistic regression models were performed to calculate the odds ratio (OR) with a 95% confidence interval (CI). Subgroup and interaction analyses were performed based on age, body mass index, physical activity, smoking, drinking, and education level. Dose-response relationships were evaluated by restricted cubic splines. Sensitivity analyses were performed in two ways. First, participants with a dietary change were excluded to lower potential reverse causation. Then, we used the healthy plate protein source quality index instead of PQI to redefine MQI. Results: No statistically significant association was observed between dietary MQI and asthenozoospermia risk (OR = 1.24, 95% CI: 0.88-1.73). The sub-indices of MQI, CQI, FQI, and PQI, failed to be identified as having a statistically significant association with asthenozoospermia risk (OR = 1.35, 95% CI: 0.92-1.97 for CQI; OR = 1.13, 95% CI: 0.84-1.53 for FQI; OR = 1.28, 95% CI: 0.92-1.78 for PQI). However, CQI showed a positive association with the risk of asthenozoospermia among non-drinkers (Ptrend < 0.05) and highly educated participants (OR = 1.82, 95% CI: 1.13-2.94; Ptrend < 0.05). Additionally, there was a multiplicative interaction between CQI and education level for asthenozoospermia risk (P < 0.05). Conclusions: Our findings demonstrated no association of MQI and its sub-indices with asthenozoospermia risk except for CQI. Although our findings are mostly non-significant, they contribute novel knowledge to this research field and lay the foundation for future studies.

The chronic alcohol consumption influences the gonadal axis in men: Results from a meta-analysis

BACKGROUND

Low testosterone concentrations affect 2-13% of adult males, with a direct association between reduction in testosterone (T) concentrations and cardiovascular events. Lifestyle habits have been linked to visceral fat accumulation and endocrine disorders like secondary hypogonadism. Alcohol intake has also been a topic of debate, with studies showing a detrimental effect on sperm production and underlying mechanisms. This meta-analysis aims to comprehensively evaluate the effect of alcohol consumption on T serum concentrations in adult men.

METHODS

The literature search included only controlled clinical trials comparing men who drink alcohol to men who do not, or who assumed placebo or nonalcoholic beverages. The primary outcome was the comparison of total testosterone serum concentrations between the study and control groups. The publications were examined for publication bias using Egger's test.

RESULTS

Twenty-one studies were included in the analysis for a total of 30 trials that examined the effects of alcohol consumption on testosterone level in 10,199 subjects. The meta-analysis showed that alcohol consumption overall is related to significant reduction in circulating concentrations of total testosterone (mean difference [MD] = -4.02; 95% CI -6.30, -1.73), free T (MD = -0.17; 95% CI -0.23, -0.12), sex hormone binding globulin (SHBG) (MD = -1.94; 95% CI -3.37, -0.48), an increase in estradiol (E2) (MD = 7.65; 95% CI 1.06, 14.23) and neutral effect on luteinizing hormone (LH) (MD = -0.15; 95% CI -0.36, 0.06), independently by age, body mass index (BMI), E2, and LH serum concentrations and alcohol intake. However, these results are evident only in healthy men exposed to chronic alcohol consumption and not in those with a recognized diagnosis of alcohol use disorder or after acute alcohol intake.

CONCLUSION

This study suggests how chronic alcohol consumption may inhibit the gonadal axis in healthy men, although the exact pathophysiological mechanisms connecting alcohol exposure and steroidogenesis are still not completely clarified.

The role of neurosteroids in posttraumatic stress disorder and alcohol use disorder: A review of 10 years of clinical literature and treatment implications

Rates of alcohol use disorder (AUD) are increasing in men and women and there are high rates of concurrent posttraumatic stress disorder (PTSD) and AUD. AUD and PTSD synergistically increase symptomatology and negatively affect treatment outcomes; however, there are very limited pharmacological treatments for PTSD/AUD. Neurosteroids have been implicated in the underlying neurobiological mechanisms of both PTSD and AUD and may be a target for treatment development. This review details the past ten years of research on pregnenolone, progesterone, allopregnanolone, pregnanolone, estradiol, testosterone and dehydroepiandrosterone/dehydroepiandrosterone-sulfate (DHEA/DHEA-S) in the context of PTSD and AUD, including examination of trauma/alcohol-related variables, such as stress-reactivity. Emerging evidence that exogenous pregnenolone, progesterone, and allopregnanolone may be promising, novel interventions is also discussed. Specific emphasis is placed on examining the application of sex as a biological variable in this body of literature, given that women are more susceptible to both PTSD diagnoses and stress-related alcohol consumption.

Inter- and transgenerational heritability of preconception chronic stress or alcohol exposure: Translational outcomes in brain and behavior

Chronic stress and alcohol (ethanol) use are highly interrelated and can change an individual's behavior through molecular adaptations that do not change the DNA sequence, but instead change gene expression. A recent wealth of research has found that these nongenomic changes can be transmitted across generations, which could partially account for the "missing heritability" observed in genome-wide association studies of alcohol use disorder and other stress-related neuropsychiatric disorders. In this review, we summarize the molecular and behavioral outcomes of nongenomic inheritance of chronic stress and ethanol exposure and the germline mechanisms that could give rise to this heritability. In doing so, we outline the need for further research to: (1) Investigate individual germline mechanisms of paternal, maternal, and biparental nongenomic chronic stress- and ethanol-related inheritance; (2) Synthesize and dissect cross-generational chronic stress and ethanol exposure; (3) Determine cross-generational molecular outcomes of preconception ethanol exposure that contribute to alcohol-related disease risk, using cancer as an example. A detailed understanding of the cross-generational nongenomic effects of stress and/or ethanol will yield novel insight into the impact of ancestral perturbations on disease risk across generations and uncover actionable targets to improve human health.

Genetic correlations of alcohol consumption and alcohol use disorder with sex hormone levels in females and males

Background

Alcohol consumption behaviors and alcohol use disorder risk and presentation differ by sex, and these complex traits are associated with blood concentrations of the steroid sex hormones, testosterone and estradiol, and their regulatory binding proteins, sex hormone binding globulin (SHBG) and albumin. Genetic variation is associated with alcohol consumption and alcohol use disorder, as well as levels of steroid sex hormones and their binding proteins.

Methods

To assess the contribution of genetic factors to previously described phenotypic associations between alcohol-use traits and sex-hormone levels, we estimated genetic correlations (rg) using summary statistics from prior published, large sample size genome-wide association studies (GWAS) of alcohol consumption, alcohol dependence, testosterone, estradiol, SHBG, and albumin.

Results

For alcohol consumption, we observed positive genetic correlation (i.e. genetic effects in the same direction) with total testosterone in males (rg = 0.084, p = 0.007) and trends toward positive genetic correlation with bioavailable testosterone (rg = 0.060, p = 0.084) and SHBG in males (rg = 0.056, p = 0.086) and with albumin in a sex-combined cohort (rg = 0.082, p = 0.015); however in females, we observed positive genetic correlation with SHBG (rg = 0.089, p = 0.004) and a trend toward negative genetic correlation (i.e. genetic effects in opposite directions) with bioavailable testosterone (rg = -0.064, p = 0.032). For alcohol dependence, we observed a trend toward negative genetic correlation with total testosterone in females (rg = -0.106, p = 0.024) and positive genetic correlation with BMI-adjusted SHBG in males (rg = 0.119, p = 0.017). Several of these genetic correlations differed between females and males and were not in the same direction as the corresponding phenotypic associations.

Conclusions

Findings suggest that shared genetic effects may contribute to positive associations of alcohol consumption with albumin in both sexes, as well as positive associations between alcohol consumption and bioavailable testosterone and between alcohol dependence and SHBG in males. However, relative contributions of heritable and environmental factors to associations between alcohol-use traits and sex-hormone levels may differ by sex, with genetic factors contributing more in males and environmental factors contributing more in females.

Temporal Trends in Semen Quality, Hormone Levels, and Substance Use Among Infertile Men in Pre- and Post-Cannabis Legalization Eras in Canada

Background: The Cannabis Act (Bill C-45) was enacted in 2018, to legalize and regulate the use, production, and sale of nonmedical cannabis in Canada. While public health and safety implications of cannabis legalization have yet to be elucidated, the wide availability of cannabis necessitates health care providers to be knowledgeable about therapeutic potential and side effects of use. This study aimed to examine the temporal trends over two decades and the impact of the Cannabis Act in Canada, implemented in October 2018, on substance use, semen parameters, and testosterone levels of infertile men. Methods: We conducted a retrospective cohort study from a prospectively maintained database of a single infertility clinic. Demographic, fertility, and substance use history were correlated with semen and hormone assessments. Temporal trends in cannabis use and semen quality between 2001 and 2021 were investigated and compared between pre-cannabis legalization eras (PRCL) and post-cannabis legalization eras (POCL). Results: Our cohort included 11,630 patients (9411 PRCL and 2230 POCL). Cannabis use increased by 8.4% per year (p<0.001), while alcohol and tobacco consumption declined (0.8% and 1.5% per year, p<0.05 and p=0.004, respectively). Similar trends were noticed in the POCL, with higher rates of cannabis use (22.4% vs. 12.9%, p<0.001) and decreased tobacco and alcohol intake (15.2% vs. 17.7%, p=0.005 and 50.5% vs. 55.2%, p<0.001, respectively) compared to the PRCL group. Semen concentration was lower in the POCL group (24.8±44.8 vs. 28.7±48.3 million/mL, p=0.03). Testosterone did not differ between the cohorts. Comparison between cannabis users (n=1715) and nonusers (n=9924) demonstrated a slight increase in sperm motility (25.9%±15.3% vs. 23.9%±15.0%, p=0.002) and decreased sperm concentration among users (27.6±53.5 vs. 23.9±15.0 million/mL, p=0.03). Conclusion: A nearly 10% rise in cannabis use in the POCL era was observed among men being investigated for infertility. Our data suggest cannabis use may be associated with an increase in testosterone, slightly improved sperm motility, and decreased sperm concentration.

