Impact of male obesity on infertility: a critical review of the current literature

Influence of male body mass index on semen analysis parameters and in vitro fertilization outcomes

Concurrent global increase of prevalence of obesity and male fertility implies link between overweight and obesity with male subfertility. This hypothesis is supported by numerous population-based epidemiological studies. Increase in body mass index (BMI) is associated with poor sperm quality in fertile, and more noticeable in infertile men. Nevertheless, some studies disprove damaging effect of BMI on semen quality. To examine the influence of men's BMI in infertile couples undergoing in vitro fertilization (IVF) on semen analysis parameters and IVF outcomes. Study encompassed all couples who underwent IVF at Gynecology and Obstetrics Clinic Narodni Front in Belgrade during 2018 and 2019. Exclusion criteria were azoospermia, conditions and diseases that could affect the semen analysis parameters (diabetes, malignant diseases treated with radiation and/or chemotherapy, trauma or surgery of the genital organs, mumps or undescended testicles in childhood). Evaluated semen analysis parameters included semen ejaculate volume, sperm pH, sperm count, sperm motility, and sperm morphology. IVF outcomes comprised total number of embryos, number and percentage of obtained good-quality embryos and clinical pregnancy rates. Based on BMI value, participants were divided into a group of underweight (Group 1), normally weight (Group 2), overweight (Group 3), and obese men (Group 4). After applying inclusion and exclusion criteria, 411 men (couples) were included in the analysis. The largest number of men were overweight, while the smallest belonged to the group of underweight participants. There are no significant differences in the semen analysis parameters between study groups. Correlation analysis shown weak and insignificant correlation between BMI and semen analysis parameters. The number and proportion of good quality embryos is significantly lower in overweight and obese study groups compared to normal weight and underweight groups (2.89, 2.91, 2.42, and 2.36, respectively, P = .041). The differences in other IVF outcomes: total number of embryos (3.61, 3.74, 3.21, and 3.37, respectively) and clinical pregnancy rates (41.26%, 43.09%, 42.78%, and 39.95%, respectively) between study groups were not significant (P > .05). BMI does not significantly affect semen analysis parameters, but a higher BMI is associated with a lower number and proportion of good quality embryos in IVF outcomes.

Association between central obesity and semen quality: A cross-sectional study in 4513 Chinese sperm donation volunteers

BACKGROUND

General obesity classified by body mass index has been linked to a reduction in semen quality; however, evidence on the adverse effect of central obesity on semen quality remains limited.

OBJECTIVES

To investigate the association between central obesity and semen quality.

MATERIALS AND METHODS

We conducted a cross-sectional study of 4513 sperm donation volunteers in Guangdong Provincial Human Sperm Bank during 2018-2021. Three central obesity indicators, including waist circumference, waist-to-hip ratio, and waist-to-height ratio, were measured using a multi-frequency bioelectrical impedance analysis for each subject. Semen analysis was conducted according to the World Health Organization laboratory manual for the examination and processing of human semen 5th edition. Linear regression models and unconditional logistic regression models were used to quantify the association between central obesity and semen parameters.

RESULTS

With adjustment for age, race, education level, marital status, fertility status, occupation, year of semen collection, abstinence period, ambient temperature, and relative humidity, central obesity defined as waist circumference ≥90 cm, waist-to-hip ratio ≥0.9, or waist-to-height ratio ≥0.5 was significantly associated with a 0.27 (95% confidence interval: 0.15, 0.38) mL, 14.47 (3.60, 25.34) × 106 , 7.06 (0.46, 13.76) × 106 , and 6.80 (0.42, 13.18) × 106 reduction in semen volume, total sperm number, total motile sperm number, and total progressive motile sperm number, respectively, and a 53% (10%, 112%) increase in odds of below the World Health Organization 2010 reference value for semen volume. These associations did not significantly vary across age. Similar results were observed for central obesity defined using each of the three indicators, except that subjects with a waist circumference ≥90 cm had a slightly higher total motility (estimated change: 1.30%; 95% confidence interval: 0.27%, 2.34%) and progressive motility (estimated change: 1.27%; 95% confidence interval: 0.23%, 2.31%).

DISCUSSION AND CONCLUSION

We found that central obesity was significantly associated with a reduction in semen volume, total sperm number, total motile sperm number, and total progressive motile sperm number. Future studies are warranted to confirm our results in other regions and populations.

The Molecular Basis of Male Infertility in Obesity: A Literature Review

The rising incidence of obesity has coincided with rising levels of poor reproductive outcomes. The molecular basis for the association of infertility in obese males is now being explained through various mechanisms. Insulin resistance, hyperglycemia, and changes in serum and gonadal concentrations of adipokines, like leptin, adiponectin, resistin, and ghrelin have been implicated as causes of male infertility in obese males. The effects of obesity and hypogonadism form a vicious cycle whereby dysregulation of the hypothalamic-pituitary-testicular axis-due to the effect of the release of multiple mediators, thus decreasing GnRH release from the hypothalamus-causes decreases in LH and FSH levels. This leads to lower levels of testosterone, which further increases adiposity because of increased lipogenesis. Cytokines such as TNF-α and interleukins, sirtuins, and other inflammatory mediators like reactive oxygen species are known to affect fertility in obese male adults. There is evidence that parental obesity can be transferred through subsequent generations to offspring through epigenetic marks. Thus, negative expressions like obesity and infertility have been linked to epigenetic marks being altered in previous generations. The interesting aspect is that these epigenetic expressions can be reverted by removing the triggering factors. These positive modifications are also transmitted to subsequent generations.

Association between waist circumference and female infertility in the United States

BACKGROUND

Obesity has significant implications for fertility and reproductive health. However, evidences linking abdominal obesity to female infertility were limited and inconclusive. Our objective was to figure out the potential relationship between waist circumference (WC) and infertility among women of childbearing age in the United States using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

Our cross-sectional study included 3239 female participants aged 18-45 years. To explore the independent relationship between WC and female infertility, the weighted multivariable logistic regression and smoothed curve fitting were performed. Interaction and subgroup analyzes were then conducted for secondary analysis.

RESULTS

WC was positively associated with female infertility independent of BMI after adjusting for BMI and other potential confounders. In fully adjusted model, for every 1cm increase in waist circumference, the risk of infertility increased by 3% (OR = 1.03, 95% CI: 1.01-1.06). When WC was divided into five equal groups, women in the highest quintile had 2.64 times risk of infertility than that in the lowest quintile (OR = 2.64, 95% CI: 1.31-5.30). Smooth curve fitting revealed a non-linear but positively dose-dependent relationship between WC and female infertility. Furthermore, we found an inverted U-shaped relationship (turning point: 113.5 cm) between WC and female infertility in participants who had moderate recreational activities and a J-shaped relationship (turning point: 103 cm) between WC and female infertility in participants who had deficient recreational activities.

CONCLUSIONS

Waist circumference is a positive predictor of female infertility, independent of BMI. Moderate recreational activities can lower the risk of female infertility associated with abdominal obesity.

Effects of the low-carb organic Mediterranean diet on testosterone levels and sperm DNA fragmentation

The causes of male infertility can vary. Lifestyles, environmental factors, stressful conditions, and socio-economic conditions are significant factors. Diet plays a crucial role in improving a man's reproductive capacity. The appropriate diet should be diverse and ensure the intake of all the necessary nutrients to enhance sperm quality. The Mediterranean diet, which includes high amounts of vegetables and fruits rich in detoxifying and antioxidant substances, as well as polyphenols, flavonoids, carotenoids, and microelements, especially when consumed with organic foods and a lower carbohydrate regimen, are the key aspects addressed in this study. The objective of this research was to modify the diets of 50 subfertile men by providing them with a specific nutritional plan. This plan included consuming 80% organic foods, introducing whole grains and low glycemic load options, eliminating refined carbohydrates, consuming green leafy vegetables and red fruits daily, reducing or eliminating dairy products, consuming primarily grass-fed meat and wild caught seafood, eliminating saturated fats in favor of healthy fats like olive oil, avocado, and nuts. After three months of adhering to the low-carb food plan, testosterone levels significantly increased, while sperm DNA fragmentation decreased in a subgroup of individuals who reduced their carbohydrate intake by 35%.

Association between childhood obesity and infertility in later life: a systematic review of cohort studies

BACKGROUND

The global prevalence of childhood obesity has exhibited a troubling surge in recent years. Due to the raised questions regarding its potential correlation with infertility in adulthood, this systematic review has been undertaken to explore the relationships between childhood obesity, and infertility later in life.

METHODS

A comprehensive search was performed in three international databases (PubMed, Web of Science, and Scopus). All cohort (retrospective or prospective), case-cohort, and nested case-control studies until April 2022 which assessed the association of obesity in children and adolescents with male and female infertility indicators in later life were included. The quality of the included studies was assessed by Newcastle-Ottawa quality assessment checklists.

RESULT

Out of the initial 32,501 documents, eleven eligible studies with a total sample size of 498,980 participants were included. Five studies focused on the number of offspring and indicated that obesity, especially in adolescence had an association with later life lower number of children, nulliparity, and childlessness in both men and women. Concerning conceiving problems, two studies showed that obesity before age 12 increased the risk of female fertility problems in the future. Two studies reported that obesity in early life raised the risk of impaired female reproductive system such as menstrual or ovulatory problems. As well as females, a study discovered that obesity in men during their 20s was linked to an elevated risk of low sperm motility and poor sperm morphology. Another study has reported men with higher pre-pubertal BMI had lower sex hormone-binding globulin; however, the same association was not seen between childhood BMI and semen quality.

