Effects of Overweight and Obesity on the Spermogram Values and Levels of Reproductive Hormones in the Male Population of the European North of Russia

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.

Study of Semen Quality, Reproductive Hormone Levels, and Lipid Levels in Men From Arkhangelsk, a City in North of European Russia

Male populations in the European North of Russia have not previously been investigated for semen quality. The aim of this study was to evaluate semen parameters, reproductive hormone levels, and lipid levels in volunteers from the general urban population of the European North of Russia, to compare the data published for men from the neighboring Northern or Eastern European countries, and to evaluate associations between sperm quality and serum hormonal and lipid levels. Ninety-nine volunteers aged 23-63 years residing in the city of Archangelsk were enrolled in the study. All men had blood samples drawn and completed a questionnaire concerning their health status and lifestyle; 90 men delivered semen samples. The medians for semen volume, sperm concentration, progressive motility, and normal morphology were 3.0 ml, 42.12 million/ml, 43.8%, and 6.5%, respectively. Sperm parameters below normal threshold values were found in 38.9% of participants. It seems that the sperm quality in our study group was slightly worse than in men from Finland, Norway, Sweden, or Estonia, but very similar to that in men from Denmark or Poland. The significant negative correlations of luteinizing hormone levels and positive correlations of inhibin B levels with sperm concentration and progressive motility were revealed. Higher levels of luteinizing hormone and lower levels of inhibin B were found in participants with impaired compared to normal sperm quality. No reliable links were found between serum total cholesterol, triglyceride, high and low-density lipoprotein cholesterol, and semen parameters.

Does obesity based on body mass index affect semen quality?-A meta-analysis and systematic review from the general population rather than the infertile population

Whether obesity affects the quality of semen has become the focus of research. However, there are some deficiencies in the past research, because the vast majority of known infertile patients were included in the study samples. Taking infertile men as the research object to analyse the impact of obesity on semen quality, which cannot accurately prove that the impact on semen quality is caused by obesity, because the impact on semen quality may also be caused by other factors. Therefore, we selected ordinary obese men rather than infertile patients to conduct a systematic review and meta-analysis of the effects of obesity on semen parameters. The results showed that obesity had no effect on sperm concentration (SMD: -0.15, 95% CI: -0.32 ~ 0.02, p = .088) and percentage of normal sperm morphology (SMD: -0.17, 95% CI: -0.66 ~ 0.32, p = .487), but decreased semen volume (SMD: -0.32, 95% CI: -0.52 ~ -0.12, p = .002), total sperm number (SMD: -0.77, 95% CI: -1.31 ~ -0.23, p = .005), percentage of forward progression (SMD: -0.95, 95% CI: -1.7 ~ -0.19, p = .014) and percentage of viability (SMD: -0.812, 95% CI: -1.532 ~ -0.093, p = .027). Therefore, obesity affects semen quality to a certain extent, and maintaining normal weight may be one of the effective ways to improve male fertility.

The impact of BMI on sperm parameters and the metabolite changes of seminal plasma concomitantly

The development of male infertility increased rapidly worldwide, which coinciding with the epidemic of obesity. However, the impact of weight abnormalities on sperm quality is still contestable. To assess the correlation between BMI and sperm parameters, we searched relevant articles in PubMed, Embase, Web of science, and Wanfang database published until June 2015 without language restriction. Otherwise, we also recruited some participants who attended fertility clinic as well as some general populations in this report. We performed a systematic review and meta-analysis about BMI and sperm parameters containing total sperm count, concentration, semen volume and sperm motility (overall and progressive). Metabolomic analysis of seminal plasma was performed to explore the mechanism from a new perspective. This study found standardized weighted mean differences (SMD) in sperm parameters (total sperm count, sperm concentration, and semen volume) of abnormal weight groups decreased to different degree compared to normal weight. Dose-response analysis found SMD of sperm count, sperm concentration and semen volume respectively fell 2.4%, 1.3% and 2.0% compared with normal weight for every 5-unit increase in BMI. Metabolomic analysis of seminal plasma showed that spermidine and spermine were likely to play a vital role in the spermatogenesis progress. This systematic review with meta-analysis has confirmed there was a relationship between BMI and sperm quality, suggesting obesity may be a detrimental factor of male infertility.

