Our meta-analysis was performed to compare bariatric surgery on semen parameters and reproductive hormones. This study reported that the semen volume had significantly difference between the postperative operation group and baseline group (p=0.0006). Contrary, HaithamEl Bardis et al found that the semen volume had no significant difference between the two groups (p>0.05). Eisenberg et al, found that the semen volume had significant relation with BMI (p=0.005). Additionally, they found no significant difference between the BMI and semen concentration (p=0.564). Similarly, Samavat et al conducted a prospective study included the bariatric surgery group and non-bariatric group. They found the changes of BMI was associated with in sperm volume (r=0.618, p<0.05) with statically significant. MacDonald et al performed a cross-sectional study recruit 514 men suggested that the sperm volume (r=0.02, p>0.05).
Additionally, they found that the sperm concentration had a negative correlation with bariatric surgery without statically significantly (r=-0.05, p>0.05). The meta-analysis showed that the semen concentration had no difference between the preoperative and postoperative group (p=0.86). Haithamm et al demonstarted that no significant difference between the two pre and postoperative group.
Hammiche et al involved 450 men of subfertile couples with subfertitly demonstrated that the BMI was an independent factor to affect the sperm motility (r=-0.62, p<0.05). Kort et al conducted a study involving 520 healthy men reported that the BMI of male partners had a negative relation with motile sperm count (p<0.05). Consistently, Richard et al also found that man with bartriatic surgery had no relation with sperm motility 12-month post-surgery (p=0.60). Similarly, Macdonald et al performed a meta-analysis included 31 studies found that the no correlation between the semen parameters and BMI . The present study also found that no correlation between the sperm motility and barbiac surgery (p=1.00). However, Samavat et al conducted a study included 23 patients found that the the number and progressive or total sperm motility was in increase with statistically significant. Additionally, they found that after the age-adjusted multivariate analysis indicated that the BMI changes were related with sperm morphology. These results were not accordance with ours. MacDonald et al also found that the BMI was not correlate with sperm motility with adjusted RR (0.96 95%CI: 0.38-2.47 p>0.05). This is consistent with ours. Several studies which were included larger than 500 men indicated that the BMI had no significant difference with sperm parameters (p>0.05). Reis et al performed a prospectively study concluding that the bariatric surgery could not change the sperm motility, which was consistently with our meta-analysis.
Our study illustrated that the bartiarc surgery had no relation with the semen morphology (P=0.85). Jensen et al recurit 1,558 volunteers using the strict morphological criteria found no association between BMI (>25 kg/m2) and sperm morphology . Buchwald et al conducted a meta-analysis almost 70% of patients had an abnormal semen analysis, the sperm concentration, morphology and total motility, 63% and 33%, respectively.
Our study also found that the testosterone level was higher in postoperative group than baseline with a significant difference (WMD:4.63, 95%CI 2.65 to 6.61, P<0.05). Similarly, Linn et al performed a cohort study recruit 43 participants (with BMI>33kg/m2) with a weight loss programe indicating that a significant increase in testosterone (p = 0.02).
The hormonal profile in obese men assessed in this study was characterized by abnormalities in sex hormones, and weight loss improved with the change of the hormone levels, however, they were not normalized. In our meta-analysis, the hormones were also pooled directly without transformation. However, the men were severely obese at baseline and may stay obese or overweight after the weight loss surgery. However, postoperative changes in sex hormone levels cannot be contributed to reduction of adipose tissue. Contrary to this, several reports have highlighted negative consequences with worsening of semen parameters after bariatric surgery, indicating that nutrient malabsorption may lead to long-term effects on male fertility.
Sermondate et al conducted a meta-analysis involving 13077 men from the attending fertility clinic and general population found that BMI is assocaite with increased prevalence oligozoospermia or azoospermia the odds ratio (95% conﬁdence interval) for azoospermia was 1.15 (0.93–1.43) or oligozoospermia for underweight, 1.11 (1.01–1.21) for overweight, 1.28 (1.06–1.55) for obese and 2.04 (1.59–2.62) for morbidly obese men. Haitham El Bardisi et al found that the sperm quality could be better after the loss of weight especially in ogolisperm man.
Bartatic surgery included gastric bypass and aliminatary reconstruction which induce substantial weight loss. The decline of body weight had association of the level of reproductive hormone concentrations. The hormone level may associate with the spermatogenesis process. This may result the change of the semen quality. MacDonald et al performed a meta-analysis contained 31 studies found that the BMI was not associated with estradiol and BMI, which was coincidental with our study. However, Pasquali et al did find statistically significant positive relationships between BMI and estradiol. Such a relationship is might due to increased peripheral conversion of androgen to estrogen associated with the surplus adipose tissue present at man with higher BMI. Our study showed that no significant difference was found with bariatric surgery. However, Jensen et al. (2004) believed that a statistically significant negative relation between BMI and both sperm concentration
21.6% (95% CI 4.0%-39.4%).
Our study had several limitations. Firstly, the small number of patients in our meta-analysis. Secondly, the included studies were non-RCts. Thirdly, we could not exclude selection bias existing the three studies. The included studies lack of FSH, LH, sex-hormonebinding-Globulin (SHBG) to pool and explore the association between bariatric surgery and hormones.