CONCLUSION

The evidence suggests a positive association between childhood obesity with infertility indicators in later life. Childhood weight reduction strategies are suggested to be implemented in societies in order to reduce infertility rates in later life.

Predictive factors for successful testicular biopsy

INTRODUCTION

Infertility, the inability to conceive, constitutes a major problem in modern societies. It affects 10 to 15 percent of couples in the United States. Evaluation of infertile men is usually complex and often demands a testicular biopsy.

MATERIALS AND METHODS

We reviewed all azoospermic men submitted to testicular biopsy, in our center, during infertility investigation between January 2015 and December 2021.

RESULTS

A total of 117 patients with a mean age of 36.5 was considered. Biopsy was positive, as defined by the presence of viable spermatozoids by microscopy, in 48.7% of patients (n = 57). Patients were divided in two separate groups based on positive (PB) or negative biopsy (NB) and compared. PB-group had normal serum total testosterone levels and higher than NB-group (3.7 ng/mL vs. 2.85 ng/mL, p = 0.021), and normal serum FSH levels and lower than NB-group (6.0 mIU/mL vs. 16.0 mIU/mL, p < 0.001). The groups were similar concerning serum LH levels (3.9 mIU/mL vs. 6.3 mIU/mL, p = 0.343.

CONCLUSIONS

Predicting outcomes of testicular biopsy is a difficult task. Our study found that men with normal testicular volume, normal levels of testosterone and FSH and those with type 1 diabetes mellitus had a higher probability of positive testicular biopsy.

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.

Extra-virgin olive oil ameliorates high-fat diet-induced seminal and testicular disorders by modulating the cholesterol pathway

BACKGROUND

Rabbits are sensitive to dietary cholesterol and rapidly develop hypercholesterolemia, leading to prominent subfertility. Sterol regulatory element-binding protein isoform 2 drives the intracellular cholesterol pathway in many tissues, including the testicles. Its abnormal regulation could be the mainly responsible for the failure of suppressing cholesterol synthesis in a cholesterol-enriched environment, ultimately leading to testicular and seminal alterations. However, extra-virgin olive oil consumption has beneficial properties that promote lowering of cholesterol levels, including the recovery of seminal parameters altered under a high-fat diet.

OBJECTIVES

Our goal was to investigate the effects of high-fat diet supplementation with extra-virgin olive oil at the molecular level on rabbit testes, by analyzing sterol regulatory element-binding protein isoform 2 protein and its corresponding downstream effectors.

MATERIALS AND METHODS

During 12 months, male rabbits were fed a control diet, high-fat diet, or 6-month high-fat diet followed by 6-month high-fat diet plus extra-virgin olive oil. Serum lipids, testosterone levels, bodyweight, and seminal parameters were tested. The mRNA and protein levels of sterol regulatory element-binding protein isoform 2, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, and low-density lipoprotein receptor were determined by semi-quantitative polymerase chain reaction and Western blotting techniques. The expression pattern of sterol regulatory element-binding protein isoform 2 protein in the rabbit testicles was studied by indirect immunofluorescence. In addition, testicular cholesterol was detected and quantified by filipin staining and gas chromatography.

RESULTS

The data showed that the addition of extra-virgin olive oil to high-fat diet reduced testicular cholesterol levels and recovered the expression of sterol regulatory element-binding protein isoform 2, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, and low-density lipoprotein receptor initially altered by the high-fat diet.

DISCUSSION AND CONCLUSIONS

The combination of high-fat diet with extra-virgin olive oil encourages testicular recovery by modifying the expression of the enzymes related to intracellular cholesterol management.

Maternal Prepregnancy Obesity Affects Foetal Growth, Birth Outcome, Mode of Delivery, and Miscarriage Rate in Austrian Women

The increasing obesity rates among women of reproductive age create a major obstetrical problem as obesity during pregnancy is associated with many complications, such as a higher rate of caesarean sections. This medical record-based study investigates the effects of maternal prepregnancy obesity on newborn parameters, birth mode, and miscarriage rate. The data of 15,404 singleton births that had taken place between 2009 and 2019 at the public Danube Hospital in Vienna were enrolled in the study. Newborn parameters are birth weight, birth length, head circumference, APGAR scores, as well as pH values of the arterial and venous umbilical cord blood. In addition, maternal age, height, body weight at the beginning and the end of pregnancy, and prepregnancy body mass index (BMI) (kg/m²) have been documented. The gestational week of birth, the mode of delivery, as well as the number of previous pregnancies and births, are included in the analyses. Birth length, birth weight, and head circumference of the newborn increase with increasing maternal BMI. Furthermore, with increasing maternal weight class, there tends to be a decrease in the pH value of the umbilical cord blood. Additionally, obese women have a history of more miscarriages, a higher rate of preterm birth, and a higher rate of emergency caesarean section than their normal-weight counterparts. Consequently, maternal obesity before and during pregnancy has far-reaching consequences for the mother, the child, and thus for the health care system.

Integrated Computational Approaches for Inhibiting Sex Hormone-Binding Globulin in Male Infertility by Screening Potent Phytochemicals

Male infertility is significantly influenced by the plasma-protein sex hormone-binding globulin (SHBG). Male infertility, erectile dysfunction, prostate cancer, and several other male reproductive system diseases are all caused by reduced testosterone bioavailability due to its binding to SHBG. In this study, we have identified 345 phytochemicals from 200 literature reviews that potentially inhibit severe acute respiratory syndrome coronavirus 2. Only a few studies have been done using the SARS-CoV-2 inhibitors to identify the SHBG inhibitor, which is thought to be the main protein responsible for male infertility. In virtual-screening and molecular-docking experiments, cryptomisrine, dorsilurin E, and isoiguesterin were identified as potential SHBG inhibitors with binding affinities of -9.2, -9.0, and -8.8 kcal/mol, respectively. They were also found to have higher binding affinities than the control drug anastrozole (-7.0 kcal/mol). In addition to favorable pharmacological properties, these top three phytochemicals showed no adverse effects in pharmacokinetic evaluations. Several molecular dynamics simulation profiles' root-mean-square deviation, radius of gyration, root-mean-square fluctuation, hydrogen bonds, and solvent-accessible surface area supported the top three protein-ligand complexes' better firmness and stability than the control drug throughout the 100 ns simulation period. These combinatorial drug-design approaches indicate that these three phytochemicals could be developed as potential drugs to treat male infertility.

Spermatogenesis and steroidogenesis disruption in a model of metabolic syndrome rats

CONTEXT

Metabolic syndrome (MetS) is a clustering of several physiological alterations.

OBJECTIVE

This study was designed to evaluate the effects of MetS on rats spermatogenesis and steroidogenesis.

MATERIALS AND METHODS

We developed a MetS rodent model using high-sugar and high-fat diet.

RESULTS

MetS rats showed severe disorders in sperm parameters. Interestingly, a significant increase in malondialdehyde level and a decrease in the antioxidant activities were observed. Moreover, qRT-PCR analysis showed Bax down-regulation and Bcl-2 up-regulation. A decrease in testosterone level was identified, correlated with the CYP11A1, CYP17A1 and 17β HSD testicular marker down-regulation. Finally, MetS rats showed an up-regulation of pro-inflammatory cytokines receptors IL-1R and IL-6R.

CONCLUSION

MetS induced severe testis toxicity in male rats. Mets markedly distorted sperm parameters, inhibited the transcription of steroidogenic enzymes and led to oxidative stress, inflammation, and alteration of Bax/Bcl-2 ratioin testicular tissues.

Effects of Chokeberries (Aronia spp.) on Cytoprotective and Cardiometabolic Markers and Semen Quality in 109 Mildly Hypercholesterolemic Danish Men: A Prospective, Double-Blinded, Randomized, Crossover Trial

Background: Chokeberries (Aronia spp.) are known to exhibit both direct and indirect antioxidant properties and have been associated with beneficial effects on human health, including cardiovascular risk factors (inflammation, serum lipids, sugars, blood pressure), oxidative stress, and semen quality. This prospective, double-blinded, randomized, crossover clinical trial was conducted to elucidate the effects of Aronia supplementation on these health targets in mildly hypercholesterolemic men. Methods: The standardized Aronia supplementation comprised three wild Aronia spp. (A. arbutifolia, A prunifolia and A. melanocarpa) and the Aronia hybrid × Sorbaronia mitschurinii (standardized to 150 mg anthocyanins daily). Participants (n = 109) were healthy men with respect to all outcome targets except for the total cholesterol level (5.0−7.0 mM). Participants were randomized to supplementation with either Aronia or placebo for 90 days, followed by a wash-out period and lastly the complementary supplementation. Effects on the health parameters were compared among both the whole group of men and in subgroups according to age, body mass index (BMI), lifestyle, dietary habits, and serum glutathione levels at baseline. The study is registered in ClinicalTrials.gov.: NCT03405753. Results: Glutathione levels were significantly improved after 90 days intake of Aronia supplementation compared to placebo in the subgroup of men with a low level of glutathione at baseline (p = 0.038) and a high coffee intake (p = 0.045). A significant decrease in levels of sperm DNA fragmentation and an increase in the percentage of motile sperm were observed in men aged >40 and in men with BMI > 25. Further, these parameters were significantly improved in the dietary subgroup defined by a high level of coffee intake. Total cholesterol and low-density lipoprotein-cholesterol levels decreased significantly in men <40 years after Aronia supplementation. No statistically significant effects were observed regarding blood pressure, markers of blood sugar regulation, hemoglobin A1c, superoxide dismutase, catalase, isoprostane levels, high sensitivity C reactive protein, or other semen parameters. Conclusions: This study demonstrated a significant increase in glutathione levels and improvement of cytoprotective targets following Aronia supplementation in specific subgroups of men >40 years of age and BMI > 25 but did not demonstrate a significant effect in the overall analysis. The observed concurrent increase in glutathione levels and improvement of cytoprotective targets following Aronia supplementation in subgroups of men, suggests that the endogenous phase II antioxidant glutathione is involved in the modulation of the observed cytoprotective effects. This study is a good foundation for further investigation of these cytoprotective effects in groups with oxidative stress in a dose−response study.

