Background: Even though obesity surgery normalizes circulating testosterone concentrations in males with obesity-associated secondary hypogonadism, its impact on spermatogenesis remains controversial. We aimed to evaluate sperm characteristics in obese men after bariatric surgery as well as changes in reproductive hormones.
Methods: Twenty severely obese men (body mass index (BMI) ≥ 35 kg/m2) were evaluated before and 2 years after bariatric surgery. The serum was assayed for insulin, leptin, kisspeptin, and inhibin B, among other hormones. Homeostasis model assessment of insulin resistance (HOMA-IR) was estimated. We used World Health Organization reference values for sperm analysis.
Results: After surgery, serum total testosterone, calculated free testosterone, inhibin B, and kisspeptin increased, whereas fasting insulin, HOMA-IR, and leptin concentrations decreased. Despite these improvements, sperm volume showed a small decrease after surgery, while the rest of sperm characteristics remained mostly unchanged. Abnormal sperm concentration persisted in 60% of the patients.
Conclusions: Sperm characteristics may not improve after bariatric surgery despite the beneficial changes of reproductive hormones.
Keywords: Bariatric surgery; Kisspeptin; Leptin; Male infertility; Obesity; Semen analysis.