Objective: Obesity in adolescent males is associated with lowering of total and free testosterone concentrations. Weight loss may increase testosterone concentrations.
Design and Methods: We evaluated changes in sex hormones following bariatric surgery in 34 males (age range 14.6 – 19.8 years) with obesity. These participants were part of prospective multicenter study, Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS). Participants were followed for five years after surgery. Total testosterone, total estradiol, LH, FSH, SHBG, CRP, insulin and glucose were measured at baseline, six months and annually thereafter. Free testosterone, free estradiol and HOMA2-IR were calculated.
Results: Study participants lost one-third of their body weight after bariatric surgery, with maximum weight loss achieved at 24 months for most participants. Free testosterone increased from 0.17 nmol/L(95% CI: 0.13, 0.20) at baseline to 0.34 (95% CI: 0.30, 0.38) at two years and 0.27(95% CI: 0.23, 0.32) nmol/L at five years (p<0.001 for both) respectively. Total testosterone increased from 6.7 nmol/L (95% CI: 4.7, 8.8) at baseline to 17.6(95% CI: 15.3, 19.9) and 13.8(95% CI: 11.0, 16.5) nmol/L at two and five years(p<0.001). Prior to surgery 73% of the participants had subnormal free testosterone(<0.23 nmol/L). After two years and five years, only 20% and 33%, respectively, had subnormal free testosterone concentrations. Weight regain was related to a fall in free testosterone concentrations.
Conclusions: Bariatric surgery led to a robust increase in testosterone concentrations in adolescent males with severe obesity. Participants who regained weight had a decline in their testosterone concentrations.
Bariatric Surgery vs Lifestyle Intervention for Diabetes Treatment: 5-Year Outcomes From a Randomized Trial