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

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

Effects of dietary supplementation of different oils and conjugated linoleic acid on the reproductive and metabolic aspects of male mice

The present study was carried out to examine first, if diets enriched with 320 g of the base diet with common dietary oils including fish oil, olive oil, hydrogenated sunflower seed (H-SFS) oil, flaxseed oil and sunflower seed oil (SFS) could induce weight gain and alter reproductive and metabolic characteristics of male mice. Second, whether the addition of conjugated linoleic acid (CLA, 10% of the diet) could ameliorate any negative effects. In this cross-sectional study, 90 four-week-old male NMRI mice were used in two consecutive experiments. A high level of dietary oils negatively affected some reproductive and metabolic characteristics of male mice (p < 0.05), specifically, sunflower seed oil enrichment resulted in higher HDL levels and apoptosis of germinal epithelial cells. An olive oil-enriched diet caused an increase in plasma triglyceride concentrations and germinal cell apoptosis, as well as a decrease in sperm concentration and perturbed spermatogenesis. When CLA was fed in conjunction with dietary oils it successfully mitigated some of the negative reproductive and metabolic characteristics. We conclude that male reproductive processes are affected by high dietary oils, even before signs of obesity are evident. Inclusion of dietary CLA may provide some benefit to offset negative effects, although further studies are required.

Effects of Moderate-Intensity Continuous Training and High-Intensity Interval Training on Testicular Oxidative Stress, Apoptosis and m6A Methylation in Obese Male Mice

Exercise is an effective way to improve reproductive function in obese males. Oxidative stress and apoptosis are important pathological factors of obesity-related male infertility. Accumulating studies have demonstrated that N6-methyladenosine (m6A) methylation is associated with obesity and testicular reproductive function. Our study aimed to investigate and compare the effect of 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on testicular oxidative stress, apoptosis and m6A methylation in obese male mice. Male C57BL/6 mice were randomly allocated into the four groups: normal diet (ND) group, high-fat diet (HFD) group, high-fat diet with moderate-intensity continuous training (HFD-MICT) group and high-fat diet with high-intensity interval training (HFD-HIIT) group. Mice in the HFD-MICT and HFD-HIIT groups were subjected to 8 weeks of MICT or HIIT treadmill protocols after 12 weeks of HFD feeding. We found that MICT and HIIT increased the protein expression of Nrf2, HO-1 and NQO-1 in the testes of obese mice, and HIIT increased it more than MICT. The Bax/Bcl-2 ratio, Cleaved Caspase-3 protein expression and TUNEL-positive cells were consistently up-regulated in the testes of obese mice, but MICT and HIIT restrained these HFD-induced effects. In addition, HFDs increased m6A levels and the gene expression of METTL3, YTHDF2 and FTO in the testes, but these effects were reversed by MICT and HIIT. However, HIIT was more effective than MICT in reducing m6A methylation in the testes of obese mice. These results demonstrate that both MICT and HIIT protected against HFD-induced oxidative stress, apoptosis and m6A methylation in testicular tissues; as a result, testicular morphological and functional impairment improved. In particular, HIIT was more beneficial than MICT in increasing the mRNA expression of steroidogenic enzymes and testicular antioxidant capacity and decreasing m6A methylation in the testes of HFD-fed mice.

High-fat diet during sexual maturation induces hyperplastic differentiation of rat prostate and higher expression of AR45 isoform and ERα

We examined the consequences of high-fat diet (HFD) on prostate histophysiology in two periods along sexual maturation of rats and the impact on the gland in adulthood. After weaning, male Wistar rats were fed a balanced diet (4 % fat-C3, C6, C9) or a HFD (20 % fat- HF3, HF6, HF9) for 3, 6 or 9 weeks. Fat deposit weights, blood glucose and levels of serum testosterone and estrogen were measured. Prostate was evaluated for histology, proliferative and apoptotic cell index, and for the expression of androgen (AR), estrogen receptors type α (ERα) and aromatase. HFD did not affect estrogen levels and elevated serum testosterone only in HF9. HFD reduced prostate weight in HF6 and increased it in adulthood (HF9) but relative prostate weight was unchanged among groups. Cell proliferation, height and density were higher in epithelium of all HFD-groups, compared to controls, featuring the epithelial hyperplasia. Epithelial apoptosis was lower in HF9. HF3 and HF9 exhibited higher expressions of ERα, indicating that HFD triggers a new activation of ERα expression in the acinar epithelium. The content of prostatic aromatase was also elevated in HF9. Increased numbers of AR-positive cells were observed in all HFD groups, and western blotting analysis showed an increase in the truncated form of 45 kDa (AR45) and a reduction in the expression of 110 kDa-AR for HF3 and HF9. In conclusion, excessive dietary fats during sexual maturation of rats led to developmental programming of the prostate, inducing a hyperplastic status with perturbations in AR isoforms expression and reactivation of ERα in adulthood, whose implications for posterior prostatic health could be detrimental.

The effects and molecular mechanism of heat stress on spermatogenesis and the mitigation measures

Under normal conditions, to achieve optimal spermatogenesis, the temperature of the testes should be 2-6 °C lower than body temperature. Cryptorchidism is one of the common pathogenic factors of male infertility. The increase of testicular temperature in male cryptorchidism patients leads to the disorder of body regulation and balance, induces the oxidative stress response of germ cells, destroys the integrity of sperm DNA, yields morphologically abnormal sperm, and leads to excessive apoptosis of germ cells. These physiological changes in the body can reduce sperm fertility and lead to male infertility. This paper describes the factors causing testicular heat stress, including lifestyle and behavioral factors, occupational and environmental factors (external factors), and clinical factors caused by pathological conditions (internal factors). Studies have shown that wearing tight pants or an inappropriate posture when sitting for a long time in daily life, and an increase in ambient temperature caused by different seasons or in different areas, can cause an increase in testicular temperature, induces testicular oxidative stress response, and reduce male fertility. The occurrence of cryptorchidism causes pathological changes within the testis and sperm, such as increased germ cell apoptosis, DNA damage in sperm cells, changes in gene expression, increase in chromosome aneuploidy, and changes in Na⁺/K⁺-ATPase activity, etc. At the end of the article, we list some substances that can relieve oxidative stress in tissues, such as trigonelline, melatonin, R. apetalus, and angelica powder. These substances can protect testicular tissue and relieve the damage caused by excessive oxidative stress.

The Impact of Bariatric Surgery on Assisted Reproductive Technology Outcomes: A Systematic Review

OBJECTIVE

There is a paucity of literature on the impact of bariatric surgery on artificial reproductive technology (ART) outcomes. This topic should be examined, given that most bariatric surgery candidates are of reproductive age and those with obesity are significantly more likely to experience poor fertility outcomes. This systematic review aimed to determine if bariatric surgery impacts ART outcomes and if effects vary between females and males.

DATA SOURCES

MEDLINE, EMBASE, SCOPUS, and the Cochrane Central Register of Controlled Trials were searched for English studies published between January 1978 and May 2021.

STUDY SELECTION

Studies with participants who had had bariatric surgery and subsequently underwent ART (i.e., in vitro fertilization or intracytoplasmic sperm injection) were eligible for inclusion. Screening, data abstraction, and risk of bias assessment were conducted independently and in duplicate.

DATA EXTRACTION AND SYNTHESIS

Of the 279 articles screened for eligibility, 25 were sought for full text review, and 7 were included for analysis. Four studies (57%) examined ART interventions in females, while 3 (43%) examined interventions in males. Data on cumulative live birth rate (CLBR) was extracted for all 7 studies (N = 169). There were 50 live births with CLBRs ranging from 0.0% to 80.0%. Changes to female secondary outcomes were varied. Data on male secondary outcomes were contradictory: 1 study indicated improved sperm parameters following bariatric surgery, while 2 showed decreased parameters, with certain participants seeing improvements after several months.

CONCLUSION

Bariatric surgery prior to ART may have an impact on CLBRs; however, high-quality research is needed to delineate the direct effects of bariatric surgery on ART outcomes. Various sex-specific outcomes should be considered prior to recommending ART after bariatric surgery. Future research should determine the optimal type of bariatric surgery and timing of ART following bariatric surgery.

