BMI in relation to sperm count: an updated systematic review and collaborative meta-analysis

Early Life Events Predict Adult Testicular Function; Data Derived From the Western Australian (Raine) Birth Cohort

CONTEXT

The impact of early life events on testicular function in adulthood is not well understood.

OBJECTIVE

To study the early influences of fetal growth, exposures to cigarette smoke in utero and cord blood estrogens, and the influences of growth and adiposity in childhood through adolescence; on testicular function in adulthood.

DESIGN

Male members of the Western Australian Pregnancy Cohort (Raine) were contacted at 20-22 years of age. Of 913 contacted, 423 (56%) agreed to participate; 404 underwent a testicular ultrasound, 365 provided a semen sample, and reproductive hormones were measured (384). Fetal growth measurements (n = 137), umbilical cord estrogen concentrations (n = 128), cord testosterone (T) (n = 125), and child-adulthood growth charts (n = 395) were available.

RESULTS

Median sperm output for the 18.6% of men exposed in utero to smoking was lower than nonexposed (82.4 × 10(6) vs 123.1 × 10(6); P = .029). Sperm output in adulthood was inversely correlated with cord serum estradiol (P = .019) and estrone (P = .018). The sperm output of men whose cord blood estradiol and estrone were less than 50th percentile vs more than 50th percentile was 191.1 × 10(6) vs 100.5 × 10(6) (P = .002) and 190.0 × 10(6) vs 106.0 × 10(6) (P = .012), respectively. Men with favorable fetal growth patterns in utero were less likely to have total motile sperm counts within the lowest quartile (P = .011), and men born prematurely had reduced serum T levels in adulthood (13.4 vs 16.6nmol/L, P = .024). Consistent height above the 50th percentile for age through childhood was associated with larger adult mean testicular volume (P < .001). Optimal body mass index trajectory through childhood and adolescence was associated with larger testicular volume (P = .009) and higher serum inhibin B (P = .010) and T (P = .003) in adulthood.

CONCLUSIONS

Exposures to maternal smoking and higher cord blood estrogens at delivery were associated with a reduced sperm output in adulthood. Optimal adult testicular function depends on being born at or above average weight, and maintaining optimal growth and adiposity into adulthood.

Epigenetics in male reproduction: effect of paternal diet on sperm quality and offspring health

Epigenetic inheritance and its underlying molecular mechanisms are among the most intriguing areas of current biological and medical research. To date, studies have shown that both female and male germline development follow distinct paths of epigenetic events and both oocyte and sperm possess their own unique epigenomes. Fertilizing male and female germ cells deliver not only their haploid genomes but also their epigenomes, which contain the code for preimplantation and postimplantation reprogramming and embryonal development. For example, in spermatozoa, DNA methylation profile, DNA-associated proteins, protamine 1:protamine 2 ratio, nucleosome distribution pattern, histone modifications and other properties make up a unique epigenetic landscape. However, epigenetic factors and mechanisms possess certain plasticity and are affected by environmental conditions. Paternal and maternal lifestyle, including physical activity, nutrition and exposure to hazardous substances, can alter the epigenome and, moreover, can affect the health of their children. In male reproductive health, data are emerging on epigenetically mediated effects of a man's diet on sperm quality, for example through phytochemicals, minerals and vitamins, and nutritional support for subfertile men is already being used. In addition, studies in animal models and human epidemiological data point toward a transgenerational effect of the paternally contributed sperm epigenome on offspring health.

Effect of bariatric surgery on semen parameters and sex hormone concentrations: a prospective study

Obesity has become a major health concern, with a prevalence rate approaching epidemic states. An inverse relationship between men's body weight and semen parameters has been observed, suggesting a favourable role for weight loss in improving fertility. This prospective study included 46 patients undergoing sleeve gastrectomy, who were investigated with semen analysis and serum hormone tests before and 12 months after surgery. Patients were divided into three groups according to their initial sperm concentration; median loss of body mass index was used as a cut-off to further classify patients according to extent of weight loss. Patients' preoperative seminal investigations revealed azoospermia in 13 (28.3%), oligospermia in 19 (41.3%) and normal sperm concentration in 14 (30.4%). Overall, only serum testosterone significantly increased after surgery (P < 0.001). Between study groups, the increase in sperm concentration was statistically significant in men with azoospermia and oligospermia (both P < 0.05), whereas serum testosterone was statistically significant in all groups (P < 0.001). Changes in semen and hormone tests were not affected by the extent of weight loss experienced by patients. Weight loss from bariatric surgery had a favourable effect on serum testosterone levels and semen parameters of patients with pre-existing azoospermia and oligospermia.

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.

Metabolic syndrome in white European men presenting for primary couple's infertility: investigation of the clinical and reproductive burden

Despite complex interactions between obesity, dyslipidemia, hyperinsulinaemia, and the reproductive axis, the impact of metabolic syndrome on human male reproductive function has not been analysed comprehensively. Complete demographic, clinical, and laboratory data from 1337 consecutive primary infertile men were analysed. Health-significant comorbidities were scored with the Charlson Comorbidity Index (categorised 0 vs. 1 vs. 2 or higher). NCEP-ATPIII criteria were used to define metabolic syndrome. Semen analysis values were assessed based on the 2010 World Health Organisation (WHO) reference criteria. Descriptive statistics and logistic regression models tested the association between semen parameters and clinical characteristics and metabolic syndrome. Metabolic syndrome was found in 128 (9.6%) of 1337 men. Patients with metabolic syndrome were older (p < 0.001) and had a greater Charlson Comorbidity Index of 1 or higher (chi-square: 15.6; p < 0.001) compared with those without metabolic syndrome. Metabolic syndrome patients had lower levels of total testosterone (p < 0.001), sex hormone-binding globulin (p = 0.004), inhibin B (p = 0.03), and anti-Müllerian hormone (p = 0.009), and they were hypogonadal at a higher rate (chi-square: 32.0; p < 0.001) than patients without metabolic syndrome. Conversely, the two groups did not differ significantly in further hormonal levels, semen parameters, and rate of either obstructive or non-obstructive azoospermia. At multivariate logistic regression analysis, testicular volume (OR: 0.90; p = 0.002) achieved independent predictor status for WHO pathological semen concentration; conversely, age, Charlson Comorbidity Index scores, metabolic syndrome, and inhibin B values did not. No parameters predicted normal sperm morphology and total progressive motility. Metabolic syndrome accounts for roughly 9% of men presenting for primary couple's infertility. Although metabolic syndrome patients have a lower general male health status, semen analysis values seem independent of the presence of metabolic syndrome.

