Relation between male obesity and male infertility in a Tunisian population

Association between body mass index and semen quality: a systematic review and meta-analysis

The continuous decline of human semen quality during the past decades has drawn much concern globally. Previous studies have suggested a link between abnormal BMI and semen quality decline, but the results remain inconsistent. This systematic review and meta-analysis aimed to evaluate the association between body mass index (BMI) and semen quality. We searched PubMed, Embase, and Web of Science for eligible studies from inception to April 17, 2022. We considered men with BMI < 25.0 kg/m2 as the reference and calculated the pooled weighted mean difference of men with overweight (BMI 25.0-29.9 kg/m2), obesity (BMI ≥ 30.0 kg/m2), class I obesity (BMI 30.0-34.9 kg/m2), and class II/III obesity (BMI ≥ 35.0 kg/m2). A total of 5070 articles were identified, of which 50 studies were included (71,337 subjects). Compared with men with BMI < 25.0 kg/m2, men with obesity had an average reduction of 0.24 ml in semen volume, 19.56 × 106 in total sperm number, 2.21% in total motility, 5.95% in progressive motility, and 1.08% in normal forms, respectively, while men with overweight had an average reduction of 0.08 ml in semen volume and 2.91% in progressive motility, respectively. The reduction of semen quality was more pronounced among men with obesity than that among men with overweight. Moreover, significant reductions in semen quality were identified in men with different classes of obesity, which were more pronounced in men with class II/III obesity than that in men with class I obesity. Across men from the general population, infertile or subfertile men, and suspiciously subfertile men, we identified significant semen quality reductions in men with obesity/overweight. In conclusion, obesity and overweight were significantly associated with semen quality reductions, suggesting that maintaining normal weight may help prevent semen quality decline.

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

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

The association between body mass index and varicocele: A meta-analysis

Objective:

Recently, several studies have found that obesity had a protective effect against varicocele, but no meta-analysis has confirmed this finding. Therefore, we conducted this meta-analysis to investigate the association between body mass index (BMI) and varicocele.

Material and Methods:

We searched for studies in PubMed, Science Direct and the Cochrane Library from inception until February 2018. The association between BMI and varicocele was assessed by pooling the odds ratios (ORs).

Results:

Eleven eligible studies with a total study population of 1.376.658 participants were included in our analysis. According to BMI, the subjects were defined as belonging to the obese, overweight and underweight groups. Our results showed that the obese group had a lower risk of varicocele when compared with the normal weight group (odds ratio [OR] 0.46, 95% confidence intervals [CIs] 0.37-0.58). Additionally, an overweight BMI had a protective effect against varicocele (OR 0.70, 95% CIs, 0.56-0.86). However, underweight patients had a more than 30% higher risk of varicocele (OR 1.31, 95% CI, 1.04-1.64). Furthermore, there was no publication bias in any of the analyses.

Conclusions:

Our study demonstrates that BMI is negatively associated with the presence of varicocele.

Male adiposity, sperm parameters and reproductive hormones: An updated systematic review and collaborative meta-analysis

The present updated systematic review and meta-analysis aims to summarize the evidence from published studies with low risk for any important bias (based on methodological quality assessment) investigating the potential associations of adiposity with sperm quality and reproductive hormones. We conducted a systematic search of the literature published in MEDLINE-PubMed and EMBASE through June 2019. Based on the criteria in our review, 169 eligible publications were used for data abstraction. Finally, 60 articles were included in the qualitative analysis and 28 in the quantitative analysis. Our systematic review results indicated that overweight and/or obesity were associated with low semen quality parameters (i.e., semen volume, sperm count and concentration, sperm vitality and normal morphology) and some specific reproductive hormones (e.g., inhibin B, total testosterone and sex hormone-binding globulin). Overweight and/or obesity were also positively associated with high estradiol concentrations. Meta-analysis indicated that overweight and/or obesity categories were associated with lower sperm quality (i.e., semen volume, sperm count and concentration, sperm vitality, total motility and normal morphology), and underweight category was likewise associated with low sperm normal morphology. In conclusion, our results suggest that maintaining a healthy body weight is important for increasing sperm quality parameters and potentially male fertility.