Association between self-reported mobile phone use and the semen quality of young men

OBJECTIVES

To investigate the association between mobile phone exposure and semen parameters.

DESIGN

A nationwide cross-sectional study.

SETTING

Andrology laboratories in close proximity to 6 army recruitment centers.

PATIENTS

In total, 2886 men from the general Swiss population, 18-22 years old, were recruited between 2005 and 2018 during military conscription.

INTERVENTION

Participants delivered a semen sample and completed a questionnaire on health and lifestyle, including the number of hours they spent using their mobile phones and where they placed them when not in use.

MAIN OUTCOME MEASURES

Using logistic and multiple linear regression models, adjusted odds ratios and β coefficients were determined, respectively. The association between mobile phone exposure and semen parameters such as volume, sperm concentration, total sperm count (TSC), motility, and morphology was then evaluated.

RESULTS

A total of 2759 men answered the question concerning their mobile phone use, and 2764 gave details on the position of their mobile phone when not in use. In the adjusted linear model, a higher frequency of mobile phone use (>20 times per day) was associated with a lower sperm concentration (adjusted β: -0.152; 95% confidence interval: -0.316; 0.011) and a lower TSC (adjusted β: -0.271; 95% confidence interval: -0.515; -0.027). In the adjusted logistic regression model, this translates to a 30% and 21% increased risk for sperm concentration and TSC to be below the World Health Organization reference values for fertile men, respectively. This inverse association was found to be more pronounced in the first study period (2005-2007) and gradually decreased with time (2008-2011 and 2012-2018). No consistent associations were observed between mobile phone use and sperm motility or sperm morphology. Keeping a mobile phone in the pants pocket was not found to be associated with lower semen parameters.

CONCLUSION

This large population-based study suggests that higher mobile phone use is associated with lower sperm concentration and TSC. The observed time trend of decreasing association is in line with the transition to new technologies and the corresponding decrease in mobile phone output power. Prospective studies with improved exposure assessment are needed to confirm whether the observed associations are causal.

[Male infertility, environment and lifestyle]

BACKGROUND

Since the 1970s, there has been a quantitative and qualitative decline in sperm parameters. The main hypothesis to explain such a rapid evolution is the involvement of environmental and behavioral phenomena.

METHODS

A bibliographic search limited to English and French literature in men published before 7/2023 was carried out on the links between fertility and pollution, xenobiotics, tobacco, narcotics, cannabis, alcohol, weight, sport, sedentary lifestyle, sleep and anabolics.

RESULTS

Profound changes in lifestyle have occurred over the past 50 years: reduced sleep time, sedentary lifestyle, dietary changes, tobacco consumption, use of narcotics and anabolics. These changes have a proven impact on spermogram parameters, and should be corrected in an effort to optimize reproductive health. Other environmental parameters: pollution, exposure to heavy metals, exposure to xenobiotics, phthalates and pesticides… will be more difficult to exclude from patients' daily lives, but deserve to be taken more into account.

CONCLUSION

This review should help the urologist to assess and counsel patients in order to improve their reproductive health. These factors should be routinely investigated in infertile men.

Male infertility

Clinical infertility is the inability of a couple to conceive after 12 months of trying. Male factors are estimated to contribute to 30-50% of cases of infertility. Infertility or reduced fertility can result from testicular dysfunction, endocrinopathies, lifestyle factors (such as tobacco and obesity), congenital anatomical factors, gonadotoxic exposures and ageing, among others. The evaluation of male infertility includes detailed history taking, focused physical examination and selective laboratory testing, including semen analysis. Treatments include lifestyle optimization, empirical or targeted medical therapy as well as surgical therapies that lead to measurable improvement in fertility. Although male infertility is recognized as a disease with effects on quality of life for both members of the infertile couple, fewer data exist on specific quantification and impact compared with other health-related conditions.

Parental substance use disorder and risk of intellectual disability in offspring in Sweden: a national register study

Background

Intellectual disability (ID) is a disorder with unknown aetiology in many cases. Maternal alcohol use is a known risk factor for ID, but less is known about the importance of maternal and paternal substance use disorder (SUD) and risk of ID in offspring.

Methods

Data from multiple nationwide registers were used to create a cohort of children born from January 01, 1978 to December 31, 2002. All participants were born in Sweden, had available parental identification information and did not emigrate or die before age 12 (n = 1,940,820). Logistic regression modelling was performed with exposure defined as having a parent who received any SUD diagnosis, including alcohol use disorder (AUD) and drug use disorder (DUD). The outcome was registration of diagnosis of any form of ID. First, we analysed the risk of ID if parental SUD was registered prior to childbirth with stepwise adjustment of multiple covariates. Second, the effect of timing of SUD diagnosis in relation to childbirth was analysed.

Findings

Of 37,410 offspring with parental SUD registered prior to birth, 3.0% (n = 1110) had any form of ID compared to 1.2% (n = 23,168) of those 1,903,410 individuals without parental SUD prior birth. Parental SUD prior birth was associated with an increased risk of any form of ID (Odds Ratio [OR]: 2.3 [2.2-2.5]), with ORs similar for maternal (OR: 2.3 [2.1-2.5]) and paternal SUD (OR: 2.3 [2.1-2.5]). These ORs were reduced but remained statistically significant after adjusting for parental education, migration, psychiatric comorbidity, and co-parent SUD (OR parental SUD: 1.6 [1.5-1.8]; OR maternal SUD: 1.4 [1.2-1.5]; OR paternal SUD: 1.6 [1.5-1.7]). Parental SUD was associated with increased risk of ID in offspring irrespective of timing of diagnosis, but if mothers or fathers were diagnosed with AUD during pregnancy (OR maternal AUD: 5.0 [3.1-8.2]; OR paternal AUD: 2.8 [2.2-3.6]), the risk was significantly greater than if the AUD diagnosis was first registered after childbirth (OR maternal AUD: 1.9 [1.8-2.0]; OR paternal AUD: 1.6 [1.6-1.7]).

Interpretation

Both paternal and maternal SUD were associated with an increased risk of ID in offspring, with greatest risk observed when AUD was diagnosed during pregnancy. Possible mechanisms may involve shared genetic and environmental factors, including toxic effects from alcohol intake. These findings have clinical implications in suggesting that parental SUD in either parent represents a possibly modifiable risk factor to consider when developing prevention, diagnostics and treatment programs for children with ID.

Funding

Stockholm County Council, the Research Council of the Swedish Alcohol Retailing Monopoly, Fredrik and Ingrid Thurings stiftelse, Academy of Finland, the Swedish Research Council and the Swedish Research Council for Health, Working Life and Welfare, Nordforsk by the Nordic Council of Ministers and the Polish Medical Research Agency.

Investigating the association between alcohol intake and male reproductive function: A current meta-analysis

Background

Alcohol use and alcohol-related health problems are on the rise in developing countries. This meta-analysis was conducted to determine the effects of alcohol consumption on human male reproductive function through semen parameters, antioxidants in semen, sperm DNA fragmentation, and sex hormones.

Methods

Studies regarding the effects of alcohol consumption on male reproductive function were searched on databases. Based on the random-effects model, STATA software was used to analyze and synthesize the selected studies. Alcoholics, moderate alcoholics, heavy alcoholics, and no alcoholics values were compared using the standard mean difference. Publications were assessed for publication bias by the Egger test.

Result

Forty studies were selected from databases examining the effect of alcohol consumption on male reproductive health in 23,258 people on five continents of the world. The meta-analysis revealed that alcohol intake reduced semen volume during each ejaculation (SMD = -0.51; 95% CI -0.77, -0.25). However, there were no significant associations with other semen indicators such as density, mobility, and normal and abnormal sperm count from this analysis. In addition, drinking alcohol lowered antioxidant enzymes in semen (SMD = -7.93; 95% CI -12.59, -3.28) but had no effect on sperm DNA fragmentation. Finally, the results showed a decrease in general testosterone levels (SMD = -1.60; 95% CI -2.05, -1.15), Follicle Stimulating Hormone (SMD = -0.47; 95% CI -0.88, -0.05), Luteinizing Hormone (SMD = -1.35; 95% CI -1.86, -0.83), but no effect in other sex hormones named as estradiol, Inhibin B and Sex Hormone-Binding Globulin. Furthermore, when analyzing subgroups at different drinking levels, the results showed that the moderate alcoholic group (less than 7 units/week) had no change in the semen index. Meanwhile, the group of heavy alcoholics (more than 7 units/week) harmed the semen index and sex hormones, especially by increasing estradiol.

Conclusion

There is evidence that alcohol consumption affected semen volume and antioxidant, reproductive hormones thus negatively affecting male reproductive function. This study might be necessary to make recommendations regarding alcohol consumption for men.

