Updated: Feb 15
Bariatric surgery can reverse low testosterone levels in teen males with obesity, according to a study by researchers led by University of Buffalo. According to the study investigators, this is the first major study to examine how weight loss after bariatric surgery affects testosterone in adolescent boys.
The finding is important because in addition to reducing inflammation and increasing insulin sensitivity, weight loss after bariatric surgery may also influence sexual and fertility functions. Results were featured in the paper, ‘High prevalence of subnormal testosterone in obese adolescent males: reversal with bariatric surgery’, published in the European Journal of Endocrinology.
Obesity in adolescent boys can often lead to hypogonadism, as shown by lower-than-normal testosterone concentrations, which may lead to sexual difficulties and reduced fertility.
"It is remarkable that testosterone levels more than doubled and in fact normalised in most adolescent boys who underwent bariatric surgery, and this was maintained up to five years," said study co-author, Dr Thomas Inge, Surgeon-in-Chief and Director of Adolescent Bariatric Surgery Program at Ann & Robert H. Lurie Children's Hospital of Chicago, and Professor of Surgery and Pediatrics at Northwestern University Feinberg School of Medicine. "This testosterone response was greater than that expected in adults undergoing these same operations and adds to the growing list of benefits of using bariatric surgery in teenagers with severe obesity."
The study involved 34 teen males with severe obesity who were enrolled in Teen-Longitudinal Assessment of Bariatric Surgery, a prospective, NIH funded observational study. These teens underwent bariatric surgery and were followed for five years. Prior to surgery, only 27 percent of participants had normal free testosterone levels. The researchers measured total testosterone, total estradiol, luteinizing hormone, follicle-stimulating hormone, sex hormone-binding globulin, C-reactive protein, insulin and glucose at baseline, six months and annually thereafter. Free testosterone, free estradiol and HOMA2-IR were calculated.
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 at baseline to 0.34 and 0.27nmol/L at two and five years (p<0.001 for both), respectively. Total testosterone increased from 6.7 at baseline to 17.6 and 13.8nmol/L at two and five years (p<0.001), respectively. Prior to surgery, 73% of the participants had subnormal free testosterone (<0.23nmol/L). After two and five years, only 20 and 33%, respectively, had subnormal free testosterone concentrations. Weight regain was related to a fall in free testosterone concentrations.
The study results, which was led by Dr Paresh Dandona's team in the Division of Endocrinology at the University of Buffalo, provides hope that adolescent males with severe obesity who undergo bariatric surgery may have a better outlook for future metabolic health and fertility.
"The rise in testosterone levels paired with improvement in insulin sensitivity after bariatric surgery point to benefits in improving glucose metabolism, fertility, lipid metabolism, bone mineralisation, and muscle mass," said Dr Ellen Kim, pediatric endocrinologist and Medical Director of the Interdisciplinary Weight Management Program at Lurie Children's, as well as Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine. “These changes can help decrease morbidity over the lifespan related to obesity-related complications.”