Bariatric Surgery and Osteoporosis

It has been increasingly acknowledged that bariatric surgery adversely affects skeletal health. After bariatric surgery, the extent of high-turnover bone loss is much greater than what would be expected in the absence of a severe skeletal insult. Patients also experience a significant deterioration in bone microarchitecture and strength. There is now a growing body of evidence that suggests an association between bariatric surgery and higher fracture risk. Although the mechanisms underlying the high-turnover bone loss and increase in fracture risk after bariatric surgery are not fully understood, many factors seem to be involved. The usual suspects are nutritional factors and mechanical unloading, and the roles of gut hormones, adipokines, and bone marrow adiposity should be investigated further. Roux-en-Y gastric bypass (RYGB) was once the most commonly performed bariatric procedure worldwide, but sleeve gastrectomy (SG) has now become the predominant bariatric procedure. Accumulating evidence suggests that RYGB is associated with a greater reduction in BMD, a greater increase in markers of bone turnover, and a higher risk of fracture than SG. These findings should be taken into consideration in determining the most appropriate bariatric procedure for patients, especially those at higher fracture risk. Before and after all bariatric procedures, sufficient calcium, vitamin D and protein intake, and adequate physical activity, are needed to counteract negative impacts on bone. There are no studies to date that have evaluated the effect of osteoporosis treatment on high-turnover bone loss after bariatric surgery. However, in patients with a diagnosis of osteoporosis, anti-resorptive agents may be considered.

Obesity and male infertility: multifaceted reproductive disruption

Background

The global prevalence of obesity has soared to a concerning height in the past few decades. Interestingly, the global decline in semen quality is a parallel occurrence that urges researchers to evaluate if obesity is among the most essential causatives of male infertility or subfertility.

Main body

Obesity may alter the synchronized working of the reproductive-endocrine milieu, mainly the hypothalamic-pituitary-gonadal (HPG) axis along with its crosstalks with other reproductive hormones. Obesity-mediated impairment in semen parameters may include several intermediate factors, which include physical factors, essentially increased scrotal temperature due to heavy adipose tissue deposits, and systemic inflammation and oxidative stress (OS) initiated by various adipose tissue-derived pro-inflammatory mediators. Obesity, via its multifaceted mechanisms, may modulate sperm genetic and epigenetic conformation, which severely disrupt sperm functions. Paternal obesity reportedly has significant adverse effects upon the outcome of assisted reproductive techniques (ARTs) and the overall health of offspring. Given the complexity of the underlying mechanisms and rapid emergence of new evidence-based hypotheses, the concept of obesity-mediated male infertility needs timely updates and pristine understanding.

Conclusions

The present review comprehensively explains the possible obesity-mediated mechanisms, especially via physical factors, OS induction, endocrine modulation, immune alterations, and genetic and epigenetic changes, which may culminate in perturbed spermatogenesis, disrupted sperm DNA integrity, compromised sperm functions, and diminished semen quality, leading to impaired male reproductive functions.

Bariatric Surgery Does Not Improve Semen Quality: Evidence from a Meta-analysis

The meta-analysis aimed to explore the possible relationship between bariatric surgery and semen quality. PubMed, EMBASE, and CENTRAL were searched from database inception through October 28, 2021. Articles were eligible for inclusion if they evaluated the impact pre- and post-bariatric surgery on semen parameters. A total of 9 studies with 218 patients were found. The mean preoperative age distribution of the patients included centralized from 18 to 50 years, and the mean pre-op BMI ranged from 36.7 to 70.5 kg/m². The follow-up period ranged from 6 to 24 months. The results revealed that bariatric surgery had no significant effect on sperm volume, concentration, total count, morphology, total motility, progressive motility, viability, semen pH, and semen leukocytes. Bariatric surgery does not improve semen quality in obese males.

High fat diet-induced obesity prolongs critical stages of the spermatogenic cycle in a Ldlr-/-.Leiden mouse model

Obesity can disturb spermatogenesis and subsequently affect male fertility and reproduction. In our study, we aim to elucidate at which cellular level of adult spermatogenesis the detrimental effects of obesity manifest. We induced high fat diet (HFD) obesity in low-density lipoprotein receptor knock-out Leiden (Ldlr^−/−.Leiden) mice, and studied the morphological structure of the testes and histologically examined the proportion of Sertoli cells, spermatocytes and spermatids in the seminiferous tubules. We examined sperm DNA damage and chromatin condensation and measured plasma levels of leptin, testosterone, cholesterol and triglycerides. HFD-induced obesity caused high plasma leptin and abnormal testosterone levels and induced an aberrant intra-tubular organisation (ITO) which is associated with an altered spermatids/spermatocytes ratio (2:1 instead of 3:1). Mice fed a HFD had a higher level of tubules in stages VII + VIII in the spermatogenic cycle. The stages VII + VII indicate crucial processes in spermatogenic development like initiation of meiosis, initiation of spermatid elongation, and release of fully matured spermatids. In conclusion, HFD-induced obese Ldlr^−/−.Leiden mice develop an aberrant ITO and alterations in the spermatogenic cycle in crucial stages (stages VII and VII). Thereby, our findings stress the importance of lifestyle guidelines in infertility treatments.

The impact of bariatric surgery on assisted reproductive technology outcomes: a systematic review protocol

BACKGROUND

Individuals with obesity are at higher risk of experiencing complications during their pregnancy and may also experience infertility, requiring assisted reproductive technologies (ART) to conceive. The current body of literature demonstrates that bariatric surgery decreases an individual's risk of developing a variety of obesity-related obstetrical conditions during and after pregnancy. However, the effects of bariatric surgery on ART outcomes are not well understood. Therefore, the paucity in the literature warrants a need to determine these effects.

METHODS

We will search electronic databases, including MEDLINE, Embase, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL), as well as the gray literature and the reference lists of included articles. We will screen all studies published between January 1978 and the present day that explore the impact of bariatric surgery on ART outcomes for women and men. We will include observational studies. Two independent reviewers will assess the studies for inclusion and extract data for each article. The main outcome that will be analyzed is live birth rate. Secondary outcomes such as time to conception, number of rounds of ART, type of bariatric surgery, and length of time between bariatric surgery and initiation of ART will also be recorded. Risk of bias will be conducted using the National Institutes of Health Study Quality Assessment Tools. A random effects model will be used to account for statistical analysis and results will be pooled with forest plots. In the event of statistical and reporting heterogeneity, we will provide a qualitative synthesis and narrative review of the results.

DISCUSSION

This review will provide information on the outcomes of ART following bariatric surgery and may help healthcare professionals make informed decisions about the length of time between bariatric surgery and initiation of ART. The study findings may be of interest to various stakeholders including patients, bariatric surgeons, obstetricians, and gynecologists, and those who specialize in obesity medicine and reproductive endocrinology and infertility. We plan to disseminate our findings through presentations, publications, and social media releases to individuals who are navigating infertility and are interested in undergoing or have undergone bariatric surgery, healthcare professionals, policymakers, and researchers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021252561.

Neonatal metformin short exposure inhibits male reproductive dysfunction caused by a high-fat diet in adult rats

Metformin (Met) is widely used to control blood glucose levels and acts on various organs, including reproductive tissues, to improve reproductive and lifespan. This study evaluated whether neonatal Met exposure prevented male reproductive dysfunction caused by being overweight during adulthood. Randomized Wistar rat pups received an intraperitoneal injection from postnatal days (PNDs) 1 to 12of saline (Sal; 0.9% NaCl/day in 2mL/kg) or Met (100 mg/kg/day in 2 mL/kg). From PNDs 60 to 90, the animals received a regular (R; 4.5% fat; Sal R and Met R groups) or a high-fat (HF; 35% fat; Sal HF and Met HF groups) diet. At PND 90, all animals were euthanized to evaluate their biometric and reproductive parameters. The Sal and Met groups with R showed similar body weights, however, the HF diet increased the body weight in both groups. The Sal HF group showed testicular damage regarding in antioxidant status and inflammatory profile in the epididymal cauda. The HF diet reduced Leydig and Sertoli cells numbers, with lower sperm quality. The Met R animals showed positive reproductive programming, due to improved antioxidant defense, inflammatory biomarkers, and sperm morphology. Met HF prevented HF diet damage to reproductive organs and sperm morphology, but not to sperm motility. Early Met exposure positively affected the male reproductive system of adult rats, preventing reproductive HF disorders. STATEMENT OF NOVELTY AND SIGNIFICANCE: Metformin is used to control type 2 diabetes mellitus and can act to improve metabolism and lifespan. Metformin avoidance is recommended during pregnancy, but there is no information regarding its use when breastfeeding. For the first time, we showed in this current study that metformin positively acts in the male reproductive tissues and helps involved in later life. These data showed a better antioxidant defense and anti-inflammatory profile of Metformin animals than Saline animals and might directly improve reproductive organs morphophysiology and sperm morphology. Also, the neonatal Met application programs the male reproduction to counterbalance damages from an obesogenic environment in later life.