Overweight in young males reduce fertility in rabbit model

Semen quality has certainly declined over the past few decades, possibly owing to modern lifestyle factors. In this sense, the role of overweight and obesity in the development of subfertility in males has generated a considerable amount of interest in recent years. However, there is no consensus on whether overweight or obesity impaired sperm quality. Thus, based on the ongoing debate about risk factors for subfertility associated with overweight and obesity in men, this study was designed to investigate the effect of overweight on sperm quality parameters and fertility success in randomized controlled trial in a rabbit model. Fourteen male rabbits were randomly assigned to a control group in which nutritional requirements were satisfied or a group fed to satiety from 12 to 32 weeks of age. At 24 weeks of age, semen samples were analysed weekly by conventional semen analysis for 8 weeks. In addition, during the trial female rabbits were artificially inseminated by each male to assess the fertility success and the number of offspring. Young males fed to satiety were associated with a significant increase in body weight (13.6% overweight) and perirenal fat thickness (5%). Male overweight presented a significant decrease in sperm concentration. There were no differences in the remaining sperm parameters. However, male overweight showed a clear and significant decrease in fertility success (control group, 64±8.9% versus fed to satiety group, 35±9.2%), but not in the number of offspring. Taken together, our findings provide new evidence on the loss of fertility induced by overweight in males.

The impact of obesity on male fecundity: a Brazilian study

Introduction

Obesity has become a major problem in most developed countries. Infertility ranks high among the issues brought by excessive weight gain, particularly as it may affect male sexual function. This study investigated a population of Brazilian infertile men in an attempt to establish a relationship between obesity and infertility.

Methods

A total of 153 infertile men had their anthropometric data collected and were divided into groups according to their body mass index and waist circumference measurements. Sperm parameters including sperm count, concentration, morphology, and motility were compared.

Results

Multivariate analysis failed to show a positive correlation between excessive weight gain or increased waist circumference, and sperm alterations in a population of infertile men.

Conclusions

The findings described in this study support the idea that there is no association between obesity and semen alterations in a population of infertile men.

Spermatogenesis in humans and its affecting factors

Spermatogenesis is an extraordinary complex process. The differentiation of spermatogonia into spermatozoa requires the participation of several cell types, hormones, paracrine factors, genes and epigenetic regulators. Recent researches in animals and humans have furthered our understanding of the male gamete differentiation, and led to clinical tools for the better management of male infertility. There is still much to be learned about this intricate process. In this review, the critical steps of human spermatogenesis are discussed together with its main affecting factors.

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.

Paternal obesity negatively affects male fertility and assisted reproduction outcomes: a systematic review and meta-analysis

This systematic review investigated the effect of paternal obesity on reproductive potential. Databases searched were Pubmed, Ovid, Web of Science, Scopus, Cinahl and Embase. Papers were critically appraised by two reviewers, and data were extracted using a standardized tool. Outcomes were: likelihood of infertility, embryo development, clinical pregnancy, live birth, pregnancy viability, infant development, sperm; concentration, morphology, motility, volume, DNA fragmentation, chromatin condensation, mitochondrial membrane potential (MMP), and seminal plasma factors. Thirty papers were included, with a total participant number of 115,158. Obese men were more likely to experience infertility (OR = 1.66, 95% CI 1.53-1.79), their rate of live birth per cycle of assisted reproduction technology (ART) was reduced (OR = 0.65, 95% CI 0.44-0.97) and they had a 10% absolute risk increase of pregnancy non-viability. Additionally, obese men had an increased percentage of sperm with low MMP, DNA fragmentation, and abnormal morphology. Clinically significant differences were not found for conventional semen parameters. From these findings it can be concluded that male obesity is associated with reduced reproductive potential. Furthermore, it may be informative to incorporate DNA fragmentation analysis and MMP assessment into semen testing, especially for obese men whose results suggest they should have normal fertility.

Male obesity is associated with changed spermatozoa Cox4i1 mRNA level and altered seminal vesicle fluid composition in a mouse model

The rate of obesity among men of reproductive age has tripled in the last three decades. Previously, we demonstrated that paternal obesity resulted in impaired preimplantation developmental kinetics, compromised post-compaction metabolism and decreased blastocyst cell number when embryos were generated in vivo. Subsequently, using in vitro fertilization we found embryos of obese males to have altered metabolism before compaction, reduced inner cell mass cell number and retarded fetal development--the difference between these two studies being the method of embryo generation and the presence or absence of seminal plasma, respectively. Here, we hypothesize that both sperm and seminal plasma are affected by obesity, compromising embryogenesis and pregnancy health in a cumulative manner. Epididymal sperm and seminal vesicle fluid were collected from normal and obese C57BL/6 mice. RNA and DNA were extracted from spermatozoa for qPCR and global methylation analysis, respectively. Proteomic (Luminex) and metabolomic (GC-MS) techniques were employed to analyse the composition of seminal vesicle fluid. Nuclear encoded cytochrome c oxidase subunit IV isoform 1 (Cox4i1) of the terminal enzyme in the mitochondrial respiratory chain demonstrated significantly increased RNA levels in the sperm of obese males (P< 0.05). Quantitative seminal plasma analysis identified significant changes in levels of the hormones insulin, leptin and estradiol between normal and obese males (P < 0.05). Further, the metabolite composition of seminal vesicle fluid was significantly affected by obesity. Consequently, this study has determined that obesity affects both sperm and seminal plasma composition. The interaction between sperm and seminal plasma warrants further analysis.