Fatty acid composition of spermatozoa is associated with BMI and with semen quality

High body mass index (BMI) is negatively associated with semen quality. In addition, the composition of fatty acids of spermatozoa has been shown to be important for their function. The aim of the study was to examine the association between BMI and the composition of spermatozoa fatty acids in men spanning a broad BMI range. We also analysed the relation between fatty acid composition of spermatozoa and semen characteristics, and the relationship between serum fatty acids and spermatozoa fatty acids. One hundred forty-four men with unknown fertility status were recruited from the general population, from couples with identified female infertility and from morbid obesity centres. Standard semen analysis (WHO) and sperm DNA integrity (DFI) analysis were performed. Fatty acid compositions were assessed by gas chromatography. When adjusted for possible confounders, BMI was negatively associated with levels of sperm docosahexaenoic acid (DHA) (p < 0.001) and palmitic acid (p < 0.001). The amount of sperm DHA correlated positively with total sperm count (r = 0.482), sperm concentration (r = 0.469), sperm vitality (r = 0.354), progressive sperm motility (r = 0.431) and normal sperm morphology (r = 0.265). A negative association was seen between DHA levels and DNA fragmentation index (r = -0.247). Levels of spermatozoa palmitic acid correlated positively with total sperm count (r = 0.227), while levels of linoleic acid correlated negatively (r = -0.254). When adjusted for possible confounders, only the levels of arachidonic acid showed positive correlation between spermatozoa and serum phospholipids (r = 0.262). Changes in the fatty acid composition of spermatozoa could be one of the mechanisms underlying the negative association between BMI and semen quality. The relationship between fatty acids of spermatozoa and serum phospholipids was minor, which indicates that BMI affects fatty acid composition of spermatozoa through regulation of fatty acid metabolism in the testis. The role of dietary intake of fatty acids on the spermatozoa fatty acid composition remains to be elucidated.

Gut Endotoxin Leading to a Decline IN Gonadal function (GELDING) - a novel theory for the development of late onset hypogonadism in obese men

Obesity is an increasing public health problem, with two-thirds of the adult population in many Western countries now being either overweight or obese. Male obesity is associated with late onset hypogonadism, a condition characterised by decreased serum testosterone, sperm quality plus diminished fertility and quality of life. In this paper we propose a novel theory underlying the development of obesity related hypogonadism- the GELDING theory (Gut Endotoxin Leading to a Decline IN Gonadal function). Several observational studies have previously reported an association between obesity related hypogonadism (low testosterone) and systemic inflammation. However, for the first time we postulate that the trans-mucosal passage of bacterial lipopolysaccharide (LPS) from the gut lumen into the circulation is a key inflammatory trigger underlying male hypogonadism. Obesity and a high fat/high calorie diet are both reported to result in changes to gut bacteria and intestinal wall permeability, leading to the passage of bacterial endotoxin (lipopolysaccharide- LPS) from within the gut lumen into the circulation (metabolic endotoxaemia), where it initiates systemic inflammation. Endotoxin is known to reduce testosterone production by the testis, both by direct inhibition of Leydig cell steroidogenic pathways and indirectly by reducing pituitary LH drive, thereby also leading to a decline in sperm production. In this paper we also highlight the novel evolutionary benefits of the GELDING theory. Testosterone is known to be a powerful immune-suppressive, decreasing a man's ability to fight infection. Therefore we postulate that the male reproductive axis has evolved the capacity to lower testosterone production during times of infection and resulting endotoxin exposure, decreasing the immunosuppressive influence of testosterone, in turn enhancing the ability to fight infection. While this response is adaptive in times of sepsis, it becomes maladaptive in the setting of "non-infectious" obesity related metabolic endotoxaemia.

Intake of Fruits and Vegetables with Low-to-Moderate Pesticide Residues Is Positively Associated with Semen-Quality Parameters among Young Healthy Men

BACKGROUND

Numerous studies have shown that occupational or environmental pesticide exposure can affect male fertility. There is less evidence, however, regarding any potentially adverse effects of pesticide residues in foods on markers of male fertility potential.

OBJECTIVES

We examined the relations between fruit and vegetable intake, considering pesticide residue status, and semen quality and serum concentrations of reproductive hormones in healthy young men.

METHODS

The Rochester Young Men's Study is a cross-sectional study that recruited men aged 18-22 y (n = 189) in Rochester, New York. Participants completed a questionnaire, provided a semen sample, had a blood sample drawn, and underwent a physical examination at enrollment. Semen samples were analyzed for total sperm count, sperm concentration, morphology, motility, ejaculate volume, total motile count, and total normal count. Dietary intake during the previous year was assessed by a validated food-frequency questionnaire. Fruit and vegetables were categorized as having high [Pesticide Residue Burden Score (PRBS) ≥4] or low-to-moderate (PRBS <4) pesticide residues on the basis of data from the USDA Pesticide Data Program. Linear regression models were used to analyze the associations of fruit and vegetable intake with semen variables and reproductive hormones while adjusting for potential confounding factors.

RESULTS

The total intake of fruit and vegetables was unrelated to semen quality. However, the intake of fruit and vegetables with low-to-moderate pesticide residues was associated with a higher total sperm count and sperm concentration, whereas the intake of fruit and vegetables with high pesticide residues was unrelated to semen quality. On average, men in the highest quartile of low-to-moderate-pesticide fruit and vegetable intake (≥2.8 servings/d) had a 169% (95% CI: 45%, 400%) higher total sperm count and a 173% (95% CI: 57%, 375%) higher sperm concentration than did men in the lowest quartile (<1.1 servings/d; P-trend = 0.003 and 0.0005, respectively). The intake of fruit and vegetables, regardless of pesticide-residue status, was not associated with reproductive hormone concentrations.

CONCLUSIONS

The consumption of fruit and vegetables with low-to-moderate pesticide residues was positively related to sperm counts in young men unselected by fertility status. This suggests that pesticide residues may modify the beneficial effects of fruit and vegetable intake on semen quality.

Male infertility: lifestyle factors and holistic, complementary, and alternative therapies

While we may be comfortable with an allopathic approach to male infertility, we are also responsible for knowledge about lifestyle modifications and holistic, complementary, and alternative therapies that are used by many of our patients. This paper provides an evidence-based review separating fact from fiction for several of these therapies. There is sufficient literature to support weight reduction by diet and exercise, smoking cessation, and alcohol moderation. Supplements that have demonstrated positive effects on male fertility on small randomized controlled trial (RCT) include aescin, coenzyme Q 10 , glutathione, Korean red ginseng, L-carnitine, nigella sativa, omega-3, selenium, a combination of zinc and folate, and the Menevit antioxidant. There is no support for the use of Vitamin C, Vitamin E, or saffron. The data for Chinese herbal medications, acupuncture, mind-body practice, scrotal cooling, and faith-based healing are sparse or inconclusive.

Intra- and inter-individual differences in human sperm DNA methylation

There is growing evidence that sperm DNA methylation is important in maintaining proper sperm health and function. Previous studies have associated sperm DNA methylation levels with sperm quality and function, however, little is known regarding the intra- and inter-individual variability in sperm methylation levels. This study characterizes this variation. Sperm epigenetic differences between successive semen samples from 12 patients were examined to identify the intra- and inter-individual differences globally across the genome, and in specifically defined genomic regions using the Illumina Infinium HumanMethylation450 BeadChips. Methylation analysis identified a bimodal distribution in the methylation levels that were non-uniformly distributed across the different genomic regions. The methylation levels were highly correlated in both the intra- and inter-individual comparisons. The intra-individual methylation levels were more highly correlated than the inter-individual comparison both globally and across the defined genomic regions, demonstrating that sperm DNA methylation levels are relatively stable between semen sample collections.

