Weight loss is a major contributor to improved sexual function after bariatric surgery

The relative contribution of anthropometric, hormonal, and metabolic changes after bariatric surgery (BS) on sexual function (SF) in severely obese subjects is not well established. Prospective observational case series study of 39 men undergoing BS. SF was assessed by means of the international index of erectile function (IIEF) before and at 1 year after surgery. At the same time points, anthropometric (body mass index, waist circumference), hormonal (testosterone, sex hormone binding globulin, estradiol, gonadotropins, inhibin B, prolactin, leptin), and metabolic parameters (insulin sensitivity, C-reactive protein, lipid profile, hemoglobin A1c, presence of hypertension or sleep apnea) were assessed. BS was associated with marked weight loss (77.18 % excess weight loss), improved IIEF score (baseline: 54.85 +/- A 16.59, 1 year: 61.21 +/- A 14.10; p < 0.01), gonadal function (testosterone: baseline 256.36 +/- A 120.98, 1 year: 508.01 +/- A 161.90; p < 0.001), and improved metabolic profile. However, on multivariate regression analysis whereas changes in body mass index (beta: -0.677, p = 0.001), and baseline IIEF score (beta: -0.397, p = 0.023), were independent predictors of the changes in the IIEF score at 1 year after surgery, changes in hormonal and metabolic factors were not. Variables in the model accounted for 66 % of the postsurgical variation in the IIEF score. Similar results were found when the different IIEF-sexual domains were evaluated, except for intercourse satisfaction for which no independent predictor was identified. Weight loss's beneficial effects on SF occurring after BS are beyond the parallel improvement in gonadal and metabolic profiles.