The Impact Of Male's Overweight/Obese On IVF Treatment Outcomes And The Possible Mechanism

Overweight and obesity are ongoing worldwide epidemics, and their effects on reproductive health have been widely studied in women. Overweight or obese women exhibit increased times to pregnancy they are at an increased risk of early and recurrent miscarriage. In comparison, few studies have focused on the impact of the male's weight on assisted reproductive technology(ART) outcomes. Numerous studies have examined the impacts of overweight and obesity on semen parameters with conflicting results. In particular, the impact of the male's weight on embryonic development during IVF has been rarely studied.Telomeres are highly repeated hexameric(TTAGGG) nucleotide sequences at the ends of chromosomes. One study found that the shortening of long telomeres in sperm can help sustain the critical telomere length required for normal cleavage post-fertilization. Our most recent study also demonstrated that sperm telomere length(STL) is positively associated with early embryonic quality. Obesity is often accompanied by oxidative stress and inflammation. Oxidative stress is an important contributing factor to telomere attrition. A recent study found that BMI was positively correlated with reactive oxygen species(ROS) production in semen. However, little is known about the effects of overweight and obesity on STL or these statuses relationships regarding IVF treatment outcomes. Objective:To evaluated the effects of men's body mass index(BMI) on STL and clinical treatment outcomes during in vitro fertilization(IVF). Methods:Patient selection Our sample consisted of 306 males of abnormal weight(>28 kg/m2) and 345 age-matched males of normal weight(20-25 kg/m2). All patients were undergoing treatment at our reproductive medical center for first fresh IVF cycles. We used a well-established and well-validated quantitative real-time Polymerase Chain Reaction(PCR) technique to measure the mean STLs and analyzed the associations between STL and IVF outcomes using Pearson's correlation or Multivariable regression model, as appropriate. Results:1.Couples in which the male had a BMI over 28 kg/m2 exhibited significantly lower fertilization rates(P=0.002), high-quality embryo rates(P=0. 044) and clinical pregnancy rates(P=0. 038) than their normal weight counterparts.2.A multivariate logistic regression analysis revealed that men with BMIs over 28 kg/m2 were associated with lower clinical pregnancy rates(odds ratio 0.75 [95% CI=0.61 – 0. 88]; P<0. 01) after adjusting for female BMI, female age, basic follicle-stimulating hormone(FSH) level, male age, number of embryos transferred and sperm count.3.The mean STL in the abnormal BMI group was also significantly shorter than that of the normal weight group(P<0. 001).4.Individuals with an abnormal BMI showed higher ROS content(P<0.01) and sperm DNA fragmentation rates(P<0. 01) than individuals with normal BMIs.5.Mitochondrial activity was also lower in the normal BMI group than the abnormal BMI group. Conclusions:This report is the first to show that STL is shorter in overweight/obese men, possibly accounting for the poor IVF treatment outcomes in these patients.