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.

Is thyroid hormones evaluation of clinical value in the work-up of males of infertile couples?

STUDY QUESTION

Is thyroid hormones (TH) evaluation of clinical value in the work-up of males of infertile couples?

STUDY ANSWER

Our results suggest that TH evaluation is not mandatory in the work-up of male infertility.

WHAT IS KNOWN ALREADY

A few previous studies performed on a limited series of subjects reported a negative impact of hyper- and hypo-thyroidism on semen volume, sperm concentration, progressive motility and normal morphology. No previous study has systematically evaluated associations between TH variation, semen parameters and ultrasound characteristics of the male genital tract.

STUDY DESIGN, SIZE AND DURATION

Cross-sectional analysis of a consecutive series of 172 subjects seeking medical care for couple infertility from September 2010 to November 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the entire cohort, 163 men (age 38.9 ± 8.0 years) free of genetic abnormalities were studied. All subjects underwent a complete andrological and physical examination, biochemical and hormonal assessment, scrotal and transrectal colour-Doppler ultrasound (CDUS) and semen analysis (including seminal interleukin 8 levels, sIL-8) evaluation within the same day.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the patients studied, 145 (88.9%) showed euthyroidism, 6 (3.7%) subclinical hyper- and 12 (7.4%) subclinical hypo-thyroidism. No subjects showed overt hyper- or hypo-thyroidism. At univariate analysis, no associations among thyroid-stimulating hormone (TSH) or TH levels and sperm parameters were observed. Conversely, we observed positive associations among free triiodothyronine (fT3) and free thyroxine (fT4) levels, ejaculate volume and seminal fructose levels. In a multivariate model, after adjusting for confounders such as age, body mass index, smoking habit, sexual abstinence, calculated free testosterone, prolactin and sIL-8 levels, only the associations found for fT3 levels were confirmed. When CDUS features were investigated, using the same multivariate model, we found positive associations between fT3 levels and seminal vesicles (SV) volume, both before and after ejaculation (adj. r = 0.354 and adj. r = 0.318, both P < 0.0001), as well as with SV emptying (ΔSV volume; adj. r = 0.346, P < 0.0001) and echo-texture inhomogeneity. In addition, after adjusting for confounders, negative associations between fT4 levels and epididymal body and tail diameters were found. No significant associations between TSH or TH levels and CDUS features of other organs of the male genital tract, including testis and prostate, were found. Finally, when the features of subjects with euthyroidism, subclinical hypo- and hyper-thyroidism were compared, no significant differences in seminal or hormonal parameters were found. Conversely, evaluating CDUS parameters, subjects with subclinical hyperthyroidism showed a higher difference between the SV longitudinal diameters measured before and after ejaculation when compared with that of subclinical hypothyroid men, even after adjusting for confounders (P < 0.007). All the other male genital tract CDUS characteristics did not differ among groups.

LIMITATIONS, REASONS FOR CAUTION

First, the number of patients investigated is relatively small and those with (subclinical) thyroid dysfunctions are an even smaller number; hence, it is therefore difficult to draw firm conclusions. Moreover, the present results are derived from patients consulting an Italian Andrology Clinic for couple infertility, and could have different characteristics from the male general population or from those males consulting general practitioners for reasons other than couple infertility. Finally, due to the cross-sectional nature of the study, neither a causality hypothesis nor mechanistic models can be inferred.

WIDER IMPLICATIONS OF THE FINDINGS

Although no associations between TH and sperm parameters were observed, present data support a positive effect of TH on SV size and a permissive role on the ejaculatory machinery, likely through an action on SV and epididymal contractility. This is the first study reporting such evidence. However, in contrast with the view that TH assessment is important for female fertility, our results do not support a systematic evaluation of thyroid function in males of infertile couples. How TH abnormalities impact male fertility needs to be addressed by further studies.

STUDY FUNDING/COMPETING INTERESTS

No funding was received for the study. None of the authors have any conflict of interest to declare.

Association of Fecundity With Changes in Adult Female Weight

OBJECTIVE

To evaluate whether weight change since age 18 years, current body mass index (BMI), and BMI at age 18 years are associated with fecundity.

METHODS

Our study included 1,950 women in the Nurses' Health Study 3 (2010-2014), a prospective cohort study, currently attempting pregnancy. Height, current weight, and weight at age 18 years were self-reported on the baseline questionnaire. Every 3-6 months thereafter, women reported the current duration of their pregnancy attempt. Multivariable-accelerated failure time models were used to estimate the time ratios and 95% confidence intervals (CIs).

RESULTS

For every 5-kg increase in body weight from age 18 years, current duration of pregnancy attempt increased by 5% (95% CI 3-7%). Compared with women who maintained weight, the adjusted median current duration was 0.5 months shorter in those who lost weight, 0.3 months longer for those who gained 4-9.9 kg and 10-19.9 kg, and 1.4 months longer for those who gained 20 kg or more (P trend ≤.001). The adjusted time ratio (95% CI) for a 5-kg/m increase in current BMI was 1.08 (1.04-1.12). After multivariable adjustment (including adjustment for current BMI), being underweight at age 18 years (BMI less than 18.5) was associated with a longer current duration of pregnancy attempt compared with normal-weight women (time ratio 1.25, 95% CI 1.07-1.47); however, being overweight or obese at age 18 years was not associated with fecundity.

CONCLUSION

Gaining weight in adulthood, being overweight or obese in adulthood, and being underweight at age 18 years were associated with a modest reduction in fecundity.

LEVEL OF EVIDENCE

II.

Relationship between Lipids Levels of Serum and Seminal Plasma and Semen Parameters in 631 Chinese Subfertile Men

Objective

This prospective study was designed to investigate the relationship between lipids levels in both serum and seminal plasma and semen parameters.

Methods

631 subfertile men were enrolled. Their obesity-associated markers were measured, and semen parameters were analyzed. Also, seminal plasma and serum TC, TG, HDL and LDL and serum FFA, FSH, LH, total testosterone (TT), estradiol (E2) and SHBG levels were detected.