Male Clinical Parameters (Age, Stature, Weight, Body Mass Index, Smoking History, Alcohol Consumption) Bear Minimal Relationship to the Level of Sperm DNA Fragmentation

This retrospective cohort study reports on 1291 males who were the partners of women presenting with infertility requiring assisted reproduction and who had sperm DNA fragmentation (SDF) levels measured by the Halosperm test. These men provided clinical and biometric details which included their age, stature, weight, and body mass index (BMI). Of these men, 562 (43.5%) provided detailed historical records of their smoking and alcohol histories. The aim of this study was to determine whether any clinical and biometric parameters, or main lifestyle factors, had any influence on SDF. We found that the only clinical parameter with a direct correlation was that of advancing age (r = 0.064, p = 0.02), but none of the biometric parameters of stature, weight, or BMI showed any significant correlation. In respect to lifestyle, there were significant correlations with smoking history, but not in the way we expected. Our data showed significantly elevated SDF levels among non-smokers (p = 0.03) compared with smokers. We also found that, among the non-smokers, ex-smokers had higher SDF levels (p = 0.03). With respect to alcohol, consumers did not show any significant differences in SDF levels. These lifestyle findings did not show any significant relevance with respect to an SDF level of <15% or ≥15%. Furthermore, logistic regression analysis excluded age as a confounder in these lifestyle findings. It is therefore concluded that, apart from age, both clinical and lifestyle aspects have minimal relevance to SDF.

Unlocking the mystery associated with infertility and prostate cancer: an update

Male-specific reproductive disorders and cancers have increased intensely in recent years, making them a significant public health problem. Prostate cancer (PC) is the most often diagnosed cancer in men and is one of the leading causes of cancer-related mortality. Both genetic and epigenetic modifications contribute to the development and progression of PC, even though the exact underlying processes causing this disease have yet to be identified. Male infertility is also a complex and poorly understood phenomenon believed to afflict a significant portion of the male population. Chromosomal abnormalities, compromised DNA repair systems, and Y chromosome alterations are just a few of the proposed explanations. It is becoming widely accepted that infertility shares a link with PC. Much of the link between infertility and PC is probably attributable to common genetic defects. This article provides an overview of PC and spermatogenic abnormalities. This study also investigates the link between male infertility and PC and uncovers the underlying reasons, risk factors, and biological mechanisms contributing to this association.

Associations of sex-related steroid hormones and proteins with alcohol dependence: A United Kingdom Biobank study

BACKGROUND

Sex-related steroid hormones and proteins may contribute to the sex differences in the characteristics and health consequences of alcohol use disorder. This study aimed to examine the associations between alcohol dependence (AD) and sex-related hormones/proteins using a population-based dataset.

METHODS

We retrieved serum total testosterone (TT) and estradiol (TE2), sex hormone binding globulin (SHBG), and albumin levels along with clinical data from the UK Biobank. Hormone/protein levels were compared between AD (lifetime AD and/or related diagnoses; 2218 males; 682 females) and control (no aforementioned diagnoses and AUDIT<8; 198,058 males; 250,830 females) groups with sex-dependent linear regression models adjusting for age and body mass index. Moderation and mediation analyses were performed to test whether SHBG was a moderator and/or mediator between hormones and AD or current drinking.

RESULTS

AD males had higher TT, TE2, and SHBG levels but lower bioavailable testosterone, bioavailable estradiol, and albumin levels than controls (padjusted<0.001). After adjusting for menopause, AD females had higher TT and lower albumin levels than controls (padjusted<0.001). These differences remained after accounting for current drinking frequency (p < 0.001). SHBG moderated TT's effect on AD in males (pinteraction<0.001). SHBG was a positive mediator between TT and AD in both sexes and between TE2 and AD in males (p < 0.001), but a negative mediator between TT and current drinking in controls (both sexes) and AD males (p < 0.001).

CONCLUSIONS

Testosterone and estradiol levels are altered in males and females with AD distinctly regardless of current drinking frequency. SHBG may play a critical role in these associations.

The effects of alcohol on testosterone synthesis in men: a review

INTRODUCTION

Testosterone concentrations in men decline with advancing age, with low testosterone concentrations being associated with multiple morbidities, an increased risk of early mortality, and a reduced quality of life. The purpose of this study was to examine the effects of alcohol on testosterone synthesis in men by investigating its effects on each level of the hypothalamic-pituitary-gonadal axis.

AREAS COVERED

Acute consumption of a low-to-moderate amount of alcohol increases testosterone concentrations in men, while consumption of a large volume of alcohol is associated with a reduction in serum testosterone concentrations. Elevated testosterone concentrations result from the increased activity of detoxification enzymes in the liver. Conversely, the primary mechanisms of action involved in the reduction of testosterone are increased hypothalamic-pituitary-adrenal axis activity, inflammation, and oxidative stress. When alcohol is consumed in excess, particularly chronically, it negatively affects testosterone production in men.

EXPERT OPINION

Since testosterone is an important component of men's health and wellbeing, current levels of alcohol consumption in many countries of the world require urgent attention. Elucidating the relationship between alcohol consumption and testosterone may be useful in identifying strategies to attenuate the testosterone-reducing effects of excessive or chronic alcohol consumption.

Recreational Drug Misuse and Its Potential Contribution to Male Fertility Levels' Decline: A Narrative Review

Recreational drug intake may be associated with a range of medical untoward consequences, including male infertility. However, as the related evidence is still limited, the main outcome of this review is to provide a better understanding of the existence of any association between recreational drug misuse and male fertility levels' decline. Whilst searching the MEDLINE/PubMed, a comprehensive overview of the literature regarding male infertility and substances of abuse (e.g., phytocannabinoids, opiates/opioids, stimulants, 'herbal highs', psychedelics, and 'novel psychoactive substances) was here undertaken. Due to the paucity of robust, high-quality, empirical, human studies, a narrative strategy was here preferred over a systematic approach. Relevant data are qualitatively analyzed and presented in a table. Although most available evidence is in support of a detrimental role of cannabis on human spermatogenesis, a few remaining studies failed to document any effect of this drug on seminal quality, and it is not clear to which extent this drug impacts fertility rates/time to pregnancy. The current understanding of the impact of opiate-, cocaine- and amphetamine/stimulant-misuse on human reproduction is widely unknown, and most studies dealing with this matter represent only an extrapolation of data derived from specific clinical circumstances. Although the message of 'no smoking, no alcohol and no street drugs' should always be offered as good health advice to all patients seeking medical help for fertility issues, robust scientific clinical evidence in support of a direct detrimental impact of recreational drugs on spermatogenesis is scant to date.

Use of Psychoactive Substances during the Perinatal Period: Guidelines for Interventions during the Perinatal Period from the French National College of Midwives

Based on their clinical practice and an extensive review of the literature, the authors propose a framework of procedures to be followed to provide services to all women of childbearing age who use psychoactive substances (alcohol, cannabis, cocaine, amphetamines, and opioids), especially during pregnancy or during the postpartum and breastfeeding periods, in view of their individual situations and environmental contexts.

[Impact of lifestyle and environmental factors on male reproductive health]

The identification of potential environmental hazards is of clinical relevance for the diagnosis of male infertility. Knowledge about these factors will improve prevention of fertility disorders. Apart from drugs or factors related to lifestyle such as alcohol and tobacco smoke, various environmental and occupational agents, both chemical and physical, may impair male reproduction. Reproductive toxicity may evolve at the hypothalamic-pituitary, testicular, or posttesticular level; endpoints comprise deterioration of spermatogenesis and sperm function as well as endocrine disorders and sexual dysfunction. However, due to the complex regulation of the male reproductive system, information regarding single exogenous factors and their mechanisms of action in humans is limited. This is also due to the fact that extrapolation of results obtained from experimental animal or in vitro studies remains difficult. Nevertheless, the assessment of relevant exposures to reproductive toxicants should be carefully evaluated during diagnostic procedures of andrological patients.

Association of healthy beverage index with circadian rhythm and quality of sleep among overweight and obese women: a cross-sectional study

PURPOSE

Circadian rhythm is a behavioral, physiological, and molecular change with a cycle length of approximately 24 h. Changes to the circadian rhythm can result in sleep difficulty. The healthy beverage index (HBI) is a holistic concept for evaluating the quality of overall beverage intake and its association with health-related outcomes in nutritional epidemiological studies. This study aimed to assess the relationship of HBI with circadian rhythm and sleep quality among overweight/obese women.

METHODS

The current study was conducted among 208 overweight and obese women between 18-48 years in Tehran, Iran. We evaluated potential HBI with a valid food frequency questionnaire. Following standard procedures, trained personnel assessed anthropometric measures, blood samples, and other baseline characteristics. The Pittsburgh Sleep Quality Index and the morning-eveningness questionnaire were applied to evaluate sleep quality and circadian rhythm respectively.

RESULTS

The mean (SD) BMI for this study was 30.8 (4.2) kg/m². We observed that subjects in the least tertile had significantly high levels of triglyceride (p = 0.04) and low-density lipoprotein (p = 0.009). High-density lipoprotein was significantly different across the tertiles (p = 0.003). After adjusting for potential covariates, subjects in the second tertile of HBI had 5.07 odds of having the worst quality of sleep as compared to those in the third tertile, p < 0.05. We also observed a significant inverse association between the HBI and the "moderately evening type" participants (OR 0.86; 95% CI 0.68-0.99; p: 0.02) after adjusting for potential confounders.

CONCLUSION

Healthy beverage consumption may have the potential of improving sleep quality among overweight and obese subjects.

LEVEL OF EVIDENCE

Level IV, evidence obtained from a descriptive study.

