Impact of Bariatric Surgery on Male Sex Hormones and Sperm Quality: a Systematic Review and Meta-Analysis

This systematic review and meta-analysis aims to establish the effects of bariatric surgery on male sex hormones, sperm parameters, and sexual function. We searched MEDLINE, EMBASE, Web of Science, and Scopus from database inception through June 2018. Articles were eligible for inclusion if they examined the effect of bariatric surgery on male sex hormones and sperm parameters in patients with obesity. Primary outcomes of interest were sex hormones and sperm quality. Secondary outcome was sexual function (International Index of Erectile Function (IIEF) score). Pooled estimates were calculated using random effects meta-analysis. A total of 28 cohort studies with 1022 patients were identified from 3896 potentially relevant citations. Both free and calculated testosterone levels were significantly increased after bariatric surgery (mean difference (MD) -7.47nM, 95% CI -8.62 to -6.31, p<0.001 and MD -0.05nM, 95% CI -0.07 to -0.02, p<0.001, respectively). Consistent with the increase in testosterone, LH, FSH, and SHBG levels were also significantly increased after surgery. In contrast, free and total estradiol and prolactin levels were significantly decreased after bariatric surgery. From studies that reported the IIEF score, bariatric surgery led to a significant increase in erectile function after surgery (MD -0.46, 95% CI -0.89 to -0.02, p=0.04). However, bariatric surgery did not affect sperm quality, DHEA, androstenedione, and inhibin B levels. Sustained weight-loss induced by bariatric surgery had a significant effect on increasing male sex hormones and decreasing female sex hormones in male patients with obesity. However, sperm quality and function were not improved after surgery.