Kahn Barbara E, Brannigan Robert E
Division of Male Reproductive Surgery and Men's Health, Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
Curr Opin Urol. 2017 Sep;27(5):441-445. doi: 10.1097/MOU.0000000000000417.
The prevalence of obesity has risen steadily for the past 35 years and presently affects more than a third of the US population. A concurrent decline in semen parameters has been described, and a growing body of literature suggests that obesity contributes to the male infertility. The purpose of this review is to examine the effects of obesity on male fertility, the mechanisms by which impaired reproductive health arise, and the outcomes of treatment.
Obesity alters the hypothalamic-pituitary-gonadal axis both centrally and peripherally, resulting in hypogonadotropic, hyperestrogenic hypogonadism. Adipose tissue-derived factors, like leptin and adipokines, regulate testosterone production and inflammation, respectively. Increased systemic inflammation results in increased reactive oxygen species and sperm DNA fragmentation. Increased testicular temperature because of body habitus and inactivity impairs spermatogenesis. The degree to which obesity affects hormone levels, semen parameters, sperm DNA integrity, and pregnancy rates is variable, which may be the result of other comorbid conditions. Treatment in the form of weight loss has also had inconsistent results.
Multiple interdependent mechanisms contribute to the detrimental effect of obesity on male fertility. Large, randomized control trials are needed to better characterize the therapeutic benefits of weight loss to restore male reproductive potential.
在过去35年里，肥胖症的患病率稳步上升，目前影响着超过三分之一的美国人口。同时有文献描述精液参数有所下降，并且越来越多的文献表明肥胖会导致男性不育。本综述的目的是研究肥胖对男性生育能力的影响、生殖健康受损产生的机制以及治疗结果。
肥胖会在中枢和外周改变下丘脑-垂体-性腺轴，导致促性腺激素分泌不足、高雌激素性性腺功能减退。脂肪组织衍生因子，如瘦素和脂肪因子，分别调节睾酮的产生和炎症反应。全身炎症反应增加会导致活性氧增加和精子DNA碎片化。由于体型和缺乏运动导致的睾丸温度升高会损害精子发生。肥胖对激素水平、精液参数、精子DNA完整性和妊娠率的影响程度各不相同，这可能是其他合并症导致的结果。减肥形式的治疗效果也不一致。
多种相互依存的机制导致肥胖对男性生育能力产生有害影响。需要进行大型随机对照试验，以更好地描述减肥对恢复男性生殖潜力的治疗益处。
