The impact of male overweight on semen quality and outcome of assisted reproduction

discussed by Thomsen et al. 3 These discrepancies are possibly due to the multifactorial nature of fertilization or the sperm selection process and need to be addressed in larger, controlled multi-center studies. Age is well-associated with the decline in testosterone levels, and to a lesser degree paternal fertility potential. In this study, men were relatively young (mean 32.8 ± 5.1 years), thus reflecting normal reproductive age. However, it is plausible that in younger males obesity may have a less dramatic negative impact on endocrine and fertility parameters than in older men. This may partly explain some of the inconsistent results in the literature cited by Thomsen et al. 3 Indeed, the mean male age in Keltz et al. 3 discuss that others reported no negative effect of increased BMI on ICSI outcome. However, although not reported as a predictor for fertilization, implantation, pregnancy or miscarriage, a high BMI negatively impacted on ICSI success. 6 The entire cohort in this study (n = 250) had a mean age of 38.4 ± 9.3 years. 6 Considering that the subjects in the Thomsen study were significantly (P = 0.0001) younger that in other studies, it is plausible that obesity may impact more on male reproductive health with increasing age. Many of the cited studies appear to suggest a less dramatic impact on ART outcome for ICSI than in IVF. Although no study has looked at this specifically, many of them seem to suggest ICSI superior in paternal obesity. This too requires detailed investigation, which may also suggest novel mechanisms for obesity-related fertility problems. However, the key question arising is why are these studies continuously inconsistent? The answer could lie in an age-related impact of obesity, different degrees of underlying metabolic changes or other potential confounders. REFERENCES 1 MacDonald AA, Herbison GP, Showell M, Farquhar CM. The impact of body mass index on semen parameters and reproductive hormones in human males: a systematic review with meta‑analysis. The impact of male overweight on semen quality and outcome of assisted reproduction. Overweight men: clinical pregnancy after ART is decreased in IVF but not in ICSI cycles. A Jr, et al. Food intake and social habits in male patients and its relationship to intracytoplasmic sperm injection outcomes. The impact of obesity on male reproductive health remains a contested topic as evidence is inconclusive and inconsistent. Even more debatable is the effect of male obesity in assisted reproduction. …