Results

Seminal plasma and serum TG, TC and LDL levels were positively related to age. Serum TC, TG and LDL were positively related to obesity-associated markers (P < 0.001), while only seminal plasma TG was positively related to them (P < 0.05). For lipids levels in serum and seminal plasma, only TG level had slightly positive correlation between them (r = 0.081, P = 0.042). There was no significant correlation between serum lipids levels and semen parameters. However, seminal plasma TG, TC, LDL and HDL levels were negatively related to one or several semen parameters, including semen volume (SV), sperm concentration (SC), total sperm count (TSC), sperm motility, progressive motility (PR) and total normal-progressively motile sperm counts (TNPMS). Moreover, seminal plasma TG, TC, LDL and HDL levels in patients with oligospermatism, asthenospermia and teratozoospermia were higher than those with normal sperm concentration, motility or morphology. After adjusting age and serum LH, FSH, TT, E2 and SHBG levels, linear regression analysis showed that SV was still significantly correlated with seminal plasma LDL (P = 0.012), both of SC and TSC with seminal plasma HDL (P = 0.028 and 0.002), and both of PR and sperm motility with seminal plasma TC (P = 0.012 and 0.051).

Conclusion

The abnormal metabolism of lipids in male reproductive system may contribute to male factor infertility.

Association between air pollution and sperm quality: A systematic review and meta-analysis

Exposure to ambient air pollution has been clearly linked to adverse reproductive outcome and fecundation index, but its effects on male semen quality are still uncertain. In this study, we reviewed information from ten studies to get the qualitative evidence of the influence of the ambient air pollution on sperm quality and collected data from six of the ten studies to conduct meta-analysis. The original studies classified participants into different exposure levels and the highest and lowest expose levels were chosen as high expose and low expose groups, respectively. The random-effect model was used in the meta-analysis with the weight mean difference (WMD) as the measure indicator. The WMDs (95% confidence intervals, CIs) of sperm volume, sperm count, semen concentration, sperm progressive motility, total motility, and normal morphology were 0.09 (-0.04, 0.23), 0.46 (-4.47, 5.39), -8.21 (-20.38, 3.96), -7.76 (-16.26, 0.74), -7.61 (-16.97, 1.74) and -3.40 (-7.42, 0.62), respectively. In conclusion, although the differences are not statistically significant between the two groups, the overall trends and evidence from this review indicate the chronic exposure to ambient pollutants at high level may alter men sperm quality.

Spermatozoal cell death-inducing DNA fragmentation factor-α-like effector A (CIDEA) gene expression and DNA fragmentation in infertile men with metabolic syndrome and normal seminogram

BACKGROUND

This is the first study to investigate spermatozoal cell death-inducing DNA fragmentation factor-α-like effector A (CIDEA) gene expression and DNA fragmentations in the spermatozoa of men diagnosed with metabolic syndrome (MS) who have normal seminograms with unexplained infertility, and to correlate these parameters with seminal glucose concentration.

METHODS

This study included 120 participants: 75 male subjects with MS (38 fertile and 37 infertile), and a control group of 45 fertile males without MS. HOMA-IR, semen analysis, and biochemical measurement of seminal plasma insulin and glucose levels were carried out. Spermatozoal insulin gene and CIDEA gene expressions were performed by the RT-PCR method. The percentage of spermatozoal DNA fragmentation was also estimated.

RESULTS

The spermatozoal insulin and CIDEA gene expression, as well as the DNA fragmentation, were significantly higher in the infertile MS group than in the fertile MS group, and significantly higher in both the MS groups than in the control group. Seminal glucose concentration showed significant positive correlations with seminal insulin level, spermatozoa insulin, CIDEA gene expression, and DNA fragmentation. Moreover, there was a positive correlation between spermatozoa CIDEA gene expression and DNA fragmentation.

CONCLUSIONS

It can be concluded that MS may affect male fertility at the molecular level, through its possible inducing effect of spermatozoa CIDEA and insulin gene expression, DNA fragmentation, and increased seminal glucose.

Inverse U-shaped Association between Sleep Duration and Semen Quality: Longitudinal Observational Study (MARHCS) in Chongqing, China

STUDY OBJECTIVES

To investigate the association between sleep duration and semen parameters as well as reproductive hormone levels.

METHODS

We designed a cohort of male college students in Chongqing, China. A total of 796 subjects were recruited in 2013 and 656 (82.4%) were followed up in 2014. Each time, semen and peripheral blood samples were collected for semen quality and reproductive hormone measurement. Sleep duration was estimated by revised Munich Chronotype Questionnaire. In 2014, sleep quality was also measured by Pittsburgh Sleep Quality Index (PSQI).

RESULTS

There was a substantial inverse U-shaped association between sleep duration and two semen parameters (semen volume and total sperm number), with 7.0-7.5 h/day of sleep showing highest parameters. Either longer or shorter sleep was associated with decreased semen parameters in a dose-response manner (P = 0.002 and 0.001, respectively). Sleeping > 9.0 h was associated with a 21.5% (95% confidence interval 9.2, 32.2) reduction in semen volume and 39.4% (23.3, 52.1) reduction in total sperm number; sleeping ≤ 6.5 h was associated with 4.6% (-10.5, 22.3) and 25.7% (-1.2, 60.1) reduction. Increase of the two parameters was found in those who changed sleep duration toward 7.0-7.5 h/day from 2013 to 2014. The U-shaped association was independent from PSQI and was replicated in another dataset of 1,346 males. No association found between sleep duration and reproductive hormone.

CONCLUSIONS

Either restricted or excessive sleep may impair semen quality. Further research is needed to validate this finding.

[Gender Obesity Report--Influence of obesity on Reproduction and Pregnancy]

Obesity influences reproduction in men and women at all ages. The increasing prevalence of obesity is associated with rising numbers of reproductive disorders in both sexes. Obesity influences menstrual cycle and ovulation irregularities, increases pregnancy complications and complication rates in assisted reproductive technologies in women and in men obesity is associated with lower semen parameters. Weight loss through lifestyle changes or bariatric surgery has positive effects on hormonal parameters and fertility in both men and women.

Increased risk of incident chronic medical conditions in infertile men: analysis of United States claims data

OBJECTIVE

To determine the incidence of chronic medical conditions of men with infertility.

DESIGN

Retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

Subjects contained within the Truven Health MarketScan claims database from 2001 to 2009.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

The development of chronic medical conditions including hypertension, diabetes, hyperlipidemia, renal disease, pulmonary disease, liver disease, depression, peripheral vascular disease, cerebrovascular disease, heart disease, injury, alcohol abuse, drug abuse, anxiety disorders, and bipolar disorder.

RESULT(S)

In all, 13,027 men diagnosed with male factor infertility were identified with an additional 23,860 receiving only fertility testing. The average age was 33.1 years for men diagnosed with infertility and 32.8 years for men receiving testing alone. After adjusting for confounding factors, men diagnosed with male factor infertility had a higher risk of developing diabetes (hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.10-1.53), ischemic heart disease (HR 1.48, 95% CI 1.19-1.84), alcohol abuse (HR 1.48, 95% CI 1.07-2.05), and drug abuse (1.67, 95% CI 1.06-2.63) compared with men who only received infertility testing. Similar patterns were identified when comparing those with male factor infertility to vasectomized men. The association between male factor infertility and later health outcomes were strongest for men with longer follow-up.

CONCLUSION(S)

In this cohort of patients in a national insurance database, men diagnosed with male factor infertility had a significantly higher risk of adverse health outcomes in the years after an infertility evaluation. These findings suggest the overall importance of men's reproductive health and warrant additional investigation to understand the association and identify interventions to improve outcomes for these patients.