Smoking and Its Consequences on Male and Female Reproductive Health

Smoking contributes to the death of around one in 10 adults worldwide. Specifically, cigarettes are known to contain around 4000 toxins and chemicals that are hazardous in nature. The negative effects of smoking on human health and interest in smoking-related diseases have a long history. Among these concerns are the harmful effects of smoking on reproductive health. Thirteen percent of female infertility is due to smoking. Female smoking can lead to gamete mutagenesis, early loss of reproductive function, and thus advance the time to menopause. It has been also associated with ectopic pregnancy and spontaneous abortion. Even when it comes to assisted reproductive technologies cycles, smokers require more cycles, almost double the number of cycles needed to conceive as non-smokers. Male smoking is shown to be correlated with poorer semen parameters and sperm DNA fragmentation. Not only active smokers but also passive smokers, when excessively exposed to smoking, can have reproductive problems comparable to those seen in smokers. In this book chapter, we will approach the effect of tobacco, especially tobacco smoking, on male and female reproductive health. This aims to take a preventive approach to infertility by discouraging smoking and helping to eliminate exposure to tobacco smoke in both women and men.

Impact of heavy alcohol consumption and cigarette smoking on sperm DNA integrity

The purposes of the presents study were to investigate the impact of alcohol consumption and cigarette smoking on semen parameters and sperm DNA quality, as well as to determine whether tobacco smoking, or alcohol consumption causes more deterioration of sperm quality. Two hundred and eleven semen samples of men were included in this study. Four groups were studied: heavy smokers (N = 48), heavy drinkers (N = 52), non-smokers (n = 70), and non-drinkers (n = 41). Semen parameters were determined according to WHO guidelines, protamine deficiency assessed by chromomycin (CMA3) staining, and sperm DNA fragmentation (sDF) evaluated by TUNEL assay. Sperm parameters were significantly higher in non-smokers versus smokers and in non-drinkers versus drinkers (p < 0.005). However, protamine deficiency and sDF were significantly lower in non-smokers versus smokers and in non-drinkers versus drinkers (p < 0.0001). No significant difference in the semen analysis parameters was observed between heavy smokers and heavy drinkers (semen volume: 3.20 ± 1.43 vs. 2.81 ± 1.56 ml, semen count: 65.75 ± 31.32 vs. 53.51 ± 32.67 mill/ml, total motility: 24.27 ± 8.18 vs. 23.75 ± 1.75%, sperm vitality: 36.15 ± 18.57 vs. 34.62 ± 16.65%, functional integrity: 41.56 ± 18.57 vs. 45.96 ± 17.98% and the morphologically normal spermatozoa: 28.77 ± 11.82 vs. 27.06 ± 13.13%, respectively). However, protamine deficiency was significantly higher among drinkers than smokers (37.03 ± 9.75 vs. 33.27 ± 8.56%, p = 0.020). The sDF was also significantly higher among drinkers than smokers (22.37 ± 7.60 vs. 15.55 ± 3.33%, p < 0.0001). Thus, cigarette smoking, and heavy alcohol intake can deteriorate sperm quality. However, alcohol consumption deteriorates sperm maturity and damages DNA integrity at significantly higher rates than cigarette smoking.

The current situation and future directions for the study on time-to-pregnancy: a scoping review

Introduction

As problems associated with infertility and population aging increase, there is a growing interest in the factors that cause a decline in human fertility. Time-to-pregnancy (TTP) is a good indicator with which to reflect human fecundability. Here, we present a comprehensive overview of this topic.

Methods

Relevant qualitative and quantitative studies were identified by searching the Web of science and PubMed electronic databases. We included all literature, written in English, from inception to the 10th April 2021 providing the focus was on TTP. We conducted a narrative synthesis using thematic analysis.

Results

Traditional TTP-related study protocols include prospective and retrospective cohorts that provide a wealth of data to reveal potential influences on TTP. Thus far, a variety of factors have been shown to be associated with TTP in couples preparing for pregnancy, including basic demographic characteristics, menstrual status, chronic disease status, environmental endocrine disruptor exposure, and lifestyles. However, there are inevitable epidemiological bias in the existing studies, including recall bias, selection bias and measurement bias. Some methodological advances have brought new opportunities to TTP research, which make it possible to develop precision interventions for population fertility. Future TTP studies should take advantage of artificial intelligence, machine learning, and high-throughput sequencing technologies, and apply medical big data to fully consider and avoid possible bias in the design.

Conclusion

There are many opportunities and future challenges for TTP related studies which would provide a scientific basis for the “precise health management” of the population preparing for pregnancy.

As the problems of infertility and population aging increase, there is a growing interest in the factors that cause a decline in human fertility. Time-to-pregnancy (TTP) is a good indicator with which to reflect human fecundability, and a longer TTP is known to reflect a reduction in fertility. Many original studies, with different designs, have used TTP to explore the factors that might influence fertility, including basic demographic characteristics, chronic disease status, environmental endocrine disruptor exposure, and lifestyles. However, much of the existing evidence is inconsistent and limited by various types of bias. This review provides a synopsis of recent TTP studies, and highlights new opportunities and future challenges.

Lutein Can Alleviate Oxidative Stress, Inflammation, and Apoptosis Induced by Excessive Alcohol to Ameliorate Reproductive Damage in Male Rats

Chronic excessive alcohol intake may lead to male reproductive damage. Lutein is a carotenoid compound with antioxidant activity. The purpose of this study was to observe the effect of lutein supplementation on male reproductive damage caused by excessive alcohol intake. In this study, an animal model of excessive drinking (12 mL/(kg.bw.d)) for 12 weeks was established and supplemented with different doses of lutein (12, 24, 48 mg/(kg.bw.d)). The results showed that the body weight, sperm quality, sex hormones (FSH, testosterone), and antioxidant markers (GSH-Px) decreased significantly, while MDA and inflammatory factors (IL-6, TNF-α) increased significantly in the alcohol model group when compared to the normal control group. After 12 weeks of high-dose lutein supplementation with 48mg/(kg.bw.d), the spermatogenic ability, testosterone level, and the activity of marker enzymes reflecting testicular injury were improved. In addition, high-dose lutein supplementation downregulated the NF-κB and the pro-apoptosis biomarkers (Bax, Cytc and caspase-3), whereas it upregulated the expression of Nrf2/HO-1 and the anti-apoptotic molecule Bcl-2. These findings were fully supported by analyzing the testicular histopathology and by measuring germ cell apoptosis. In conclusion, lutein protects against reproductive injury induced by excessive alcohol through its antioxidant, anti-inflammatory, and anti-apoptotic properties.

Local and Systemic Oxidative Stress Biomarkers for Male Infertility: The ORION Study

Infertility problems occur in around 10% of all couples worldwide, with male-factor infertility as the sole contributor in 20–30% of these cases. Oxidative stress (OS) is suggested to be associated with the pathophysiology of male infertility. In spermatozoa, OS can lead to damage to the cell membrane, resulting in disruption of DNA integrity and a decrease in motility. Established biomarkers for OS include free thiols and malondialdehyde (MDA), both representing different components of the reactive species interactome (RSI). This exploratory study aimed to investigate seminal plasma-free thiol and MDA levels in relation to semen parameters as defined by the World Health Organization (WHO) to determine if these markers are adequate to define local OS status. Furthermore, this study investigated if there is a relation between systemic and local OS status by comparing seminal concentrations of free thiol (R-SH, sulfhydryl groups, representing the extracellular redox status) and MDA (lipid peroxidation product) levels to those measured in serum. Free thiol and MDA measurements in both serum and semen plasma were performed in 50 males (18–55 y) of couples seeking fertility treatment. A significant positive correlation was found between seminal plasma-free thiol levels and sperm concentration and progressive motility (r = 0.383, p = 0.008 and r = 0.333, p = 0.022, respectively). In addition, a significant positive correlation was found between MDA levels in seminal plasma and sperm concentration (r = 0.314, p = 0.031). This study supports that seminal plasma-free thiols may be promising as local OS biomarkers. No associations were observed between local and systemic OS biomarker concentrations.

Physical activity and sperm quality: influence in sperm donors

PURPOSE

To ascertain whether physical activity (PA) is associated with better sperm quality in sperm donors.

METHODS

A prospective case-control study was designed in an IVF center setting. A total of 207 sperm donation candidates from a relatively small geographical area were included in the study with no intervention. Donor candidates were subjected to conventional sperm analysis according to WHO criteria. Moreover, they answered a standardized questionnaire regarding their last week PA (IPAQ), with PA expressed in metabolic equivalents (METs)-min/week. Donors were classified into 4 groups: low, moderate, high and very high PA. Specific sports were included in the questionnaire. Semen samples from 43 accepted donors were used in artificial insemination by donor (AID) and IVF. The fertilization rates (FR) and pregnancy rates (PR) were studied.

RESULTS

Semen volume, sperm concentration, progressive spermatozoa, non-progressive spermatozoa, total motile progressive spermatozoa and sperm morphology were similar in the four PA groups. No correlation between various semen parameters studied and METs was found. Running or cycling > 1 h/week did not influence sperm parameters. The AID PR was similar in the different PA groups. However, in IVF the mean donor FR was significantly higher in the high PA group and in the very high PA group.

CONCLUSIONS

No detrimental effect was associated with PA, or even very high PA, regarding conventional sperm parameters. Moreover, a better FR was associated with high and very high PA in IVF cycles, which merits more studies.

Addiction and human male fertility: A systematic review and a critical appraisal

BACKGROUND

Addiction is a global problem that has many negative consequences on human health as well as the quality of life.

OBJECTIVES

This review aimed to assess the effect of addiction on human male fertility.

METHODS

A systematic review was conducted on various electronic sites.

RESULTS

The initial literature search identified a total of 5239 articles in all searched databases. After removing duplicates and application of inclusion/exclusion criteria,177 were potential articles, 112 were omitted because no direct relevance was encountered. Finally, 65 studies were retained for review. They were classified according to the type of addiction into; opioids and cannabinoids (18 articles), alcohol (7 articles), cocaine (2 articles), Androgenic Anabolic steroids AAS (15 articles), tobacco (10 articles) and caffeine (13 articles). Most of these recruited articles demonstrated a negative impact of the addressed substance on male fertility with variable levels of evidence.