Oxidative Stress, Testicular Inflammatory Pathways, and Male Reproduction

Inflammation is among the core causatives of male infertility. Despite male infertility being a serious global issue, "bits and pieces" of its complex etiopathology still remain missing. During inflammation, levels of proinflammatory mediators in the male reproductive tract are greater than usual. According to epidemiological research, in numerous cases of male infertility, patients suffer from acute or chronic inflammation of the genitourinary tract which typically occurs without symptoms. Inflammatory responses in the male genital system are inextricably linked to oxidative stress (OS). OS is detrimental to male fertility parameters as it causes oxidative damage to reproductive cells and intracellular components. Multifarious male infertility causative factors pave the way for impairing male reproductive functions via the common mechanisms of OS and inflammation, both of which are interlinked pathophysiological processes, and the occurrence of any one of them induces the other. Both processes may be simultaneously found in the pathogenesis of male infertility. Thus, the present article aims to explain the role of inflammation and OS in male infertility in detail, as well as to show the mechanistic pathways that link causative factors of male reproductive tract inflammation, OS induction, and oxidant-sensitive cellular cascades leading to male infertility.

Effect of diet-induced obesity on kisspeptin-neurokinin B-dynorphin A neurons in the arcuate nucleus and luteinizing hormone secretion in sex hormone-primed male and female rats

Metabolic stress resulting from either lack or excess of nutrients often causes infertility in both sexes. Kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the arcuate nucleus (ARC) has been suggested to be a key players in reproduction via direct stimulation of the pulsatile gonadotropin-releasing hormone (GnRH) and subsequent gonadotropin release in mammalian species. In this study, we investigated the effect of high-fat diet (HFD) on hypothalamic KNDy gene expression to examine the pathogenic mechanism underlying obesity-induced infertility in male and female rats. Male and female rats at 7 weeks of age were fed with either a standard or HFD for 4 months. In the male rats, the HFD caused a significant suppression of ARC Kiss1 and Pdyn gene expressions, but did not affect the plasma luteinizing hormone (LH) levels and sizes of the morphology of the testis and epididymis. In the female rats, 58% of the HFD-fed female rats exhibited irregular estrous cycles, whereas the remaining rats showed regular cycles. Two of the 10 rats that showed HFD-induced irregular estrous cycles showed profound suppression of LH pulse frequency and the number of ARC Kiss1-expressing cells, whereas the other females showed normal LH pulses and ARC Kiss1 expression. Our finding shows that suppression of ARC Kiss1 expression might be the initial pathological change of hypogonadotropic hypogonadism in HFD-fed male rats, while the obese-related infertility in the female rats may be mainly induced by KNDy-independent pathways. Taken together, ARC kisspeptin neurons in male rats may be susceptible to HFD-induced obesity compared with those in female rats.

Moringa oleifera ethanolic extract ameliorates the testicular dysfunction resulted from HFD-induced obesity rat model

In this study, we estimated the protective role of Moringa oleifera leaf ethanolic extract (MOLE) against obesity-associated testicular dysfunction. Fifty male albino rats were randomly assigned to five groups (n = 10): Group I (basal diet), group II (basal diet plus MOLE orally), group III (high-fat diet-HFD), group IV (HFD plus oral MOLE) and group V (HFD for 8 weeks followed by a basal diet plus oral MOLE for 6 weeks). The study duration extended for 14 weeks. Serum collected to investigate testosterone, FSH and LH levels. Testicular tissues were used to determine levels of SOD, glutathione, catalase and malondialdehyde. Semen was collected to estimate its quality (morphology, motility and concentration). Morphological changes in the testis were investigated by histopathological and immunohistochemical techniques. Compared with both control treatment and MOLE treatment, serum testosterone, FSH, LH, testicular enzymatic catalase, SOD, GSH, survivin immunoreactivity, sperm quality and testicular weight were all significantly decreased in rats treated with HFD, while there were significant increases in testicular malondialdehyde and caspase-3 immunoreactivity. MOLE improved all harmful effects of HFD. Improvements were more pronounced in the protected (G 4) than the treated (G 5) group. MOLE could be a potential solution for obesity-associated fertility problem.

Impact of high fat diet on the sterol regulatory element-binding protein 2 cholesterol pathway in the testicle

Male fertility has been shown to be dependent on cholesterol homeostasis. This lipid is essential for testosterone synthesis and spermatogenesis, but its levels must be maintained in an optimal range for proper testicular function. In particular, sperm cells' development is very sensitive to high cholesterol levels, noticeably during acrosomal formation. The aim of this work was to study whether the molecular pathway that regulates intracellular cholesterol, the sterol regulatory element-binding protein (SREBP) pathway, is affected in the testicles of animals under a fat diet. To investigate this, we took advantage of the non-obese hypercholesterolemia (HC) model in New Zealand rabbits that displays poor sperm and seminal quality. The testicular expression of SREBP isoform 2 (SREBP2) and its target molecules 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) and low-density lipoprotein receptor (LDLR) were studied under acute (6 months) and chronic (more than 12 months) fat intake by RT-PCR, western blot and immunofluorescence. Our findings showed that fat consumption promoted down-regulation of the SREBP2 pathway in the testicle at 6 months, but upregulation after a chronic period. This was consistent with load of testicular cholesterol, assessed by filipin staining. In conclusion, the intracellular pathway that regulates cholesterol levels in the testicle is sensitive to dietary fats, and behaves differently depending on the duration of consumption: it has a short-term protective effect, but became deregulated in the long term, ultimately leading to a detrimental situation. These results will contribute to the understanding of the basic mechanisms of the effect of fat consumption in humans with idiopathic infertility.

Analysis of the Functional Aspects of Sperm and Testicular Oxidative Stress in Individuals Undergoing Metabolic Surgery

PURPOSE

Metabolic surgery is a recommended treatment for obese patients that results in BMI reduction; however, the observed impact of this therapy on male fertility is inconsistent. This research aimed to study the effects of BMI changes after metabolic surgery on seminal analysis, sex hormonal profile, sperm functional integrity, and the seminal plasma lipid peroxidation levels.

MATERIALS AND METHODS

A prospective study was performed in 15 patients for whom metabolic surgery was recommended. The patients were evaluated by the techniques proposed in this study before and after the surgical procedure for 12 months. In each analysis, the male sex hormonal profile, semen analysis, sperm functional integrity, and seminal lipid peroxidation levels were assessed.

RESULTS

The surgery resulted in BMI reduction and improvement in seminal characteristics and male sex hormone profile. The semen analysis showed increases in volume, sperm progressive motility, and in sperm morphology and a decrease in immotile sperms. Sperm mitochondrial activity and sperm DNA integrity were improved, and the levels of seminal lipid peroxidation were decreased. The hormonal profile showed lower levels of estradiol and highest levels of luteinizing hormone (LH), sex hormone-binding globulin (SHBG), and testosterone.

CONCLUSION

BMI changes resulting from this treatment and its metabolic consequences can be associated with changes in the male fertile potential, leading to an improvement in the seminal quality, male sex hormone profile, sperm functional aspects, and levels of seminal lipid peroxidation, thus decreasing the testicular oxidative stress.

Efficacy of anastrozole in the treatment of hypogonadal, subfertile men with body mass index ≥25 kg/m2

Background

Anastrozole is a non-steroidal fourth generation aromatase inhibitor that stops the conversion of testosterone to estradiol and has been used as empiric medical therapy for the treatment of male infertility in men with an abnormal testosterone-to-estradiol ratio <10 in order to increase endogenous testosterone levels. This study sought to evaluate the efficacy of anastrozole in the treatment of hypogonadal, subfertile men with body mass index greater than 25 mg/kg² with respect to hormonal profile, semen parameters and overall fertility status.

Methods

Retrospective chart review was performed of hypogonadal, subfertile men with body mass index ≥25 kg/m² who were treated with anastrozole (1 mg daily). Hormonal measurements and semen analysis prior to and after treatment was analyzed in 30 men. Total motile count was calculated from semen analysis. Clinical pregnancy rates were recorded.

Results

Men treated with anastrozole had increases in follicle stimulating hormone (4.8 versus 7.6 IU/L, P<0.0001), luteinizing hormone (3.4 versus 5.4 IU/L, P<0.0001), testosterone (270.6 versus 412 ng/dL, P<0.0001) and testosterone-to-estradiol ratio (9 versus 26.5, P<0.0001) and decrease in estradiol level (32 versus 15.9 pg/mL, P<0.01) after 5 months of therapy. Increases in sperm concentration (7.8 versus 14.2 million/mL, P<0.001), total motile count (12.6 versus 17.7 million, P<0.01) and strict morphology (3.0% versus 3.5%, P<0.05) was appreciated. Clinical pregnancy rate for our cohort was 46.6% (14 of 30), with 71.4% (10 of 14) conceiving through in vitro fertilization, 14.2% (2 of 14) through intrauterine insemination and 14.2% (2 of 14) through natural intercourse.

Conclusions

Anastrozole improves hormonal profiles and semen parameters in hypogonadal, subfertile men with body mass index over 25 kg/m² and may aid in achieving pregnancy especially in conjunction with assisted reproductive techniques.

Neurotensin and Xenin Show Positive Correlations With Perceived Stress, Anxiety, Depressiveness and Eating Disorder Symptoms in Female Obese Patients

Objective

Neurotensin and xenin are two closely related anorexigenic neuropeptides synthesized in the small intestine that exert diverse peripheral and central functions. Both act via the neurotensin-1-receptor. In animal models of obesity reduced central concentrations of these peptides have been found. Dysregulations of the acute and chronic stress response are associated with development and maintenance of obesity. Until now, associations of both peptides with stress, anxiety, depressiveness, and eating disorder symptoms have not been investigated. The aim of the present study was to examine associations of neurotensin and xenin with these psychological characteristics under conditions of obesity.

