Does an increase in adipose tissue ‘weight’ affect male fertility? A systematic review and meta‐analysis based on semen analysis performed using the WHO 2010 criteria

Abstract

IntroductionObesity negatively impact on the metabolism of sex hormones, leading to reduced testosterone serum levels. However, how the obesity could negatively impact on the overall gonadal function, particularly on male fertility, remained unclear so far.ObjectiveTo systematically review evidences regarding the influence of body weight excess on the sperm production.MethodsA meta‐analysis was conducted, searching all prospective and retrospective observational studies reporting male subjects older than 18 years old, with body weight excess from overweight to severe obesity were considered. Only studies using the V edition of the World Health Organization (WHO) manual for semen analysis interpretation were considered. No specific interventions were considered. Search was focused on studies comparing overweight/obese to normal weight subjects.ResultsTwenty‐eight studies were considered. Total sperm count and sperm progressive motility were significantly lower in overweight compared to normal weight subjects. Meta‐regression analyses demonstrated that patients’ age impacted on sperm parameters. Similarly, obese men showed lower sperm concentration, total sperm number, progressive and total motilities, and normal morphology lower than normal weight subjects. Reduced sperm concentration in obese men was influenced by age, smoking habit, varicocele, and total testosterone serum levels at meta‐regression analyses.ConclusionsThe male potential fertility is reduced in subjects with increased body weight, compared to normal weight men. The higher was the increased body weight, the worst was the sperm quantity/quality. This result comprehensively included obesity among non‐communicable risk factor for male infertility, shedding new lights on the negative impact of increased body weight on overall gonadal function.

Increased serum creatinine associated with testicular microlithiasis in adult Japanese men: A retrospective cohort study

“…A lack of exercise-one of the causes of obesity-is known to affect spermatogenesis. 25 In addition, overweight or obesity is a risk factor for lowered semen parameters and abnormal reproductive hormone levels. 26,27 We hypothesize that being overweight affects testicular function, which might induce the development of TM.…”

“…However, as in European or American countries, the prevalence of obesity in Japan is increasing. A lack of exercise—one of the causes of obesity—is known to affect spermatogenesis 25 . In addition, overweight or obesity is a risk factor for lowered semen parameters and abnormal reproductive hormone levels 26,27 .…”

Advanced Paternal Age in Focus: Unraveling Its Influence on Assisted Reproductive Technology Outcomes

“…While the ramifications of increased maternal age on fertility and pregnancy outcomes are well-documented, the implications of advancing paternal age are less clear and present unique challenges [7,8]. It is important to note that the intersection of advancing age and obesity introduces additional complications, such as hormonal changes, oxidative stress, and temperature stress, which are particularly exacerbated by the common occurrence of varicocele in older males, further impairing fertility [9][10][11]. The present work navigates through these complexities, exploring the decline in testicular function and semen quality as well as the potential genetic and epigenetic shifts that accompany advancing paternal age.…”

Effect of antioxidants on semen parameters in men with oligo‐astheno‐teratozoospermia: a network meta‐analysis

“…[2][3][4][5][6][7][8][9] In addition to iatrogenic, genito-urinary, and systemic disorders, several environmental and lifestyle-related factors can unbalance the relationship between ROS generation and antioxidant defenses, with an overall unfavorable impact on sperm biology. [10][11][12] Indeed, spermatozoa are uniquely sensitive to the oxidative damage for many reasons, ranging from the low availability of antioxidant enzymes within a virtually absent cytoplasm, to the composition of the plasma membrane rich in polyunsaturated fatty acids, which are easily subject to lipid peroxidation. 10,13,14 In addition, there is the intrinsic ability of the sperm cell to generate ROS through complex molecular pathways directly or indirectly related to mitochondrial dysfunction.…”