CONCLUSIONS

It was concluded that addiction harms human male fertility that should be put into consideration. More future studies are needed after a proper methodological and statistical approach, including logistic regression analysis, to predict the effect of a specific substance on human male fertility. This article is protected by copyright. All rights reserved.

Diet Quality Scores and Asthenoteratozoospermia Risk: Finding From a Hospital-Based Case–Control Study in China

Objective

We aimed to examine associations of diet quality scores, including the dietary approaches to stop hypertension (DASH), alternate Healthy Eating Index (AHEI), and Chinese Healthy Eating Index (CHEI) with asthenoteratozoospermia risk in China.

Methods

Among 254 cases and 633 controls in a hospital-based case–control study in Shenyang, Liaoning Province, China, DASH, AHEI, and CHEI were calculated using a validated food frequency questionnaire. Asthenotetrazoospermia was evaluated according to World Health Organization guidelines. Unconditional multiple logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between quality diet scores and asthenoteratozoospermia risk.

Results

We found that the CHEI score was inversely associated with asthenoteratozoospermia risk, with ORs of 0.59 (95% CI 0.39, 0.88) and 0.59 (95% CI 0.39, 0.88) for the 2nd and 3rd tertiles vs. the 1st tertile, respectively (P trend < 0.05). In addition, our data indicated that each standard deviation increase in CHEI, AHEI-2010, and DASH score was associated with 19, 13, and 17% decreased risk of asthenoteratozoospermia, respectively.

Conclusion

Our findings suggest that higher adherence to the CHEI, AHEI-2010, and DASH diet quality scores may reduce the risk of asthenoteratozoospermia, especially for younger participants.

Exploring male perceptions regarding the need to engage in preconception care - a mixed-method study amongst Dutch (prospective) fathers

PURPOSE

While most preconception care (PCC) interventions are aimed at women, men are also in need of PCC to reduce risk factors affecting the spermatozoa quality. The objective of this study is to explore male perceptions regarding the need to engage in PCC.

MATERIALS AND METHODS

In a mixed-method cross-sectional study, 229 men participated with a questionnaire and 14 individual semi-structured interviews were conducted. Questionnaires data were analysed using multiple regression analyses. The interviews were analysed using thematic analyses.

RESULTS

Most men did not retrieve preconceptional information (n = 135; 59.0%) nor visited a preconceptional consult (n = 182; 79.5%). Men who categorised their preconceptional lifestyle as unhealthy (score ≤6 out of 10) less often retrieved information (adjusted OR 0.36 [95% CI 0.14-0.93]) than men with a healthy preconceptional lifestyle. While several men expressed their fear for infertility, this did not lead to an increased uptake of PCC as men felt they were healthy enough already.

CONCLUSION

Despite high awareness of the positive influence of a healthy lifestyle, the perceived need for preparing for pregnancy among men remains low. Tailoring preconceptional information towards male needs provides a window of opportunity to improve men's reproductive health and possibly the health of future generations.

Impact of Alcohol Consumption on Male Fertility Potential: A Narrative Review

Alcohol abuse disorder is a serious condition, implicating more than 15 million people aged 12 years and older in 2019 in the United States. Ethanol (or ethyl alcohol) is mainly oxidized in the liver, resulting in the synthesis of acetaldehyde and acetate, which are toxic and carcinogenic metabolites, as well as in the generation of a reductive cellular environment. Moreover, ethanol can interact with lipids, generating fatty acid ethyl esters and phosphatidylethanol, which interfere with physiological cellular pathways. This narrative review summarizes the impact of excessive alcohol consumption on male fertility by describing its metabolism and how ethanol consumption may induce cellular damage. Furthermore, the impact of alcohol consumption on hormonal regulation, semen quality, and genetic and epigenetic regulations is discussed based on evidence from animal and human studies, focusing on the consequences on the offspring. Finally, the limitations of the current evidence are discussed. Our review highlights the association between chronic alcohol consumption and poor semen quality, mainly due to the development of oxidative stress, as well as its genotoxic impact on hormonal regulation and DNA integrity, affecting the offspring’s health. New landscapes of investigation are proposed for the identification of molecular markers for alcohol-associated infertility, with a focus on advanced OMICS-based approaches applied to the analysis of semen samples.

Sex bias in alcohol research: A 20-year comparative study

We aimed to assess the sex-inclusive and sex-based analysis bias in alcohol research for the past 20 years. Data were abstracted from 2988 original research articles published from 2000 through 2019 in 51 representative journals across 9 biomedical disciplines. An analysis in 5-year intervals revealed that the percentage of studies using participants of both sexes was significantly higher between 2015 and 2019 than between 2000 and 2014. When stratified, clinical studies showed a higher percentage of both-sex studies compared to basic studies using animals. The reasons for the use of single-sex cohorts mainly included insufficient participant numbers and misconceptions surrounding the hormonal variability of females. Implementation of the NIH SABV policy promoted the ratio of NIH-funded papers with sex-based analyses. In conclusion, sex bias in alcohol-related biomedical studies has improved over the past 20 years, particularly after the implementation of the SABV policy. Although clinical studies increasingly included sex-based analysis, basic studies were biased towards the use of males.

The impact of alcohol on the male reproductive system

Although alcohol has been consumed by humans for centuries, its effect on reproductive function is still not fully understood. Numerous studies have examined the effects of alcohol on ejaculate parameters and male fertility. This article provides an overview of the main preclinical and clinical studies. Studies in experimental animals have shown that ethanol-rich diets cause spermatogenesis abnormalities, a variety of abnormalities involving different parts of the reproductive tract, and a decreased frequency of fertilization in murine oocytes. These effects quickly disappeared with the cessation of alcohol use. Most of the studies examining the effects of alcohol on men have shown a negative effect on ejaculate parameters. An association of hypogonadism and low or elevated gonadotropin levels has been reported, suggesting a combined central and peripheral damaging effect of ethanol. Thus, alcohol consumption has a pronounced negative effect on ejaculate parameters, which can be reversible upon cessation of alcohol consumption.

Temporal trends in semen concentration and count among 327 373 Chinese healthy men from 1981 to 2019: a systematic review

STUDY QUESTION

Are there temporal trends of sperm concentration (SC) and total sperm count (TSC) in Chinese healthy males from 1981 to 2019?

SUMMARY ANSWER

Our result indicated a temporal decrease in SC and TSC among 327 373 healthy Chinese men in the recent four decades.

WHAT IS KNOWN ALREADY

A review of 61 papers reported a temporal decline in SC and TSC from 1938 to 1990. This trend was later confirmed by a systematic review of 185 published papers from 1981 to 2013. However, the majority of the included individuals were from western countries. In China, whether SC and TSC have declined remains controversial.

STUDY DESIGN, SIZE, DURATION

This systematic review of published articles used data extracted from Pubmed, Science Direct, Embase, China-National-Knowledge-Infrastructure (CNKI) and Wanfang Data to assess changes in SC and TSC in China from 1981 to 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 111 studies including 327 373 individuals who provided semen samples from 1981 to 2019 were extracted for the present analysis. Study selection and data extraction were performed by two independent researchers. The trends in SC and TSC were analysed using liner-regression and meta-regression before and after adjusting for potential covariates. Moreover, subgroups, categorised based on geographic region, fertility status or recruitment source, were also analysed.

MAIN RESULTS AND THE ROLE OF CHANCE

SC declined significantly (slope liner-regression = -0.748 million/ml/year; P = 0.005; slope meta-regression = -0.824 million/ml/year; P < 0.001) between 1981 and 2019 in China. Trends for TSC was similar to that for SC (slope liner-regression = -2.073 million/year; P = 0.032; slope meta-regression = -2.188 million/year; P = 0.003). In subgroup meta-regression analyses, males with definite fertility had continuous declines in SC (slope northern group=-2.268, P = 0.009; slope southern group=-1.014, P = 0.009) and TSC (slope northern group=-9.675, P = 0.010; slope southern group=-3.215, P = 0.042). However, in the unselected group, where fertility status was unknown, the obvious downward trend in SC was only seen in males from Northern regions (slope = -0.836, P = 0.003). Another subgroup analysis demonstrated that obvious decreases in SC (slope = -1.432, P < 0.001) and TSC (slope=-4.315, P = 0.001) were only seen in volunteer groups but not in pre-pregnancy examination groups and other recruitment groups. The results changed minimally in multiple sensitivity analyses.

LIMITATIONS, REASONS FOR CAUTION

The validity of the meta-analysis results was limited mainly by the quality of the included studies. Additionally, our study spanned many decades and the recommended criteria for some semen parameter assessments have significantly changed, which may bring about some unavoidable bias. Moreover, the data remain insufficient especially in some provinces of China.

WIDER IMPLICATIONS OF THE FINDINGS

The present study is the first study to report significant decreases in SC and TSC in 327 373 healthy Chinese men between 1981 and 2019, indicating a serious reproductive health warning. Further studies on the causes of the declines are urgently needed.