Materials and Methods

From 2010 to 2016 we consecutively enrolled 160 inpatients (63 men and 97 women), admitted due to obesity and its mental and somatic comorbidities. Blood withdrawal und psychometric tests (PSQ-20, GAD-7, PHQ-9, and EDI-2) occurred within one week after admission. We measured levels of neurotensin and xenin in plasma by ELISA.

Results

Mean body mass index was 47.2 ± 9.5 kg/m². Concentrations of neurotensin and xenin positively correlated with each other (women: r = 0.788, p < 0.001; men: r = 0.731, p < 0.001) and did not significantly differ between sexes (p > 0.05). Women generally displayed higher psychometric values than men (PSQ-20: 58.2 ± 21.7 vs. 47.0 ± 20.8, p = 0.002; GAD-7: 9.7 ± 5.8 vs. 7.1 ± 5.3, p = 0.004; PHQ-9: 11.6 ± 6.6 vs. 8.8 ± 5.9, p = 0.008; EDI-2: 50.5 ± 12.8 vs. 39.7 ± 11.9, p < 0.001). Only women showed positive correlations of both neuropeptides with stress (neurotensin: r = 0.231, p = 0.023; xenin: r = 0.254, p = 0.013), anxiety (neurotensin: r = 0.265, p = 0.009; xenin: r = 0.257, p = 0.012), depressiveness (neurotensin: r = 0.281, p = 0.006; xenin: r = 0.241, p = 0.019) and eating disorder symptoms (neurotensin: r = 0.276, p = 0.007; xenin: r = 0.26, p = 0.011), whereas, men did not (p > 0.05).

Conclusion

Neurotensin and xenin plasma levels of female obese patients are positively correlated with perceived stress, anxiety, depressiveness, and eating disorder symptoms. These associations could be influenced by higher prevalence of mental disorders in women and by sex hormones. In men, no correlations were observed, which points toward a sex-dependent regulation.

Association of Obstructive Sleep Apnea With the Risk of Male Infertility in Taiwan

IMPORTANCE

Obstructive sleep apnea (OSA) has been proposed as a risk factor in infertility. However, to date, the association between OSA and male infertility has not been examined in a population-based study.

OBJECTIVE

To investigate the risk factor of OSA in male infertility and the outcome of OSA treatment for the risk of male infertility.

DESIGN, SETTING, AND PARTICIPANTS

This case-control population-based study collected data from the Longitudinal Health Insurance Database, a subset of the National Health Insurance Research Database in Taiwan. Male patients with a diagnosis of infertility and at least 3 outpatient visits or 1 hospitalization between January 1, 2000, and December 31, 2013, were included and matched by age, sex, and date of infertility diagnosis with individuals without an infertility diagnosis. Data analysis was performed from October 22, 2018, to April 22, 2019.

EXPOSURES

Patients with male infertility and randomly selected patients without male infertility were matched using a 1:4 propensity score matching ratio.

MAIN OUTCOMES AND MEASURES

A primary outcome was the risk factor of OSA (diagnosed through polysomnography). A secondary outcome was the association of the risk of male infertility with OSA exposure time interval (short term, middle term, and long term) and OSA management (ie, none, continuous positive airway pressure, uvulopalatopharyngoplasty, or both).

RESULTS

A total of 4607 male patients with infertility (mean [SD] age, 34.18 [5.44] years) and 18 428 control patients (mean [SD] age, 34.28 [5.81] years) were included. In the multivariate conditional logistic regression analysis, OSA was an independent risk factor associated with infertility (adjusted odds ratio [OR], 1.24; 95% CI, 1.10-1.64; P = .003). The absolute risk was 0.204 (95% CI, 0.092-0.391). For patients with OSA in the group without treatment, the adjusted OR was 1.80 (95% CI, 1.56-2.07; P < .001) for infertility compared with patients without OSA.

CONCLUSIONS AND RELEVANCE

Results of this study support the hypothesis that OSA increases the risk of infertility in male patients, and the risk is associated with the OSA exposure time. Furthermore, no OSA management or treatment is associated with a higher infertility risk.

A decrease of docosahexaenoic acid in testes of mice fed a high-fat diet is associated with impaired sperm acrosome reaction and fertility

Obesity is a major worldwide health problem that is related to most chronic diseases, including male infertility. Owing to its wide impact on health, mechanisms underlying obesity-related infertility remain unknown. In this study, we report that mice fed a high-fat diet (HFD) for over 2 months showed reduced fertility rates and increased germ cell apoptosis, seminiferous tubule degeneration, and decreased intratesticular estradiol (E2) and E2-to-testosterone ratio. Interestingly, we also detected a decrease in testicular fatty acid levels, behenic acid (C22:0), and docosahexaenoic acid (DHA, 22:6n-3), which may be related to the production of dysfunctional spermatozoa. Overall, we did not detect any changes in the frequency of seminiferous tubule stages, sperm count, or rate of in vitro capacitation. However, there was an increase in spontaneous and progesterone-induced acrosomal exocytosis (acrosome reaction) in spermatozoa from HFD-fed mice. These data suggest that a decrease in E2 and fatty acid levels influences spermatogenesis and some steps of acrosome biogenesis that will have consequences for fertilization. Thus, our results add new evidence about the adverse effect of obesity in male reproduction and suggest that the acrosomal reaction can also be affected under this condition.

Diet during early life defines testicular lipid content and sperm quality in adulthood

Childhood obesity is a serious concern associated with ill health later in life. Emerging data suggest that obesity has long-term adverse effects upon male sexual and reproductive health, but few studies have addressed this issue. We hypothesized that exposure to high-fat diet during early life alters testicular lipid content and metabolism, leading to permanent damage to sperm parameters. After weaning (day 21 after birth), 36 male mice were randomly divided into three groups and fed with a different diet regimen for 200 days: a standard chow diet (CTRL), a high-fat diet (HFD) (carbohydrate: 35.7%, protein: 20.5%, and fat: 36.0%), and a high-fat diet for 60 days, then replaced by standard chow (HFD_t). Biometric and metabolic data were monitored. Animals were then euthanized, and tissues were collected. Epididymal sperm parameters and endocrine parameters were evaluated. Testicular metabolites were extracted and characterized by 1H-NMR and GC-MS. Testicular mitochondrial and antioxidant activity were evaluated. Our results show that mice fed with a high-fat diet, even if only until early adulthood, had lower sperm viability and motility, and higher incidence of head and tail defects. Although diet reversion with weight loss during adulthood prevents the progression of metabolic syndrome, testicular content in fatty acids is irreversibly affected. Excessive fat intake promoted an overaccumulation of proinflammatory n-6 polyunsaturated fatty acids in the testis, which is strongly correlated with negative effects upon sperm quality. Therefore, the adoption of high-fat diets during early life correlates with irreversible changes in testicular lipid content and metabolism, which are related to permanent damage to sperm quality later in life.

Research progress on the relationship between sex hormone-binding globulin and male reproductive system diseases

Sex hormone-binding globulin, also known as testosterone-estradiol-binding globulin, is a multifunctional protein synthesised by hepatocytes. Sex hormone-binding globulin specifically binds and transports sex hormones to regulate plasma bioactive sex hormone levels and affects their bioavailability. As male sex hormone expression is dominated by testosterone, the binding of sex hormone-binding globulin with testosterone leads to the reduction in bioavailable testosterone, which cannot fulfil its physiological roles, thereby resulting in male infertility, erectile and gonadal dysfunction, prostate cancer and other male reproductive system diseases. Sex hormone-binding globulin may be involved in the pathogenesis of male reproductive system diseases, seriously affecting the quality of life of men. In this article, we review the association between sex hormone-binding globulin and male reproductive system diseases.

Association of polymorphism c.-124G>A and c.-16 C>T in the promoter region of human INHA gene with altered sperm parameters; A pilot study

OBJECTIVE

The objective of this was to demonstrate the association of Inhibin α (INHα) c.-124G>A and INHα-c.-16 C>T polymorphisms with altered sperm parameters in a selected male population of Karachi, Pakistan.

STUDY DESIGN & SETTINGS

In this pilot study, male subjects were stratified on the basis of the WHO criteria for altered sperm parameters; 83 (cases-altered sperm parameters) and 30 (controls-normal sperm parameters) subjects were included for analysis of INHα-c.124G>A polymorphism and 88 (cases) and 38 (controls) were analysed for INHα -c-16 C>T polymorphism. Genotyping of INHα-c.-124G>A and INHα-c.-16 C>T was performed by PCR-RFLP, genotype distribution in Hardy-Weinberg equilibrium was evaluated by binary logistic regression model.

RESULTS

For the c.-124G>A polymorphism in INHα gene, frequency of the three major genotypes in controls was: GG: 80.0%, GA: 20.0% and AA: 0% and in cases was: GG: 59.0%, GA: 30.2% and AA: 10.8%. The GG genotype was significantly associated with male infertility (P < .045, OR = 2.776, 95% CI = 1.025-7.513) while the GA genotype was not significantly associated with infertility (P < .290 OR = 0.580, 95% CI = 0.211-1.593). Frequency of mutant AA genotype was 10.8% in cases (altered sperm parameters) and absent (0%) in normal sperm parameter (controls). The frequencies of three major genotypes CC, CT and TT did not show any significant difference between cases and controls (P > .05).

