Research Finds Weight Loss in Obese Boys Improves Testosterone Levels

ST. LOUIS – Obese adolescent boys who lose weight following bariatric surgery improve their testosterone levels, according to Saint Louis University School of Medicine and University of Buffalo researchers.

The study, “High Prevalence of Subnormal Testosterone in Obese Adolescent Males: Reversal with Bariatric Surgery,” published in the European Journal of Endocrinology.

Sandeep Dhindsa, M.D., a SLUCare endocrinologist and the director of SLU’s Division of Endocrinology, Diabetes and Metabolism, is first author on the paper. 

“Obese boys do not achieve sufficient testosterone levels at puberty and weight loss can theoretically improve testosterone,” Dhindsa said. “We checked the testosterone levels in obese boys who underwent bariatric surgery. Those who lost weight had increased testosterone levels. Those who regained weight had a lowering of testosterone again.”

In the study, researchers evaluated the changes in sex hormones following bariatric surgery in 34 male patients between the ages of 14-19. These participants were part of a long-term multi-center study, the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS).

Teen-LABS is the first large study to systematically document the outcome of metabolic bariatric surgery for treatment of adolescents with severe obesity in the United States.

The participants were followed for five years following surgery. Total testosterone, estradiol, luteinizing hormone, follicle stimulating hormone, sex hormone binding globulin, insulin and glucose were measured before surgery, six months’ post-operative and annually thereafter. The study showed that bariatric surgery, in addition to treating obesity and reversing Type 2 diabetes, reversed low testosterone levels.

“Males usually achieve their peak testosterone concentrations at puberty, followed by a gradual decline for the rest of their life. Adolescent males with obesity start off with a lower testosterone. We do not know the long-term effects on fertility and sexual function. Testosterone is also important for muscle and bone growth. Our study provides strong evidence that weight loss can restore normal testosterone concentrations in these boys,” Dhindsa said.

Prior to surgery, 73% of participants had subnormal free testosterone levels. Two years later, only 20% had subnormal free testosterone concentrations. Five years later, that percentage rose to 33% due to regained weight among some participants.

Common causes of low testosterone in adults are aging, obesity and diabetes. Male adults with obesity have lower testosterone levels than lean adults.

This work was supported by the National Institutes of Health (NIH), grant numbers UM1D072493 (University of Colorado) and UM1DK095710 (University of Cincinnati). Funding for the ancillary study was provided by the Divisions of Endocrinology of University of Buffalo and Saint Louis University.

The study’s senior author is Paresh Dandona, M.D., SUNY Distinguished Professor at the Jacobs School of Medicine and Biomedical Sciences at the University of Buffalo. 

Additional authors include Husam Ghanim, Ph.D., Division of Endocrinology, Diabetes and Metabolism, Jacobs School of Medicine and Biosciences, University of Buffalo; Todd Jenkins, Ph.D., Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center; Thomas H. Inge, M.D., Ph.D., University of Colorado Denver and Children’s Hospital Colorado; Carroll M. Harmon, M.D., Ph.D., Division of Pediatric Surgery, John R. Oishei Children’s Hospital and Jacobs School of Medicine and Biosciences, University of Buffalo; Amit Ghoshal, Ph.D., Quest Diagnostics, Nichols Institute; Zengru Wu, Ph.D., Endocrine Division, Quest Diagnostics, Nichols Institute; Michael J. McPhaul, M.D., Endocrine Division, Quest Diagnostics, Nichols Institute; and Farid Saad, DVM, Ph.D., Gulf Medical University, Research Department.

Dhindsa is a former fellow in the Division of Endocrinology, Diabetes and Metabolism in the Jacobs School at University of Buffalo. 

Saint Louis University School of Medicine

Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first medical degree west of the Mississippi River. The school educates physicians and biomedical scientists, conducts medical research, and provides health care on a local, national and international level. Research at the school seeks new cures and treatments in five key areas: cancer, liver disease, heart/lung disease, aging and brain disease, and infectious diseases.