STUDY FUNDING/COMPETING INTEREST(S)

D.Z. is supported by the National Natural Science Funding of China, Natural Science Funding of Shaanxi Province, Science Funding of Health Department, Shaanxi Province, Fundamental Research Funds for the Central University and the Project of Independent Innovative Experiment for Postgraduates in Medicine in Xi'an Jiaotong University. The authors have no conflicts of interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Decline of semen quality over the last 30 years in Uruguay

BACKGROUND

Over the last years, there has been an increasing concern about a global decline in men's fertility. Specifically, some evidence indicates that sperm quality has decreased over the last years. However, reports showing the changes in sperm quality with time are inconsistent. Part of the contradictions between studies is attributed to geographical differences. Surprisingly, few studies include data from South American countries, creating a bias in the conclusions. This study aims to determine how sperm quality has evolved over the past 30 years in Uruguay. For this purpose, 317 medical records from allegedly healthy sperm donor candidates, aged between 18 and 36 years old, who voluntarily requested to be considered as sperm donors between 1988 and 2019, were analyzed. The studied variables were the following sperm parameters: semen volume, sperm cell concentration, total sperm number, progressive motility, vitality, and sperm morphology. A correlative statistical analysis was performed between seminal parameter values and the year data were collected.

RESULTS

We found a statistically significant decrease in sperm concentration and normal sperm morphology during the studied period. There was no decrease in vitality, seminal volume, and total progressive motility. Semen parameters were not associated with tobacco, drugs, or alcohol consumption.

CONCLUSIONS

We conclude that the sperm quality of donor candidates in Uruguay decreased during this period. Further studies should be carried out to verify the occurrence of this phenomenon in the general population and find its possible causes.

Interactive Effects of Unhealthy Lifestyle Behaviors on Testicular Function among Healthy Adult Men: A Cross-Sectional Study in Taiwan

Recently, the role of lifestyle factors in testicular function has developed into a growing area of interest. Based on cross-sectional data on 3283 Taiwanese men, we investigated whether interactive effects of unhealthy lifestyle behaviors were associated with testicular function. The men were recruited from a private screening institute between 2009 and 2015. Lifestyle behaviors (smoking, alcohol drinking, physical activity (PA), sleeping habits, and diet) were obtained by a validated self-reported questionnaire. The men provided a semen sample and had blood drawn for sex hormone measurement. Men who smoked and drank had higher testosterone (T) levels (β = 0.81, p < 0.001) than those who neither smoked nor drank. Men who smoked and had high Western dietary pattern scores had higher T levels-by 0.38 ng/mL (p = 0.03). Those who drank and did not get enough sleep or had high Western dietary pattern scores had elevated T levels-by 0.60 ng/mL (p = 0.005) or 0.45 ng/mL (p = 0.02), respectively. Light PA and insomnia were associated with decreased T levels-by 0.64 ng/mL (p < 0.001). Those who smoked and drank or had light PA or had high Western dietary pattern scores had lower normal sperm morphologies (NSMs)-by 2.08%, 1.77%, and 2.29%, respectively. Moreover, drinkers who had high Western dietary pattern scores had higher sperm concentrations-by 4.63 M/mL (p = 0.04). Awareness and recognition of the long-term impact of lifestyle behaviors and better lifestyle choices may help to optimize the chance of conception amongst couples.

Synthesis of a green bigel using cottonseed oil/cannabis oil/alginate/ferula gum for quercetin release: Synergistic effects for treating infertility in rats

Although therapeutic effect of quercetin (Quer) was reported on non-alcoholic fatty liver disease (NAFLD), destructive effects have been shown on male fertility due to its pro-oxidative properties. On the other hand, NAFLD impairs germ cells to produce sperm and leads to male infertility. Herein, a biocompatible and green bigel was designed for Quer delivery to prevent infertility induced by NAFLD as the increasing complications. Bigels were prepared using cottonseed oil/cannabis oil/alginate/ferula gum and optimized by the mixture design method. NAFLD was induced by 58% of dietary calorie as lard and 42 g/l fructose for 16 weeks in Sprague-Dawley rats. So on animals received 2 mg/kg Quer loaded on bigels, free bigels, or free Quer for 45 days as daily gavage. Semen was analyzed, followed by the assessment of DNA integrity. Count, motility, and normal morphology reached the healthy control group at the bigel-Quer-treated one. Moreover, all of these parameters were significantly higher in the bigel-Quer group than the Quer and bigel, alone. The percent of sperms with head and tail abnormality decreased considerably in the bigel-Quer group compared with the Quer, free bigel, and NAFLD groups. Serum testosterone levels significantly increased and reached the healthy control group in the bigel-Quer group. DNA fragmentation of sperm significantly decreased in the bigel-Quer group (p < 0.05). The bigel showed synergistic effects with Quer for treating infertility in rats with NAFLD.

Is there a temporal trend in semen quality in Belgian candidate sperm donors and in sperm donors' fertility potential from 1995 onwards?

BACKGROUND

A recent meta-regression analysis reported a temporal trend in sperm count showing a significant decline in sperm count between 1973 and 2011. This decline is thought to affect fecundity. Moreover, semen quality is considered of key interest to public health given its association with all-cause male morbidity/mortality. The issue requires ongoing investigation due to geographical variation in semen quality and methodological errors in semen analysis.

OBJECTIVE

To study whether there is a temporal trend in semen quality in Belgian candidate sperm donors and in sperm donors' fertility potential.

MATERIALS AND METHODS

Retrospective analysis of samples provided by 439 candidate donors and pregnancy outcome in acceptors over a period of 23 years.

RESULTS

A total of 807 specimens from 439 candidate donors were examined from January 1995 to December 2017 (Table S1). Sub-analyses performed with regard to TSC from 2010 onwards (weighing) revealed a significant negative trend (R² =-0.033; β=-0.18; CI: -0.16 to 0.07; p < 0.05). We found a statistically significant association between year of donation and morphology (R² = 0.036; β= -0.19; CI: -0.26 to -0.08; p < 0.0001). The mean (±SD) clinical pregnancy rate per effective donor recruited (n = 104), defined as the number of women with a clinical pregnancy, per number of women who initiated treatment with a donor's spermatozoa, was 68.5 (± 24.9) %. This measure did not show a significant change in function of year of donation.

DISCUSSION

Candidate sperm donors represent a select group of men; as such, these results are not to be interpreted as representative for the general population.

CONCLUSION

The study did not show a significant change in sperm concentration or fertility potential in sperm donors over a period of 23 years. However, a negative trend was found for TSC from 2010 onwards. Also, the results show a significant decrease in ideal morphology over time.

Male infertility due to testicular disorders

CONTEXT

Male infertility is defined as the inability to conceive following 1 year of regular unprotected intercourse. It is the causative factor in 50% of couples and a leading indication for assisted reproductive techniques (ART). Testicular failure is the most common cause of male infertility, yet the least studied to date.

EVIDENCE ACQUISITION

The review is an evidence-based summary of male infertility due to testicular failure with a focus on etiology, clinical assessment, and current management approaches. PubMed-searched articles and relevant clinical guidelines were reviewed in detail.

EVIDENCE SYNTHESIS/RESULTS

Spermatogenesis is under multiple levels of regulation and novel molecular diagnostic tests of sperm function (reactive oxidative species and DNA fragmentation) have since been developed, and albeit currently remain as research tools. Several genetic, environmental, and lifestyle factors provoking testicular failure have been elucidated during the last decade; nevertheless, 40% of cases are idiopathic, with novel monogenic genes linked in the etiopathogenesis. Microsurgical testicular sperm extraction (micro-TESE) and hormonal stimulation with gonadotropins, selective estrogen receptor modulators, and aromatase inhibitors are recently developed therapeutic approaches for men with the most severe form of testicular failure, nonobstructive azoospermia. However, high-quality clinical trials data is currently lacking.

CONCLUSIONS

Male infertility due to testicular failure has traditionally been viewed as unmodifiable. In the absence of effective pharmacological therapies, delivery of lifestyle advice is a potentially important treatment option. Future research efforts are needed to determine unidentified factors causative in "idiopathic" male infertility and long-term follow-up studies of babies conceived through ART.

Association of Testosterone-Related Dietary Pattern with Testicular Function among Adult Men: A Cross-Sectional Health Screening Study in Taiwan

Diets could play an important role in testicular function, but studies on how adherence to the dietary patterns influences human testicular function in Asian countries are scarce. Herein, we examined the association between testosterone-related dietary patterns and testicular function among adult men in Taiwan. This cross-sectional study recruited 3283 men who attended a private medical screening program from 2009 to 2015. Testosterone-related dietary pattern was generated by the reduced rank regression (RRR) method. The association between adherence to quartile of dietary pattern scores with sex hormones (testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2)) and sperm quality (sperm concentration (SC), total sperm motility (TSM), progressive motility (PRM), and normal sperm morphology (NSM)) were examined by multivariable linear regression. Hemoglobin (β = 0.57, p < 0.001), hematocrit (β = 0.17, p = 0.002), triglyceride (β = −0.84, p < 0.001), HDL-cholesterol (β = 3.58, p < 0.001), total cholesterol to HDL-cholesterol ratio (β = −0.78, p < 0.001), and uric acid (β = −10.77, p < 0.001) were highly correlated with testosterone levels. Therefore, these biomarkers were used to construct a testosterone-related dietary pattern. Highest adherence (Q4) to dietary pattern scores were negatively associated with lower testosterone in the pooled analysis (β = −0.89, p = 0.037) and normal-weight men (β = −1.48, p = 0.019). Likewise, men in the Q4 of the dietary pattern had lower SC (β = −5.55, p = 0.001) and NSM (β = −2.22, p = 0.007) regardless of their nutritional status. Our study suggesting that testosterone-related dietary pattern (rich in preserved vegetables or processed meat or fish, deep-fried foods, innards organs, rice or flour products cooked in oil, and dipping sauce, but low in milk, dairy products, legumes, or beans, and dark or leafy vegetables) was associated with a poor testicular function.

Evaluating the genetic effects of sex hormone traits on the development of mental traits: a polygenic score analysis and gene-environment-wide interaction study in UK Biobank cohort

OBJECTIVE

To evaluate the genetic effects of sex hormone traits on the development of mental traits in middle-aged adults.