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.

Soy Isoflavones Improve the Spermatogenic Defects in Diet-Induced Obesity Rats through Nrf2/HO-1 Pathway

Soy isoflavones (SIF) are biologically active compounds of non-steroidal and phenolic properties that are richly present in soybeans, which can reduce the body weight and blood lipids of obese animals. Recently, SIF have been reported to affect reproductive ability in obese male rats. However, the specific mechanism has not been well defined. The aim of the current study was to study the possible mechanisms for the effect of SIF administration on obesity induced spermatogenic defects. Obese rats model induced by high-fat diets were established and gavage treated with 0, 50,150 or 450 mg of SIF/kg body weight/day for 4 weeks. Here, our research shows that obesity resulted in spermatogenic degeneration, imbalance of reproductive hormone, testicular oxidative stress and germ cell apoptosis, whereas evidently recovery effects were observed at 150 and 450 mg/kg SIF. We also have discovered that 150 and 450 mg/kg SIF can activate Nrf2/HO-1 pathway in control of Bcl-2, BAX and cleaved caspase-3 expression with implications in antioxidant protection. Our study indicates the potential mechanism of SIF regulating spermatogenic function in obese rats, and provides a scientific experimental basis for the regulation of biological function of obese male reproductive system by SIF.

Associations between male reproductive characteristics and the outcome of assisted reproductive technology (ART)

The present study was designed to investigate the relationships between indicators of male body mass index (BMI), age, reproductive hormone levels, semen parameters, and the outcomes of assisted reproductive technology (ART). The clinical data were collected from 636 couples who underwent ART between January, 2013 and December, 2015 at the reproductive center involved in our study. Pearson’s correlation or Spearman rank correlation was applied to establish the relevant correlation coefficients. The correlation between influence factors’ and pregnancy outcomes was analyzed using the Logistic regression model. Analyses were conducted using SPSS software. Male BMI was found to be negatively correlated with testosterone (T) (P<0.05), while follicle-stimulating hormone (FSH) was negatively correlated with semen parameters (P<0.05). Luteinizing hormone (LH) was found to be negatively correlated with total sperm count, normal sperm morphology, and abortion (all P<0.05). Clinical pregnancy was related to sperm concentration and female age (P<0.05), and live birth was found to be associated only with female age (P<0.05). Male BMI was associated with the secretion of reproductive hormones, but had no effect on sperm parameters or ART outcome. A higher male age was also negatively connected with the outcome of clinical pregnancy. Reproductive hormones were not associated with ART outcome. Sperm concentration and female age were important factors influencing ART clinical pregnancy, while the only significant factor influencing live birth was female age. Levels of obesity-related inflammatory indicators (i.e. free fatty acid (FFA), glutathione peroxidase (GSH-Px), human inhibin-B (IHNB), interleukin-1 (IL-1), insulin-like growth factor-1 (IGF-1), and reactive oxygen species (ROS)) also varied with degrees of BMI. The present study provides information on the associations between male reproductive characteristics and the outcome of ART, which may contribute to improved strategies to help couples achieve better pregnancy outcomes.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Male obesity and subfertility, is it really about increased adiposity?

The prevalence of overweight and obesity in reproductive-aged men is increasing worldwide, with >70% of men >18 years classified as overweight or obese in some western nations. Male obesity is associated with male subfertility, impairing sex hormones, reducing sperm counts, increasing oxidative sperm DNA damage and changing the epigenetic status of sperm. These changes to sperm function as a result of obesity, are further associated with impaired embryo development, reduced live birth rates and increased miscarriage rates in humans. Animal models have suggested that these adverse reproductive effects can be transmitted to the offspring; suggesting that men's health at conception may affect the health of their children. In addition to higher adiposity, male obesity is associated with comorbidities, including metabolic syndrome, hypercholesterolemia, hyperleptinemia and a pro-inflammatory state, all which have independently been linked with male subfertility. Taken together, these findings suggest that the effects of male obesity on fertility are likely multifactorial, with associated comorbidities also influencing sperm, pregnancy and subsequent child health.