Costs of Foraging Predispose Animals to Obesity-Related Mortality when Food Is Constantly Abundant

Obesity is an important medical problem affecting humans and animals in the developed world, but the evolutionary origins of the behaviours that cause obesity are poorly understood. The potential role of occasional gluts of food in determining fat-storage strategies for avoiding mortality have been overlooked, even though animals experienced such conditions in the recent evolutionary past and may follow the same strategies in the modern environment. Humans, domestic, and captive animals in the developed world are exposed to a surplus of calorie-rich food, conditions characterised as ‘constant-glut’. Here, we use a mathematical model to demonstrate that obesity-related mortality from poor health in a constant-glut environment should equal the average mortality rate in the ‘pre-modern’ environment when predation risk was more closely linked with foraging. It should therefore not be surprising that animals exposed to abundant food often over-eat to the point of ill-health. Our work suggests that individuals tend to defend a given excessive level of reserves because this level was adaptive when gluts were short-lived. The model predicts that mortality rate in constant-glut conditions can increase as the assumed health cost of being overweight decreases, meaning that any adaptation that reduced such health costs would have counter-intuitively led to an increase in mortality in the modern environment. Taken together, these results imply that efforts to reduce the incidence of obesity that are focussed on altering individual behaviour are likely to be ineffective because modern, constant-glut conditions trigger previously adaptive behavioural responses.

Obesity and reproduction: a committee opinion

The purpose of this ASRM Practice Committee report is to provide clinicians with principles and strategies for the evaluation and treatment of couples with infertility associated with obesity. This revised document replaces the Practice Committee document titled, "Obesity and reproduction: an educational bulletin," last published in 2008 (Fertil Steril 2008;90:S21-9).

Testicular function in a birth cohort of young men

STUDY QUESTION

By investigating a birth cohort with a high ongoing participation rate to derive an unbiased population, what are the parameters and influences upon testicular function for a population not selected with regard to fertility?

SUMMARY ANSWER

While varicocele, cryptorchidism and obesity may impact on human testicular function, most common drug exposures and the presence of epididymal cysts appear to have no or minimal adverse impact.

WHAT IS KNOWN ALREADY

The majority of previous attempts to develop valid reference populations for spermatogenesis have relied on potentially biased sources such as recruits from infertility clinics, self-selected volunteer sperm donors for research or artificial insemination or once-fertile men seeking vasectomy. It is well known that studies requiring semen analysis have low recruitment rates which consequently question their validity. However, there has been some concern that a surprisingly high proportion of young men may have semen variables that do not meet all the WHO reference range criteria for fertile men, with some studies reporting that up to one half of participants have not meet the reference range for fertile men. Reported median sperm concentrations have ranged from 40 to 60 million sperm/ml.

STUDY DESIGN, SIZE AND DURATION

The Western Australian Pregnancy Cohort (Raine) was established in 1989. At 20-22 years of age, members of the cohort were contacted to attend for a general follow-up, with 753 participating out of the 913 contactable men. Of these, 423 men (56% of participants in the 20-22 years cohort study, 46% of contactable men) participated in a testicular function study. Of the 423 men, 404 had a testicular ultrasound, 365 provided at least one semen sample, 287 provided a second semen sample and 384 provided a blood sample.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Testicular ultrasound examinations were performed at King Edward Memorial Hospital, Subiaco, Perth, for testicular volume and presence of epididymal cysts and varicoceles. Semen samples were provided and analysed by standard semen assessment and a sperm chromatin structural assay (SCSA) at Fertility Specialists of Western Australia, Claremont, Perth. Serum blood samples were provided at the University of Western Australia, Crawley, Perth and were analysed for serum luteinizing hormone (LH), follicular stimulating hormone (FSH), inhibin B, testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), estradiol, estrone and the primary metabolites of DHT: 5α-androstane-3α,17β-diol (3α-diol) and 5-α androstane-3-β-17-beta-diol (3β-diol). Serum steroids were measured by liquid chromatography, mass spectrometry and LH, FSH and inhibin B were measured by ELISA assays.

MAIN RESULTS AND THE ROLE OF CHANCE

Cryptorchidism was associated with a significant reduction in testicular (P = 0.047) and semen (P = 0.027) volume, sperm concentration (P = 0.007) and sperm output (P = 0.003). Varicocele was associated with smaller testis volume (P < 0.001), lower sperm concentration (P = 0.012) and total sperm output (P = 0.030) and lower serum inhibin B levels (P = 0.046). Smoking, alcohol intake, herniorrhaphy, an epididymal cyst, medication and illicit drugs were not associated with any significant semen variables, testicular volume or circulating reproductive hormones. BMI had a significantly negative correlation with semen volume (r = -0.12, P = 0.048), sperm output (r = -0.13, P = 0.02), serum LH (r = -0.16, P = 0.002), inhibin B (r = -0.16, P < 0.001), testosterone (r = -0.23, P < 0.001) and DHT (r = -0.22, P < 0.001) and a positive correlation with 3αD (r = 0.13, P = 0.041) and DHEA (r = 0.11, P = 0.03). Second semen samples compared with the first semen samples in the 287 participants who provided two samples, with no significant bias by Bland-Altman analysis. Testis volume was significantly correlated positively with sperm concentration (r = 0.25, P < 0.001) and sperm output (r = 0.29, P < 0.001) and inhibin B (r = 0.42, P < 0.001), and negatively correlated with serum LH (r = -0.24, P < 0.001) and FSH (r = -0.32, P < 0.001). SCSA was inversely correlated with sperm motility (r = -0.20, P < 0.001) and morphology (r = -0.16, P = 0.005). WHO semen reference criteria were all met by only 52 men (14.4%). Some criteria were not met at first analysis in 15-20% of men, including semen volume (<1.5 ml, 14.8%), total sperm output (<39 million, 18.9%), sperm concentration (<15 million/ml, 17.5%), progressive motility (<32%, 14.4%) and morphologically normal sperm (<4%, 26.4%), while all five WHO criteria were not met in four participants (1.1%).

LIMITATIONS AND REASONS FOR CAUTION

This was a large cohort study; however, potential for recruitment bias still exists. Men who did not participate in the testicular evaluation study (n = 282) did not differ from those who did (n = 423) with regard to age, weight, BMI, smoking or circulating reproductive hormones (LH, FSH, inhibin B, T, DHT, E2, E1, DHEA, 3α-diol, 3β-diol), but were significantly shorter (178 versus 180 cm, P = 0.008) and had lower alcohol consumption (P = 0.019) than those who did participate.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrated the feasibility of establishing a birth cohort to provide a relatively unbiased insight into population-representative sperm output and function and of investigating its determinants from common exposures. While varicocele, cryptorchidism and obesity may impact on human testicular function, most common drug exposures and the presence of epididymal cysts appear to have little adverse impact, and this study suggests that discrepancies from the WHO reference ranges are expected, due to its derivation from non-population-representative fertile populations.