METHODS

The SNPs associated with sex hormone traits were derived from a two-stage genome-wide association study (GWAS). Four sex hormone traits were selected in the current study, including sex hormone-binding globulin (SHBG), testosterone, bioavailable testosterone and estradiol. The polygenic risk score (PRS) of sex hormone traits were calculated from individual-level genotype data of the United Kingdom (UK) Biobank cohort. We then used logistic and linear regression models to assess the associations between individual PRS of sex hormone traits and the frequency of alcohol consumption, anxiety, intelligence and so on. Finally, gene-environment-wide interaction study (GEWIS) was performed to detect novel candidate genes interacting with the sex hormone traits on the development of fluid intelligence and the frequency of smoking and alcohol consumption by PLINK2.0.

RESULTS

We observed positive association between SHBG and the frequency of alcohol consumption (b = 0.0101, p = 3.84 × 10-11) in middle-aged males and females. In addition, estradiol was positively associated with the frequency of alcohol consumption (b = 0.0128, p = 1.96 × 10-8) in middle-aged males. Moreover, bioavailable testosterone was associated with the fluid intelligence (b = - 0.0136, p = 5.74 × 10-5) in middle-aged females. Finally, GEWIS identified one significant loci, Tenascin R (TNR) (rs34633780, p = 3.45 × 10-8) interacting with total testosterone for fluid intelligence.

CONCLUSION

Our study results support the genetic effects of sex hormone traits on the development of intelligence and the frequency of alcohol consumption in middle-aged adults in UK.

Influence of Lifestyle and Environmental Factors on Semen Quality in Ghanaian Men

Introduction

Male infertility is known to contribute about half of all infertility cases. In Ghana, the prevalence of male infertility is higher (15.8%) than in females (11.8%). Sperm quality is associated with the likelihood of pregnancy and known to be the cause of male fertility problems 90% of the time. Exposure to certain environmental factors reduces semen quality in men. The study examined the effects of environmental and lifestyle factors on semen quality in Ghanaian men.

Materials and Methods

This was a cross-sectional study involving 80 apparent healthy adult males in their reproductive age. Participants were males referred to the laboratory (Immunology Unit of the Korle-Bu Teaching Hospital) for semen analysis test and/or culture and sensitivity. Participants were made to fill out a questionnaire which entailed selected environmental factors (accidents or trauma, exposure to chemicals, radiation, and heat) and lifestyle habits (including alcohol consumption, smoking, and whether participants sat more or less than 4 hours per day). Semen samples were then collected by masturbation into sterile containers and analysed in accordance with WHO guidance for semen analysis within 60 minutes after ejaculation and collection.

Results

About 69% of participants had semen pH within the normal range compared to 15% whose pH were lower than 7.2. There was a significantly high number of immotile sperm cells (p value = 0.017) in participants who sat for more than 4 hours as compared to those that sat for less than 4 hours in a day. Active sperm motility and viability showed significant increase (p value = 0.002 and 0.009, respectively) in participants who kept their cell phones in their side pockets. Smoking produced a twofold decrease in sperm count as smokers had a significantly lower sperm count (12.28 ± 10.95 × 10⁶/ml) compared to the smoke-free (23.85 ± 22.14 × 10⁶/ml). For exposure to STDs, no significant differences were recorded among study groups concerning semen quality.

Conclusion

Sperm quality in Ghanaian men is associated with lifestyle habits. Smoking and sitting for long hours influenced sperm motility and count, respectively. Knowledge of the factors that influence sperm quality in this geographical region can contribute to informed decisions on effective management of infertility in Ghanaian men.

Regional difference in semen quality of young men: a review on the implication of environmental and lifestyle factors during fetal life and adulthood

The prevalence of low semen quality and the incidence of testicular cancer have been steadily increasing over the past decades in different parts of the World. Although these conditions may have a genetic or epigenetic origin, there is growing evidence that multiple environmental and lifestyle factors can act alone or in combination to induce adverse effects. Exposure to these factors may occur as early as during fetal life, via the mother, and directly throughout adulthood after full spermatogenic capacity is reached. This review aims at providing an overview of past and current trends in semen quality and its relevance to fertility as well as a barometer of men’s general health. The focus will be on recent epidemiological studies of young men from the general population highlighting geographic variations in Europe. The impact of some lifestyle and environmental factors will be discussed with their role in both fetal life and adulthood. These factors include smoking, alcohol consumption, psychological stress, exposure to electromagnetic radiation, and Endocrine Disrupting Chemicals (EDCs). Finally, the challenges in investigating the influence of environmental factors on semen quality in a fast changing world are presented.

Effects of Paternal Preconception Vapor Alcohol Exposure Paradigms on Behavioral Responses in Offspring

We and others previously reported that paternal preconception chronic ethanol exposure leads to molecular, physiological, and behavioral changes in offspring including reduced ethanol consumption and preference relative to controls. The goal of the present study was to further explore the impact of paternal ethanol exposure on a wide variety of basal and drug-induced behavioral responses in first generation offspring. Adult male mice were exposed to chronic intermittent vapor ethanol or control conditions for 5-6 weeks before being mated with ethanol-naïve females to produce ethanol (E)- and control (C)-sired offspring. E-sired male offspring showed stress hyporesponsivity in a stress-induced hyperthermia assay and E-sired female offspring had reduced binge-like ethanol consumption in a drinking in the dark assay compared to C-sired offspring. E-sired offspring also showed altered sensitivity to a sedative/hypnotic dose of the GABAergic drug midazolam, but not ketamine or ethanol, in a loss of the righting response assay. E-sired offspring did not differ from controls in marble burying, novel object location, novel object recognition, social interaction, bottle-brush, novelty suppressed feeding, prepulse inhibition, every-other-day ethanol drinking, or home cage activity assays. This study adds to a growing body of literature suggesting that like in utero alcohol exposure, paternal preconception alcohol exposure can also have effects that persist and impact behavior of offspring.

Taking fertility for granted - a qualitative exploration of fertility awareness among young, childless men in Denmark and Sweden

Most previous studies about fertility knowledge and attitudes among men have been based on quantitative methods using questionnaires with fixed-choice response options. The aims of this qualitative study were to explore childless young men's reflections on fertility and infertility through semi-structured interviews. Danish (n = 17) and Swedish (n = 12) young childless men aged between 20 and 30 years in their last year of education were interviewed. Data were analysed using qualitative content analysis. Few informants had considered their own fertility, and most were positive towards fertility treatment. The young men had inadequate knowledge about factors that can potentially impair male and female fertility. On average, the young men each mentioned three different factors they believed influence male and female fertility: (i) health behaviour; (ii) factors beyond personal control; and (iii) age. None mentioned sexual transmitted infections (STIs) but most appeared aware of the effect of increasing age on fertility. The results of this study highlight the need for educational strategies to improve young men's knowledge about fertility and the factors that influence it, particularly about the potential adverse effect of STIs on fertility.

Fetal Programming of Semen Quality (FEPOS) Cohort - A DNBC Male-Offspring Cohort

BACKGROUND

Prenatal exposures may contribute to male infertility in adult life, but large-scale epidemiological evidence is still lacking. The Fetal Programming of Semen quality (FEPOS) cohort was founded to provide means to examine if fetal exposures can interfere with fetal reproductive development and ultimately lead to reduced semen quality and reproductive hormone imbalances in young adult men.

METHODS

Young adult men at least 18 years and 9 months of age born to women in the Danish National Birth Cohort living in relative proximity to Copenhagen or Aarhus and for whom a maternal blood sample and two maternal interviews during pregnancy were available were invited to FEPOS. Recruitment began in March 2017 and ended in December 2019. The participants answered a comprehensive questionnaire and underwent a physical examination where they delivered a semen, urine, and hair sample, measured their own testicular volume, and had blood drawn.

RESULTS

In total 21,623 sons fulfilled eligibility criteria of whom 5697 were invited and 1058 participated making the response rate 19%. Semen characteristics did not differ between sons from the Copenhagen and Aarhus clinics. When comparing the FEPOS semen parameters to similar cohorts, the median across all semen characteristics was slightly lower for FEPOS participants, although with smaller variation.

CONCLUSION

With its 1058 young adult men, the FEPOS cohort is the largest population-based male-offspring cohort worldwide specifically designed to investigate prenatal determinants of semen quality. Wide-ranging information on maternal health, lifestyle, socioeconomic status, occupation, and serum concentrations of potential reproductive toxicants during pregnancy combined with biological markers of fertility in their sons collected after puberty allow for in-depth investigations of the 'fetal origins of adult disease hypothesis'.

Impact of psychological stress measured in three different scales on testis function: A cross-sectional study of 1362 young men

BACKGROUND

Studies have reported associations between psychological stress and semen quality, but most have been performed on selected populations using different stress measures. Thus, it is uncertain which stress scale best quantifies the effects of stress on testicular function.

OBJECTIVE

To study the association between three different measures of stress and testicular function in young men.

MATERIAL AND METHODS

In total, 1362 men (median age 19 years) delivered semen and blood samples. They also answered a questionnaire including information from three stress scales: Stress Symptoms, Stressful Life Events and Perceived Stress. Various statistical analyses for associations between stress and testicular function (semen quality and reproductive hormones) were performed.

