Bariatric surgery in men: effects on gonadal hormones, body composition, glucose, lipid and bone metabolism
E. Aarts1, B. van Wageningen1, S. Loves1, I. Janssen1, F. Berends1, F. Sweep2 & H. de Boer1
Background: Obesity-related, isolated hypogonadotropic hypogonadism (IHH) occurs in more then 40% of morbidly obese men.
Hypothesis: IHH and prolonged persistence of low testosterone levels after bariatric procedures may reduce the beneficial effects of surgery.
Objective: To evaluate the impact of IHH on the results of bariatric surgery.
Patients and methods: observational study with measurement of gonadal hormone levels, assessment of body composition and glucose, lipid and bone metabolism during the first year after bariatric surgery in 13 hypogonadal (free testosterone <225 pmol/l) and 11 age-matched eugonadal morbidly obese men (free testosterone >225 pmol/l).
Results: serum free testosterone rose gradually after bariatric surgery in eugonadal as well as in hypogonadal men. The increase in free testosterone was directly related to the amount of weight loss. Gonadal hormone status prior to surgery did not affect the 1-year outcome of bariatric surgery, but the type of surgery did. Gastric bypass induced a greater loss of fat, but also caused a greater loss of muscle and bone than gastric banding.
Conclusion: Bariatric surgery raised serum T levels, but the improvement was less in hypogonadal than in eugonadal men. Obesity-related IHH did not reduce the efficacy of bariatric surgery.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.