Invited Commentary: The Association Between Marijuana Use and Male Reproductive Health

Approximately 15% of all couples are unable to conceive after a year and are labeled infertile. In recent years, increasing attention has been given to lifestyle factors that may impact fertility. In the United States, it is estimated that there are more than 17 million current users of marijuana with 4.6 million using marijuana almost daily. Although common, to date, little data exist on the impact of marijuana use on male fertility. In the current issue of the Journal, Gundersen et al. (Am J Epidemiol. 2015;182(6):473-481) provide data examining the relationship between marijuana use and semen quality from young men recruited out of the general Danish population. Men who reported daily marijuana use displayed significant lower sperm concentration and sperm counts compared with nonusers, while testosterone levels were higher. The current report provides important information for patients and providers regarding the negative association of marijuana use on semen quality. Although the benefit of marijuana cessation on recovery is uncertain, further study on the impact of marijuana use on male reproductive health is warranted as more states explore marijuana legalization.

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.

Developing Federal Clinical Care Recommendations for Men

U.S. men experience substantial sexual and reproductive health needs across the life span. A significant barrier for providers in serving men in family planning, primary care, and sexually transmitted disease clinics has been the lack of standards for men's sexual and reproductive health care. The goal of this synthesis paper is to describe the development of clinical recommendations for the delivery of family planning services for men that were developed and published by CDC and the U.S. Office of Population Affairs. This paper is intended to describe the process used from 2011 to 2014 to develop the recommendations for the delivery of comprehensive reproductive healthcare services to men, and the rationale underpinning them.

Direct effects of leptin and adiponectin on peripheral reproductive tissues: a critical review

Obesity is a risk factor for infertility and adverse reproductive outcomes. Adipose tissue is an important endocrine gland that secretes a host of endocrine factors, called adipokines, which modulate diverse physiologic processes including appetite, metabolism, cardiovascular function, immunity and reproduction. Altered adipokine expression in obese individuals has been implicated in the pathogenesis of a host of health disorders including diabetes and cardiovascular disease. It remains unclear whether adipokines play a significant role in the pathogenesis of adverse reproductive outcomes in obese individuals and, if so, whether the adipokines are acting directly or indirectly on the peripheral reproductive tissues. Many groups have demonstrated that receptors for the adipokines leptin and adiponectin are expressed in peripheral reproductive tissues and that these adipokines are likely, therefore, to exert direct effects on these tissues. Many groups have tested for direct effects of leptin and adiponectin on reproductive tissues including the testis, ovary, uterus, placenta and egg/embryo. The hypothesis that decreased fertility potential or adverse reproductive outcomes may result, at least in part, from defects in adipokine signaling within reproductive tissues has also been tested. Here, we present a critical analysis of published studies with respect to two adipokines, leptin and adiponectin, for which significant data have been generated. Our evaluation reveals significant inconsistencies and methodological limitations regarding the direct effects of these adipokines on peripheral reproductive tissues. We also observe a pervasive failure to account for in vivo data that challenge observations made in vitro. Overall, while leptin and adiponectin may directly modulate peripheral reproductive tissues, existing data suggest that these effects are minor and non-essential to human or mouse reproductive function. Current evidence suggests that direct effects of leptin or adiponectin on peripheral reproductive tissues are unlikely to factor significantly in the adverse reproductive outcomes observed in obese individuals.

Lifestyles Associated With Human Semen Quality: Results From MARHCS Cohort Study in Chongqing, China

Decline of semen quality in past decades is suggested to be potentially associated with environmental and sociopsychobehavioral factors, but data from population-based cohort studies is limited. The male reproductive health in Chongqing College students (MARHCS) study was established in June 2013 as a perspective cohort study that recruited voluntary male healthy college students from 3 universities in Chongqing. The primary objectives of the MARHCS study are to investigate the associations of male reproductive health in young adults with sociopsychobehavioral factors, as well as changes of environmental exposure due to the relocation from rural campus (in University Town) to metro-campus (in central downtown). A 93-item questionnaire was used to collect sociopsychobehavioral information in manner of interviewer-interviewing, and blood, urine and semen samples were collected at the same time. The study was initiated with 796 healthy young men screened from 872 participants, with a median age of 20. About 81.8% of this population met the WHO 2010 criteria on semen quality given to the 6 routine parameters. Decreases of 12.7%, 19.8%, and 17.0%, and decreases of 7.7%, 17.6%, and 14.7% in total sperm count and sperm concentration, respectively, were found to be associated with the tertiles of accumulated smoking amount. Fried food consumption (1-2  times/wk or ≥3  times/wk vs nonconsumers) was found to be associated with decreased total sperm count (10.2% or 24.5%) and sperm concentration (13.7% or 17.2%), respectively. Coffee consumption was found to be associated with increased progressive and nonprogressive motility of 8.9% or 15.4% for subjects consuming 1-2  cups/wk or ≥3  cups/wk of coffee, respectively. Cola consumption appeared an association with decreased semen volume at 4.1% or 12.5% for 1-2  bottles/wk or ≥3  bottles/wk. A cohort to investigate the effects of environmental/sociopsychobehavioral factors act on semen quality was successfully set up. We found smoking, coffee/cola/fried foods consumption to be significantly associated with semen quality from the baseline investigation.

Obesity and reproductive function: a review of the evidence

PURPOSE OF REVIEW

Over the last decade, the evidence linking obesity to impaired reproductive function has grown. In this article, we review this evidence and discuss the underlying pathophysiology.

RECENT FINDINGS

Obese women are less likely than normal-weight women to achieve pregnancy. Female obesity adversely affects reproductive function through alterations in the hypothalamic-pituitary-ovarian axis, oocyte quality, and endometrial receptivity. It is unclear which mechanism contributes the most to subfecundity, and it is likely a cumulative process. Emerging data highlight the contribution of male obesity to impaired reproductive function and that couple obesity has synergistic adverse effects. Once pregnant, obese women are at higher risk for adverse pregnancy outcomes. Weight loss improves reproductive potential in obese patients. As obese women surpass 35 years of age, age may be more important than body mass index in determining reproductive potential.

SUMMARY

Obstetrician gynecologists need to be aware of the negative impact of obesity on reproductive function so that they appropriately counsel their patients. Further work is needed to clarify the underlying pathophysiology responsible for adverse effects of obesity on reproduction so that novel treatment approaches may be developed.