RESULTS

Perceived Stress was negatively associated with sperm concentration, total count and motility and positively associated with serum FSH. Men with the highest scores (>30 points) had 38% (95% CI 3-84%) lower sperm concentration, 42% (95% CI 5-91%) lower total count and 22% (95% CI 2-32%) lower proportion of motile spermatozoa than men with the lowest scores (0-10 points). For the stress symptoms score, men with highest scores (>95th percentile vs. lower) had lower sperm concentration, total sperm count, motility and serum Inhibin-B/FSH-ratio. Although men with highest stress levels were characterized by an unhealthier lifestyle, adjusting for lifestyle factors did not attenuate results suggesting that the associations between stress and testicular function were not mediated by lifestyle. Stressful Life Events were not associated with testicular function.

DISCUSSION AND CONCLUSION

The linear association between Perceived Stress and semen parameters and lack of dose-response association for the other two stress scales indicated that perceived stress was the most sensitive marker of stress affecting semen quality in young men. The lack of associations between Stressful Life Events and testis function confirmed that the perception of stressful events rather than the stressful event per se matters.

Male alcohol consumption and fecundability

STUDY QUESTION

Does male alcohol consumption affect fecundability?

SUMMARY ANSWER

In data pooled across Danish and North American preconception cohort studies, we found little evidence of an association between male alcohol consumption and reduced fecundability.

WHAT IS KNOWN ALREADY

Experimental and clinical studies have shown that alcohol affects male reproductive physiology, mainly by altering male reproductive hormones and spermatogenesis. However, few epidemiologic studies have examined the association between alcohol consumption and male fertility.

STUDY DESIGN, SIZE, DURATION

Data were collected from two ongoing prospective preconception cohort studies: the Danish 'SnartForaeldre' (SF) study (662 couples) and the North American 'Pregnancy Study Online' (PRESTO) (2017 couples). Participants included in the current analysis were enrolled from August 2011 through June 2019 (SF) and from June 2013 through June 2019 (PRESTO).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible men were aged ≥18 years in SF and ≥21 years in PRESTO, in a stable relationship with a female partner and not using contraception or receiving fertility treatment. In both cohorts, alcohol consumption/serving size was self-reported as number of beers (330 mL/12 oz.), glasses of white or red wine (120 mL/4 oz. each), dessert wine (50 mL/2 oz.) and spirits (20 mL/1.5 oz.). Overall alcohol consumption was categorized as none, 1-5, 6-13 and ≥14 standard servings per week. Total menstrual cycles at risk were calculated using data from female partners' follow-up questionnaires, which were completed every 8 weeks until self-reported pregnancy or 12 menstrual cycles, whichever came first. Analyses were restricted to couples that had been trying to conceive for ≤6 cycles at study entry. Proportional probability regression models were used to compute fecundability ratios (FRs) and 95% confidence interval (CIs). We adjusted for male and female age, female partner's alcohol consumption, intercourse frequency, previous history of fathering a child, race/ethnicity, education, BMI, smoking and consumption of sugar-sweetened beverages and caffeine.

MAIN RESULTS AND THE ROLE OF CHANCE

The cumulative proportion of couples who conceived during 12 cycles of follow-up were 1727 (64.5%). The median (interquartile range) of total male alcohol consumption was 4.5 (2.0-7.8) and 4.1 (1.0-8.6) standard servings per week in the SF and PRESTO cohorts, respectively. In pooled analyses, adjusted FRs for male alcohol consumption of 1-5, 6-13 and ≥14 standard servings per week compared with no alcohol consumption were 1.02 (95% CI: 0.90-1.17), 1.10 (95% CI: 0.96-1.27) and 0.98 (95% CI: 0.81-1.18), respectively. For SF, adjusted FRs of 1-5, 6-13 and ≥14 standard servings per week compared with no alcohol consumption were 0.97 (95% CI: 0.73-1.28), 0.81 (95% CI: 0.60-1.10) and 0.82 (95% CI: 0.51-1.30), respectively. For PRESTO, adjusted FRs of 1-5, 6-13 and ≥14 standard servings per week compared with no alcohol consumption were 1.02 (95% CI: 0.88-1.18), 1.20 (95% CI: 1.03-1.40) and 1.03 (95% CI: 0.84-1.26), respectively.

LIMITATIONS, REASONS FOR CAUTION

Male alcohol consumption was ascertained at baseline only, and we did not distinguish between regular and binge drinking. In addition, we had insufficient numbers to study the effects of specific types of alcoholic beverages. As always, residual confounding by unmeasured factors, such as dietary factors and mental health, cannot be ruled out. Comorbidities thought to play a role in the reproductive setting (i.e. cancer, metabolic syndrome) were not considered in this study; however, the prevalence of cancer and diabetes was low in this age group. Findings for the highest categories of alcohol consumption (6-13 and ≥14 servings/week) were not consistent across the two cohorts.

WIDER IMPLICATIONS OF THE FINDINGS

Despite little evidence of an association between male alcohol consumption and reduced fecundability in the pooled analysis, data from the Danish cohort might indicate a weak association between reduced fecundability and consumption of six or more servings per week.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Institutes of Health (R01-HD060680, R01-HD086742, R21-HD050264, R21-HD072326, R03-HD090315), the Novo Nordisk Foundation, Oticon Fonden, Politimester J.P.N. Colind og hustru Asmine Colinds mindelegat and Erna og Peter Houtveds studielegat. PRESTO receives in-kind donations from FertilityFriend.com, Kindara.com, Swiss Precision Diagnostics and Sandstone Diagnostics for the collection of data pertaining to fertility. Dr Wise serves as a consultant on uterine leiomyomata for AbbVie.com. All other authors declare no conflict of interest.

Psychological stress, stressful life events, male factor infertility, and testicular function: a cross-sectional study

OBJECTIVE

To assess the association between psychological stress and male factor infertility as well as testicular function (semen quality, serum reproductive hormones) and erectile dysfunction.

DESIGN

Cross-sectional study.

SETTING

University Hospital-based research center.

PATIENTS

Men with impaired semen quality were included from infertile couples, and men with naturally conceived pregnant partners were used as a reference population.

INTERVENTIONS

Participants completed a questionnaire on health and lifestyle, including a 14-item questionnaire about self-rated psychological stress symptoms and stressful life event (SLEs), had a physical examination performed, delivered a semen sample and had a blood sample drawn.

MAIN OUTCOMES

Differences in stress scores (calculated from self-reported stress symptoms) and SLEs between infertile and fertile men were assessed in crude and fully adjusted linear regression models. Secondary outcomes were semen quality, serum reproductive hormones, and erectile dysfunction.

RESULTS

Of 423 men, 176 (41.6%) experienced at least one SLE in the 3 months prior to inclusion (50.4%/36.9%: infertile/fertile men, P = .03); β-coefficient and 95% confidence interval for the difference between the groups on the transformed scale in fully adjusted linear regression models was 0.18 (0.06, 0.30). However, there were no differences in psychological stress symptoms between the two groups (β-coefficient and 95% confidence interval) on the transformed scale (0.14; -0.02, 0.30). No association between stress (self-reported stress symptoms and SLEs) and testicular function or with erectile dysfunction was found in any of the men.

CONCLUSION

Infertile men reported a higher number of SLEs than fertile men but did not report more psychological stress symptoms. Distress and SLEs were not associated with reduced male reproductive function.

Associations of Fish Oil Supplement Use With Testicular Function in Young Men

IMPORTANCE

Many young men have poor semen quality, and the causes are often unknown. Supplement intake of ω-3 polyunsaturated fatty acid has been found to improve semen quality among men with infertility, but the association with semen quality among healthy men is unknown.

OBJECTIVE

To determine if intake of ω-3 fatty acid supplements is associated with testicular function as measured by semen quality and reproductive hormone levels among healthy men.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included young Danish men from the general population recruited between January 1, 2012, and December 31, 2017, at compulsory examinations to determine their fitness for military service. Young unselected men were approached after the examination and invited to participate in a study of reproductive function, regardless of their fitness for military service. Data analysis was conducted from September 1, 2018, to June 30, 2019.

EXPOSURES

Intake of supplements, including fish oil, during the past 3 months.

MAIN OUTCOMES AND MEASURES

Semen quality, measured as volume, concentration, total sperm count, percentage of morphologically normal spermatozoa, and motility, and serum reproductive hormone levels, measured as follicle-stimulating hormone, luteinizing hormone, testosterone, free testosterone, and inhibin B levels.

RESULTS

Among 1679 young Danish men (median [interquartile range] age, 18.9 [18.7-19.4] years) recruited to participate, 98 men (5.8%) reported use of fish oil supplements during the past 3 months, of whom 53 (54.1%) reported intake on 60 or more days. After adjustment and compared with men with no supplement intake, men with fish oil supplement intake on fewer than 60 days had semen volume that was 0.38 (95% CI, -0.03 to 0.80) mL higher, and men with fish oil supplement intake on 60 or more days had semen volume that was 0.64 (95% CI, 0.15 to 1.12) mL higher (P for trend < .001). Similarly, testicular size in men with supplement intake on fewer than 60 days was 0.8 (95% CI, -0.2 to 1.9) mL larger and in men with fish oil supplement intake on 60 or more days was 1.5 (95% CI, 0.2 to 2.8) mL larger compared with men with no supplement intake (P for trend = .007). After adjustment, men with fish oil supplement intake had a 20% (95% CI, 9%-31%) lower follicle-stimulating hormone level and 16% (95% CI, 8%-24%) lower luteinizing hormone level compared with men with no supplement intake. There were no associations of intake of other supplements with measures of testicular function.

CONCLUSIONS AND RELEVANCE

These findings suggest that intake of fish oil supplements was associated with better testicular function, which is less likely to be due to confounding by indication, as no associations of intake of other supplements with testicular function were found. This cross-sectional study did not examine the actual content of ω-3 fatty acids in the supplements; therefore, these findings need confirmation in well-designed randomized clinical trials among unselected men.