Background: Male sexual dysfunction is common in obesity with complex underlying mechanisms. Testosterone replacement has often been initiated in clinical practice in the presence of sexual dysfunction and male obesity-associated secondary hypogonadism. The benefits to sexual functioning, however, are not well documented. The aims of the study were to investigate the relationship between sexual function and hypogonadism in severe obesity and to understand the impact of bariatric surgery (BS)-induced weight loss.
Methods: Sexual function was assessed using the European Male Ageing Study-Sexual Function Questionnaire in 26 men (mean age 49.4±9.8, mean body mass index (BMI) 47.6±7.0) before and in 14 of them (mean BMI 33.2±5.3) reassessed between 6 to 12 months after BS. Participants were divided into two groups (low and high) based on the median values of the overall sexual function (OSF) domain of the questionnaire. Fasting morning blood samples were obtained for androgen profile.
Results: Erectile dysfunction was present in 73% of men before surgery. Fifty seven percent of men had a testosterone level of less than 9.5 nmol/l. Testosterone levels, however, were not significantly different between men with low (median 8.4) and high (median 9.4) OSF scores (P=0.598). OSF (P=0.003) and other domains of sexual function including erectile function (P=0.04) and sexual function-related distress (P=0.004) improved after BS. Serum testosterone increased (P=0.003) from median 9.4 nmol/l at baseline to (6.512.1) to 16.1 nmol/l (11.617.3) after BS. Similarly, sex hormone-binding globulin improved (P=0.002) from median 31.8 nmol/l (21.639.3) to 50.2 nmol/l (38.868.2). Changes in sexual function scores before and after BS did not correlate with changes in serum testosterone.
Discussion: Male sexual function improves after BS though this appears to be independent of changes in testosterone. Other factors like nerve and vascular function may have a more significant role. For symptoms of sexual dysfunction alone in the context of severe obesity, testosterone replacement may not be beneficial.