Body Mass Index Is Associated with Impaired Semen Characteristics and Reduced Levels of Anti-Müllerian Hormone across a Wide Weight Range

There is still controversy as to how body mass index (BMI) affects male reproduction. We investigated how BMI is associated with semen quality and reproductive hormones in 166 men, including 38 severely obese men. Standard semen analysis and sperm DNA integrity analysis were performed, and blood samples were analysed for reproductive hormones. Adjusted for age and time of abstinence, BMI was negatively associated with sperm concentration (B = -0.088, P = 0.009), total sperm count (B = -0.223, P = 0.001), progressive sperm motility (B = -0.675, P = 0.007), normal sperm morphology (B = -0.078, P = 0.001), and percentage of vital spermatozoa (B = -0.006, P = 0.027). A negative relationship was observed between BMI and total testosterone (B = -0.378, P < 0.001), sex hormone binding globulin (B = -0.572, P < 0.001), inhibin B (B = -3.120, P < 0.001) and anti-Müllerian hormone (AMH) (B = -0.009, P < 0.001). Our findings suggest that high BMI is negatively associated with semen characteristics and serum levels of AMH.

How does obesity affect fertility in men - and what are the treatment options?

Adiposity is associated with reduced fertility in men. The aetiology is multifactorial, with obese men at greater risk of suffering from impaired spermatogenesis, reduced circulating testosterone levels, erectile dysfunction and poor libido. The diagnosis and treatment of reduced fertility observed in obese men therefore requires insight into the underlying pathology, which has hormonal, mechanical and psychosocial aspects. This article summarises the current epidemiological, experimental and clinical trial evidence from the perspective of a practicing clinician. The following conclusions and recommendations can be drawn: Obesity is associated with low serum testosterone concentrations, but treatment with exogenous testosterone is likely to adversely impact on fertility. It is important to discuss this with men prior to initiation of testosterone therapy. Obesity adversely affects sperm concentration and may affect sperm quality. However, whether or not weight loss will correct these factors remain to be established. Oestrogen receptor modulators (and aromatase inhibitors) are unlicensed in the treatment for male hypogonadism and/or infertility. These treatments should hence be considered experimental approach until ongoing clinical trials report their outcomes.

Infertility etiologies are genetically and clinically linked with other diseases in single meta-diseases

The present review aims to ascertain whether different infertility etiologies share particular genes and/or molecular pathways with other pathologies and are associated with distinct and particular risks of later-life morbidity and mortality. In order to reach this aim, we use two different sources of information: (1) a public web server named DiseaseConnect ( http://disease-connect.org ) focused on the analysis of common genes and molecular mechanisms shared by diseases by integrating comprehensive omics and literature data; and (2) a literature search directed to find clinical comorbid relationships of infertility etiologies with only those diseases appearing after infertility is manifested. This literature search is performed because DiseaseConnect web server does not discriminate between pathologies emerging before, concomitantly or after infertility is manifested. Data show that different infertility etiologies not only share particular genes and/or molecular pathways with other pathologies but they have distinct clinical relationships with other diseases appearing after infertility is manifested. In particular, (1) testicular and high-grade prostate cancer in male infertility; (2) non-fatal stroke and endometrial cancer, and likely non-fatal coronary heart disease and ovarian cancer in polycystic ovary syndrome; (3) osteoporosis, psychosexual dysfunction, mood disorders and dementia in premature ovarian failure; (4) breast and ovarian cancer in carriers of BRCA1/2 mutations in diminished ovarian reserve; (5) clear cell and endometrioid histologic subtypes of invasive ovarian cancer, and likely low-grade serous invasive ovarian cancer, melanoma and non-Hodgkin lymphoma in endometriosis; and (6) endometrial and ovarian cancer in idiopathic infertility. The present data endorse the principle that the occurrence of a disease (in our case infertility) is non-random in the population and suggest that different infertility etiologies are genetically and clinically linked with other diseases in single meta-diseases. This finding opens new insights for clinicians and reproductive biologists to treat infertility problems using a phenomic approach instead of considering infertility as an isolated and exclusive disease of the reproductive system/hypothalamic-pituitary-gonadal axis. In agreement with a previous validation analysis of the utility of DiseaseConnect web server, the present study does not show a univocal correspondence between common gene expression and clinical comorbid relationship. Further work is needed to untangle the potential genetic, epigenetic and phenotypic relationships that may be present among different infertility etiologies, morbid conditions and physical/cognitive traits.

Exploration of the association between obesity and semen quality in a 7630 male population

This study aimed to explore the association between body mass index (BMI), other anthropometric indexes and semen quality in a general male population in Taiwan. In this cross-sectional cohort study, the study cohort consisted of 7941 healthy male individuals aged 18 years or older who participated in a standard medical screening program run by a private firm from January 2008 to May 2013. Semen parameters including sperm concentration (SC), total sperm motility (TSM), progressive motility (PRM), and normal sperm morphology (NSM) were recorded. Anthropometric indexes including BMI, waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and body fat percentage were measured. A total of 7630 men were enrolled for the final analysis, of whom 68.5% had a normal weight distribution and 31.4% were overweight or obese. Total sperm motility, progressive motility, normal sperm morphology and sperm concentration showed a statistically linear decline with increasing age (p < 0.001, p < 0.001, p < 0.001 and p = 0.004). Sperm concentration showed a significantly negatively linear association with BMI (p = 0.005), and normal sperm morphology showed an inverse association with BMI and waist-to-height ratio (p < 0.001 and p = 0.004). The prevalence of abnormal total sperm motility, progressive motility, normal sperm morphology and sperm concentration increased with increasing age (p = 0.011, p < 0.001, p < 0.001 and p = 0.002). Lower normal sperm morphology and sperm concentration were associated with increasing body adiposity (p<0.05). No relationship between obesity and sperm motility was identified.

Physical activity, fatness, educational level and snuff consumption as determinants of semen quality: findings of the ActiART study

In this study, the association between physical activity and other potential determinants, objectively measured by accelerometry, was examined. Sixty-two men attending an infertility clinic participated in the study. Obese men (body mass index ≥ 30) and those with a waist circumference 102 cm or more had lower semen volume than the other men (P < 0.05). Higher values in sperm parameters were observed in participants who completed university studies and those who did not consume snuff, compared with the other participants (P < 0.05). Finally, men who spent an average number of 10 min-bouts of moderate-to-vigorous physical activity had significantly better semen quality than those who engaged in low or high numbers of bouts of activity (P < 0.05). No associations were found for sedentary or moderate-to-vigorous physical activity time when it was not sustained over 10 min, i.e. not in bouts. Men who have average levels of physical activity over sustained periods of 10 min are likely to have better semen quality than men who engage in low or high levels of such activity. Similarly, high levels of total and central adiposity, low educational level and snuff consumption are negatively related to semen quality.

Relationship between physical occupational exposures and health on semen quality: data from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study

OBJECTIVE

To study the relationship among occupation, health, and semen quality in a cohort of men attempting to conceive.

DESIGN

Observational prospective cohort.

SETTING

Not applicable.

PATIENT(S)

A total of 501 couples discontinuing contraception were followed for 1 year while trying to conceive; 473 men (94%) provided one semen sample, and 80% provided a second sample.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Semen data obtained through at-home semen collection with next-day analysis/quantification.

