BACKGROUND The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to update the evidence on the association between BMI and sperm count through a systematic review with meta-analysis. METHODS A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n = 717 men) obtained from the Infertility Center of Bondy, France. Abstracts of relevant articles were examined and studies that could be included in this review were retrieved. Authors of relevant studies for the meta-analysis were contacted by email and asked to provide standardized data. RESULTS A total of 21 studies were included in the meta-analysis, resulting in a sample of 13 077 men from the general population and attending fertility clinics. Data were stratified according to the total sperm count as normozoospermia, oligozoospermia and azoospermia. Standardized weighted mean differences in sperm concentration did not differ significantly across BMI categories. There was a J-shaped relationship between BMI categories and risk of oligozoospermia or azoospermia. Compared with men of normal weight, the odds ratio (95% confidence interval) for oligozoospermia or azoospermia was 1.15 (0.93-1.43) for underweight, 1.11 (1.01-1.21) for overweight, 1.28 (1.06-1.55) for obese and 2.04 (1.59-2.62) for morbidly obese men. CONCLUSIONS Overweight and obesity were associated with an increased prevalence of azoospermia or oligozoospermia. The main limitation of this report is that studied populations varied, with men recruited from both the general population and infertile couples. Whether weight normalization could improve sperm parameters should be evaluated further.

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

Male obesity in reproductive-age men has nearly tripled in the past 30 y and coincides with an increase in male infertility worldwide. There is now emerging evidence that male obesity impacts negatively on male reproductive potential not only reducing sperm quality, but in particular altering the physical and molecular structure of germ cells in the testes and ultimately mature sperm. Recent data has shown that male obesity also impairs offspring metabolic and reproductive health suggesting that paternal health cues are transmitted to the next generation with the mediator mostly likely occurring via the sperm. Interestingly the molecular profile of germ cells in the testes and sperm from obese males is altered with changes to epigenetic modifiers. The increasing prevalence of male obesity calls for better public health awareness at the time of conception, with a better understanding of the molecular mechanism involved during spermatogenesis required along with the potential of interventions in reversing these deleterious effects. This review will focus on how male obesity affects fertility and sperm quality with a focus on proposed mechanisms and the potential reversibility of these adverse effects.

https://www.tandfonline.com/doi/pdf/10.4161/spmg.21362

Impact of obesity on male fertility, sperm function and molecular composition.

Spermatogenesis in humans and its affecting factors.

study question: What is the relationship between body size, physical activity and semen parameters among male partners of couples attempting to become pregnant? summaryanswer: Overweight and obesity are associated with a higher prevalence of low ejaculate volume, sperm concentration and total sperm count. what is known already: Higher BMI is associated with impaired semen parameters, while increasing waist circumference (WC) is also associated with impaired semen parameters in infertile men. study design, size, duration: Data from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study were utilized. The LIFE study is a population-based prospective cohort of 501 couples attempting to conceive in two geographic areas (Texas and Michigan, USA) recruited in 2005–2009. Couples were recruited from four counties in Michigan and 12 counties in Texas to ensure a range of environmental exposures and lifestyle characteristics. In person interviews were conducted to ascertain demographic, health and reproductive histories followed by anthropometric assessment. participants/materials,setting,methods: We categorized BMI (kg/m 2 )a s,25.0 (underweight and normal), 25.0 –29.9 (overweight) 30.0 –34.9 (obese, class I) and ≥35 (obese, class II) for analysis. Data were available for analysis in 468 men (93% participation), with a mean+ SD age of 31.8+ 4.8 years, BMI of 29.8+ 5.6 kg/m 2 and WC of 100.8+ 14.2 cm. The majority of the cohort (82%) was overweight or obese with 58% reporting physical activity ,1 time/week. The median sperm concentration for the men in the cohort was 60.2 M/ml with 8.6% having oligospermia (,15 M/ml). main results and the role of chance: When examining semen parameters, ejaculate volume showed a linear decline with increasing BMI and WC (P , 0.01). Similarly, the total sperm count showed a negative linear association with WC (P , 0.01). No significant relationship was seen between body size (i.e. BMI or WC) and semen concentration, motility, vitality, morphology or DNA fragmentation index. The percentage of men with abnormal volume, concentration and total sperm increased with increasing body size (P , 0.05). No relationship between physical activity and semen parameters was identified. limitations, reasons for caution: Our cohort was largely overweight and sedentary, which may result in limited external validity, i.e. generalizability. The lack of physical activity did preclude examination of exercise more frequently than once per week, thus our abilit yt o examine more active individuals is limited. wider implications of the findings: Body size (as measured by BMI or WC) is negatively associated with semen parameters with little influence of physical activity. Our findings are the first show ing ar elationship between WC and semen parameters in as ample of men without known infertility. Given the worldwide obesity epidemic, further study of the role of weight loss to improve semen parameters is warranted.

The relationship between male BMI and waist circumference on semen quality: data from the LIFE study

Obesity, male infertility, and the sperm epigenome.

Recent studies have underlined the impact of obesity on sperm parameters, but very few data are available on the effect of weight loss on male fertility. This article reports the case series of three male patients who underwent rapid and major weight loss following bariatric surgery and the consequences of this surgery on semen parameters and fertility. A severe worsening of semen parameters was observed during the months after bariatric surgery, including extreme oligoasthenoteratozoospermia, but azoospermia was not observed. This effect may hypothetically be the result of two opposite mechanisms: (i) the suppression of the deleterious effects of obesity; and (ii) the negative impact of both nutritional deficiencies and the release of toxic substances. Information about potential reproductive consequences of bariatric surgery should be given to patients and sperm cryopreservation before surgery proposed. However, for one case, the alterations of spermatogenesis were reversible 2 years after the surgical procedure. Finally, intracytoplasmic sperm injection with fresh spermatozoa after male bariatric surgery can be successful, as demonstrated here, where clinical pregnancies were obtained for two out of the three couples.

https://www.rbmojournal.com/article/S1472-6483(11)00600-6/pdf

Jérôme Pfeffer

Papers

Sperm parameters and male fertility after bariatric surgery: three case series.