CONCLUSION

The results from our study exhibited a significant association of c.-124G>A polymorphism in the INHα gene promoter region with male infertility in the Pakistani population. A significant association of c.-16 C>T polymorphism with male infertility, however, was not observed. Further large-scale studies should be conducted to confirm this association.

Association between obesity-associated markers and semen quality parameters and serum reproductive hormones in Chinese infertile men

BACKGROUND

The current evidence on the association between obesity-associated markers and semen quality, serum reproductive hormones and lipids remains inconsistent. In this study, we tested the hypothesis that, in infertile Chinese men, body mass index (BMI) negatively correlates with sperm concentration, serum total testosterone (TT), and high-density lipoprotein cholesterol (HDL-C). The relationship between other obesity-associated markers and semen quality parameters, serum reproductive hormones, lipids and leptin were also investigated.

METHODS

181 Chinese infertile men were recruited from September 2018 to September 2019. Their obesity-associated markers, semen parameters, and serum reproductive hormones, lipids and leptin were detected. Statistical analysis was performed to assess the relationship between obesity-associated markers and semen quality, serum reproductive hormones, lipids and leptin.

RESULT(S)

Statistically negative correlation was found between other obesity-associated markers (e.g. waist-to-hip ratio and waist-to-height ratio) and semen parameters (e.g. sperm concentration, ratio of progressive motility and ratio of non-progressive motility), while no significant correlation was found between BMI and semen quality, serum reproductive hormones, lipids and leptin. Ratio of morphologically normal sperm was negatively correlated with serum lipids including total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), leptin and seminal superoxide dismutase. Ratio of progressive sperm, sperm concentration and ratio of morphologically normal sperm exhibited significantly lower values in overweight group than normal group. Estradiol (E2) and E2/TT were significantly higher in obese group than normal group, while TT level was significantly lower in obese group than normal group. Univariate and multivariate analysis indicated that TC was significantly associated with BMI. Serum leptin concentration was positively correlated with seminal leptin concentration in overweight and obese groups.

CONCLUSION(S)

No significant correlation was found between BMI and sperm concentration, serum TT and HDL-C, while other obesity-associated markers were found to negatively correlate with sperm concentration, ratio of progressive motility and ratio of non-progressive motility. Statistically significant correlations between serum reproductive hormones, lipids and leptin also existed in Chinese infertile men.

The Impact of Obesity on Various Semen Parameters and Sex Hormones in Iranian Men with Infertility: A Cross-Sectional Study

Objective

The aim of this study was to examine the correlations between body mass index (BMI) and waist circumference (WC) and semen parameters (semen volume, sperm count, motility, and morphology) and sex hormones in Iranian men with infertility.

Materials and Methods

In this cross-sectional study, a total of 119 male patients who had lived as a partner in an infertile couple for at least 1 year, after regular unprotected sexual intercourse in their married life were investigated. BMI and WC were assessed, and a morning blood sample was taken assessing serum levels of testosterone (T), sex hormone-binding globulin (SHBG), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2) and leptin. Semen-analysis parameters were also measured.

Results

Based on BMI and WC, the sperm count, total motility and progressive sperm were significantly lower in overweight and obese infertile males compared to that in normal weight infertile males and those with WC<102 cm. In addition, the fraction of sperm with abnormal morphology was significantly higher in infertile men with WC>102 cm compared to that in those with WC<102 cm. Moreover serum levels of LH, FSH, and leptin were significantly higher in overweight and obese infertile males compared to that in normal weight infertile males and those with WC<102 cm. Moreover serum level of E2 was significantly higher in obese infertile males compared to the normal weight infertile males and in those with WC>102 cm compared to the WC<102 cm. Furthermore, serum level of T was significantly lower in obese infertile males compared to the overweight infertile males and in those with WC>102 cm compared to the WC<102 cm. The mean of T/E2 ratio also was significantly lower in obese infertile males vs overweight and normal weight infertile males and in those with WC>102 cm compared to the WC<102 cm.

Conclusion

We concluded that overweight and obesity in infertile men compared to those with normal weight may worsen the infertility situation.

Is perception of inability to procreate a temporal phenomenon?: A longitudinal exploration of changes and determinants among women and men of reproductive age in Germany

Continued postponement of births and increasing use of reproductive medicine enhance the relevance of infertility and related perceptions for fertility research. Fertility researchers tend to assume that an existing perception of inability to procreate is a stable trait among persons of reproductive age. This assumption is questionable from a life course perspective and has not been thoroughly investigated. Therefore we investigate the prevalence, stability, and correlates of perceived inability to procreate. We apply between-within logit models to annual panel data (2008-2015) to study variation in perceived inability to procreate within individuals over time and between individuals. We find that approximately every 20th person of reproductive age is affected. There is considerable instability among those who ever perceive an inability to procreate: On average, 39 % of women and 48 % of men who perceive an inability in one year change to not perceiving an inability in the next year. Multivariate analysis shows that increases in age and perception of one's partner as unable to procreate are associated with higher odds of perceiving an inability to procreate. Not using contraception is associated with higher odds of perceiving an inability to procreate. Perceived procreative ability further differs by parity, level of education, immigration background, and religious denomination. In summary, perception of inability to procreate is a temporal phenomenon that is shaped by lifecourse contexts and social group differences.

The impact of body mass index on reproductive hormones, testosterone/estradiol ratio and semen parameters

Introduction

The aim of this study was to evaluate the relationship between body mass index (BMI) and sperm parameters and reproductive hormone levels in patients with no known risk factors for infertility.

Material and methods

Four hundred patients who met the study's inclusion criteria were divided into three groups according to their BMI values as normal weight (BMI: 18.5-24.9 kg/m²), overweight (BMI 25-29.9 kg/m²), and obese (BMI ≥30 kg/m²). Semen parameters, reproductive hormone levels and testosterone/estradiol ratio were compared retrospectively between the groups.

Results

There was no significant difference between the groups in terms of age and infertility period. The mean BMI of all the patients was 26.6 ±4.08, and the BMI in the normal, overweight and obese groups were 22.6 ±1.7, 27.4 ±1.3, and 33.4 ±2.9, respectively (p <0.001). There was no significant difference between the groups in terms of serum follicle stimulating hormone, luteinizing hormone, estradiol, prolactin, semen volume, sperm concentration, total sperm count, and progressive and total motility. Serum testosterone (T) level and testosterone/estradiol (T/E2) ratio were significantly higher in the normal BMI group (p <0.001).

Conclusions

Adipose tissue increase was not significantly correlated with change in the semen parameters and it was negatively correlated with T levels and T/E2 ratio.

Features of the metabolic syndrome in late adolescence are associated with impaired testicular function at 20 years of age

STUDY QUESTION

Are early signs of metabolic disorder in late adolescence associated with features of impaired testicular function many years before the majority seek parenthood?

SUMMARY ANSWER

Adolescents with features of metabolic disorder at 17 years, or insulin resistance (IR) at 20 years of age, show impaired testicular function and altered hormone levels compared to those without metabolic disorder.

WHAT IS KNOWN ALREADY

Controversial evidence suggests a recent decline in sperm production potentially linked to environmental influences, but its cause remains unclear. Concomitant increases in obesity and diabetes suggest that lifestyle factors may contribute to this decline in testicular function. Although obesity has been associated with adverse testicular function in some studies, it remains unclear whether poor testicular function merely reflects, or causes, poor metabolic health. If metabolic disorder were present in adolescence, prior to the onset of obesity, this may suggest that metabolic disorder maybe a precursor of impaired testicular function.

STUDY DESIGN, SIZE, DURATION

The Western Australian Pregnancy Cohort (Raine) Study is a longitudinal study of children born in 1989-1991 who have undergone detailed physical assessments since birth (1454 male infants born). At 17 years of age, 490 boys underwent a hepatic ultrasound examination, serum cytokine assessment (n = 520) and a metabolic assessment (n = 544). A further metabolic assessment was performed at 20 years (n = 608). Testicular assessment was performed at 20 years; 609 had reproductive hormones measured, 404 underwent a testicular ultrasound and 365 produced a semen sample.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Testicular volume was estimated by ultrasonography, and semen analysis was performed according to World Health Organization guidelines. Concentrations of LH, FSH and inhibin B (inhB) in serum were measured by immunoassay and total testosterone by liquid chromatography-mass spectrometry.At 17 years of age, a liver ultrasound examination was performed to determine the presence of non-alcoholic fatty liver disease (NAFLD), and serum analysed for the cytokines interleukin-18 and soluble tumour necrosis factor receptor 1 and 2 (sTNFR1, sTNFR2).At 17 and 20 years of age, fasting blood samples were analysed for serum liver enzymes, insulin, glucose, triglycerides (TG), total cholesterol, high density lipoprotein and low density lipoprotein cholesterol, high sensitivity C-reactive protein and uric acid. The homoeostatic model assessment (HOMA) was calculated and approximated IR was defined by a HOMA >4. Anthropometric data was collected and dual energy X-ray absorptiometry measurement performed for lean and total fat mass. As at this young age the prevalence of metabolic syndrome was expected to be low, a two-step cluster analysis was used using waist circumference, TGs, insulin, and systolic blood pressure to derive a distinct high-risk group with features consistent with the metabolic syndrome and increased cardiometabolic risk.