RESULT(S)

In all, complete data were available for 456 men, with a mean age of 31.8 years. Work-related heavy exertion was consistently associated with lower semen concentration and total sperm count. Thirteen percent of men who reported heavy exertion displayed oligospermia, compared with 6% who did not report workplace exertion. Shift work, night work, vibration, noise, heat, and prolonged sitting were not associated with semen quality. Men with high blood pressure had significantly lower strict morphology scores compared with normotensive men (17% vs. 21%). In contrast, hyperlipidemia, diabetes, and composite of total comorbidities were not associated with semen quality. The number of medications a man was taking as a proxy of health status was associated with semen quality. There was a negative association between number of medications and sperm count.

CONCLUSION(S)

A negative relationship among occupational exertion, hypertension, and the number of medications with semen quality was identified. As these are potentially modifiable factors, further research should determine whether treatment or cessation may improve male fecundity.

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.

Metabolic syndrome-associated sperm alterations in an experimental rabbit model: relation with metabolic profile, testis and epididymis gene expression and effect of tamoxifen treatment

The influence of metabolic syndrome (MetS) on sperm quality and function is debated. Using a well-established high fat diet (HFD) rabbit model resembling human MetS, including development of hypogonadism, we demonstrate that HFD decreased sperm motility, morphology and acrosome reaction in response to progesterone and increased sperm cholesterol content. All the above parameters were associated with most MetS features, its severity and plasma testosterone (T) at univariate analysis. After T adjustment, sperm morphology and motility retained a significant association, respectively, with mean arterial pressure and circulating cholesterol levels. MetS modified the expression of inflammatory and tissue remodelling genes in the testis and of aquaporins in the epididymis. In a multivariate analysis, sperm morphology resulted associated with testis expression of fibronectin and collagen type 1 genes, whereas motility with epididymis aquaporin 1 gene. Administration of tamoxifen, used in the treatment of idiopathic male infertility, to HFD rabbits partially restored motility, but further decreased morphology and increased spontaneous acrosome reaction, without restoring responsiveness to progesterone. Overall our results indicate that development of MetS produces detrimental effects on sperm quality and functionality by inducing metabolic disorders leading to alterations in testis and epididymis functions and evidence a role of hypertension as a new determinant of abnormal sperm morphology, in line with a previous human study from our group.

Current smoking is associated with lower seminal vesicles and ejaculate volume, despite higher testosterone levels, in male subjects of infertile couples

STUDY QUESTION

What is the impact of smoking behaviour on seminal, hormonal and male genital tract ultrasound parameters in subjects seeking medical care for couple infertility?

STUDY ANSWER

In males of infertile couples, current smokers (CS), when compared with non-smokers, show lower ejaculate and ultrasound-derived seminal vesicles (SV) volume, despite higher testosterone levels.

WHAT IS KNOWN ALREADY

Data on the effects of smoking on male fertility are conflicting. A correlation between smoking and reduced semen parameters has been reported, however, with a high heterogeneity among studies. An association between smoking behaviour and higher testosterone levels in men has been described in several, but not all, the previous studies. No study has systematically evaluated the impact of smoking on the male genital tract ultrasound characteristics.

STUDY DESIGN, SIZE AND DURATION

Retrospective cross-sectional analysis of a consecutive series of 426 subjects seeking medical care for couple infertility from January 2010 to July 2013.

PARTICIPANTS/MATERIALS, SETTING, METHODS

From the entire cohort, 394 men (age 36.0 ± 8.0 years) free of genetic abnormalities were selected. All subjects underwent a complete andrological and physical examination, biochemical and hormonal assessment, scrotal and transrectal colour-Doppler ultrasound and semen analysis (including seminal interleukin-8 levels, sIL-8) within the same day.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the patients evaluated, 229 were never smokers (NS), 56 past smokers (PS) and 109 CS. When CS were compared with the rest of the sample (non-smokers, NS + PS), in a multivariate model (analysis of covariance, ANCOVA) adjusted for age, lifestyle (including alcohol, cannabis and physical activity), BMI and sex hormone-binding globulin, significantly higher androgen (total testosterone, P = 0.001; calculated free testosterone, P < 0.005) and lower FSH (P < 0.05) levels were observed in CS. However, when total testosterone was also included in the multivariate model as a further covariate, the difference in FSH levels was not confirmed. In a similar model, a lower ejaculate volume (P < 0.01) and a higher prevalence of normal sperm morphology (P < 0.02) were also detected in CS in comparison with the rest of the sample. However, when total testosterone was also included in the multivariate model as a further covariate, only the difference in ejaculate volume between CS and non-smokers was confirmed (-0.61 ± 0.23 ml, P < 0.01). Finally, CS showed lower total SV volume, before and after ejaculation, even after adjusting for confounders (P = 0.02 and <0.01, respectively). Similar results were observed when the reported number of cigarettes smoked or the number of pack-years was considered separately.

LIMITATIONS, REASONS FOR CAUTION

The present results are derived from patients consulting an Andrology Clinic for couple infertility, who could have different characteristics from the general male population or males consulting general practitioners for reasons other than couple infertility. In addition, we did not have a true control group composed of age-matched, apparently healthy, fertile men, and therefore true normative data of sonographic parameters cannot be inferred. Due to the cross-sectional nature of our study, neither a causality hypothesis nor mechanistic models can be drawn. Finally, this is a retrospective study, and further prospective studies are required.

WIDER IMPLICATIONS OF THE FINDINGS

We report an apparent paradox in CS: lower SV volume despite higher testosterone levels. Our data suggest that smoking may negatively affect SV volume in an independent manner, as the difference between CS and non-smokers retained significance after adjusting for confounders including testosterone. This is the first study reporting such ultrasound evidence. How this new smoking-related alteration, along with low semen volume, impacts male fertility needs to be addressed by further studies.

STUDY FUNDING/COMPETING INTERESTS

No funding was received for the study. None of the authors have any conflict of interest to declare.

Relationship between semen production and medical comorbidity

OBJECTIVE

To study the relationship between semen quality and current health status in a cohort of men evaluated for infertility.

DESIGN

Cross-sectional study.

SETTING

Fertility clinic.

PATIENT(S)

Nine thousand three hundred eighty-seven men evaluated for infertility between 1994 and 2011.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Charlson comorbidity index, medical diagnoses by organ system.

RESULT(S)

At the time of evaluation, 9,387 men with a mean age of 38 years had semen data available. Of these men, 44% had at least one medical diagnosis unrelated to infertility. When stratifying the cohort by the Charlson comorbidity index (CCI), differences in all measured semen parameters were identified. Men with a higher CCI had lower semen volume, concentration, motility, total sperm count, and morphology scores. In addition, men with diseases of the endocrine, circulatory, genitourinary, and skin diseases all showed significantly higher rates of semen abnormalities. Upon closer examination of diseases of the circulatory system, men with hypertensive disease, peripheral vascular and cerebrovascular disease, and nonischemic heart disease all displayed higher rates of semen abnormalities.

CONCLUSION(S)

The current report identified a relationship between medical comorbidites and male semen production. Although genetics help guide a man's sperm production, his current condition and health play an important role.