MAIN RESULTS AND THE ROLE OF CHANCE

Men at age 17 years with increased cardiometabolic risk had lower concentrations of serum testosterone (medians: 4.0 versus 4.9 ng/mL) and inhB (193.2 versus 221.9 pg/mL) (P < 0.001 for both) compared to those within the low risk metabolic cluster. Men with ultrasound evidence of NAFLD (n = 45, 9.8%) had reduced total sperm output (medians: 68.0 versus 126.00 million, P = 0.044), testosterone (4.0 versus 4.7 ng/mL, P = 0.005) and inhB (209.1 versus 218.4 pg/mL, P = 0.032) compared to men without NAFLD.Men with higher concentrations of sTNFR1 at 17 years of age had a lower sperm output and serum concentration of inhB, with an increase in LH and FSH (all P < 0.05 after adjustment for age, BMI, abstinence and a history of cryptorchidism, varicocele, cigarette smoking, alcohol and drug use), compared to those without an elevated sTNFR1. Multivariable regression analysis, adjusting for confounders, demonstrated that men in the high-risk metabolic cluster at 20 years had a lower serum testosterone and inhB (P = 0.003 and P = 0.001, respectively). A HOMA-IR > 4 was associated with a lower serum testosterone (P = <0.001) and inhB (P = 0.010) and an increase in serum FSH (P = 0.015).

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the sample size and multiple comparisons, and causality cannot be proven from an observational study. Due to a 3-year interval between some metabolic assessments and assessment of testicular function, we cannot exclude the introduction of a bias into the study, as some of the participants and their testicular function will not have been fully mature at the 17-year assessment.

WIDER IMPLICATIONS OF THE FINDINGS

Irrespective of a proven causation, our study findings are important in that a significant minority of the men, prior to seeking parenthood, presented co-existent features of metabolic disorder and signs of testicular impairment. Of particular note is that the presence of NAFLD at 17 years of age, although only present in a minority of men, was associated with an almost 50% reduction in sperm output at 20 years of age, and that the presence of IR at 20 years was associated with a 20% reduction in testicular volume.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Australian NHMRC (Grant Numbers 634457, 35351417 and 403981) and received support from the Raine Medical Research Foundation, The Telethon Kids Institute, University of Western Australia, Women and Infants Research Foundation, Curtin University and Edith Cowan University. D.A.D., J.E.D., N.M., L.A.A., R.-C.H., T.A.M., J.K.O., L.J.B. have nothing to declare. R.J.H. is Medical Director of Fertility Specialists of Western Australia, has equity interests in Western IVF, and has received grant support from MSD, Merck-Serono and Ferring Pharmaceuticals. RMcL has equity interests in the Monash IVF Group. R.J.N. has equity interests in FertilitySA, and has received grant support from Merck Serono and Ferring Pharmaceuticals. D.J.H. has received institutional grant funding (but no personal income) for investigator-initiated testosterone pharmacology studies from Lawley and Besins Healthcare and has provided expert testimony to anti-doping tribunals and for testosterone litigation.This abstract was awarded the Fertility Society of Australia clinical exchange award for the oral presentation at ESHRE, Barcelona, in 2018.

The effect of excess body fat on female and male reproduction

The dramatic increase in the prevalence of obesity coincides with a decline in reproductive health indices in both sexes. Energy excess mediates changes to the regulatory mechanisms of the reproductive system. Obese individuals exhibit increased estrogen concentrations, due to the overexpression of aromatase in the adipose tissue; via a negative feedback loop, men present with symptoms of hypogonadotropic hypogonadism. These hormonal changes, along with increased oxidative stress, lipotoxicity and disturbances in the concentrations of adipokines, directly affect the gonads, peripheral reproductive organs and the embryo. Clinical evidence is somewhat contradicting, with only some studies advocating worse semen parameters, increased incidence of erectile dysfunction, increased doses of ovulation induction medications, and worse live birth rates in assisted reproductive technology (ART) cycles in obese individuals compared with those of normal weight. Similar conclusions are drawn about patients with insulin resistance syndromes, namely polycystic ovary syndrome (PCOS). As far as treatment options are concerned, lifestyle changes, medical therapy and bariatric surgery may improve the reproductive outcome, although the evidence remains inconclusive. In this review, we summarize the evidence on the association of obesity and reproductive health on both the molecular and the clinical level, and the effect of weight-loss interventions on reproductive potential.

Leptin and its actions on reproduction in males

Leptin, an adipocyte-derived hormone, serves numerous physiological functions in the body, particularly during puberty and reproduction. The exact mechanism by which leptin activates the gonadotropin-releasing hormone (GnRH) neurons to trigger puberty and reproduction remains unclear. Given the widespread distribution of leptin receptors in the body, both central and peripheral mechanisms involving the hypothalamic-pituitary-gonadal axis have been hypothesized. Leptin is necessary for normal reproductive function, but when present in excess, it can have detrimental effects on the male reproductive system. Human and animal studies point to leptin as a link between infertility and obesity, a suggestion that is corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The major pathways causing these abnormalities remain unidentified; however, these adverse effects have been attributed to leptin-induced increased oxidative stress because they are prevented by concurrently administering melatonin. Studies on leptin and its impact on sperm function are highly relevant in understanding and managing male infertility, particularly in overweight and obese men.

Effectiveness of a therapeutic multiple-lifestyle intervention taking into account the periconceptional environment in the management of infertile couples: study design of a randomized controlled trial - the PEPCI study

BACKGROUND

Infertility is defined as the inability to conceive after 12 months of unprotected intercourse. It affects approximately one in six couples seeking pregnancy in France or western countries. Many lifestyle factors of the couples' pre and peri-conceptional environment (weight, diet, alcohol, tobacco, coffee, drugs, physical activity, stress, sleep…) have been identified as risk factors for infertility in both males and females. The high prevalence rates of unhealthy diets and lifestyles in the reproductive population of industrialized countries are worrisome. Nevertheless, adoption of a healthy lifestyle may improve fertility but lifestyle changes are difficult to achieve and to maintain due notably to behavioral factors.

METHODS

Consequently, we decided to propose an interventional study aimed at improving the quality of life of infertile couples before the start of assisted reproductive technology treatment. It is a randomized controlled multicentre trial. Both members of the couples are involved in an integrated global care program (PEPCI for "Parcours Environnement PériConceptionnel en Infertilité") vs. usual care. This global intervention not only considers diet and/or physical activity but follows a holistic approach, including a multidisciplinary assessment to address complete physical, psychological and social well-being. According to patient needs, this includes interventions on weight, exercise, diet, alcohol and drugs, mental and social health.

DISCUSSION

The main objective of trial is to demonstrate that periconceptional multidisciplinary care has a positive impact on reproductive functions. We will also focus on feasibility, acceptance, compliance and conditions of success of a multifaceted lifestyle intervention.

TRIAL REGISTRATION

The trial was registered at ClinicalTrials.gov, Identifier: NCT02961907 on November 11, 2016.

Obesity and male infertility: Mechanisms and management

Obesity is considered a global health problem affecting more than a third of the population. Complications of obesity include cardiovascular diseases, type 2 diabetes mellitus, malignancy (including prostatic cancer), neurodegeneration and accelerated ageing. In males, these further include erectile dysfunction, poor semen quality and subclinical prostatitis. Although poorly understood, important mediators of obesity that may influence the male reproductive system include hyperinsulinemia, hyperleptinemia, chronic inflammation and oxidative stress. Obesity is known to disrupt male fertility and the reproduction potential, particularly through alteration in the hypothalamic-pituitary-gonadal axis, disruption of testicular steroidogenesis and metabolic dysregulation, including insulin, cytokines and adipokines. Importantly, obesity and its underlying mediators result in a negative impact on semen parameters, including sperm concentration, motility, viability and normal morphology. Moreover, obesity inhibits chromatin condensation, DNA fragmentation, increases apoptosis and epigenetic changes that can be transferred to the offspring. This review discusses the impact of obesity on the male reproductive system and fertility, including associated mechanisms. Furthermore, weight management strategies, lifestyle changes, prescription medication, and complementary and alternative medicine in the management of obesity-induced subfertility is discussed.

Do lifestyle practices impede male fertility?

Alongside an increasing prevalence of couple and male infertility, evidence suggests there is a global declining trend in male fertility parameters over the past few decades. This may, at least in part, be explained through detrimental lifestyle practices and exposures. These include alcohol and tobacco consumption, use of recreational drugs (e.g., cannabis, opioids and anabolic steroids), poor nutritional habits, obesity and metabolic syndrome, genital heat stress (e.g., radiation exposure through cell phones and laptops, prolonged periods of sitting, tight-fitting underwear and recurrent hot baths or saunas), exposure to endocrine-disrupting chemicals (e.g., pesticide residue, bisphenol A, phthalates and dioxins) and psychological stress. This review discusses these lifestyle practices and the current evidence associated with male infertility. Furthermore, known mechanisms of action are also discussed for each of these. Common mechanisms associated with a reduction in spermatogenesis and/or steroidogenesis due to unfavourable lifestyle practices include inflammation and oxidative stress locally or systemically. It is recommended that relevant lifestyle practices are investigated in clinical history of male infertility cases, particularly in unexplained or idiopathic male infertility. Appropriate modification of detrimental lifestyle practices is further suggested and recommended in the management of male infertility.