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Bariatric surgery reverses low testosterone in severely obese male teens

Female doctor measuring overweight boy in clinic.

A new UB study has found that bariatric surgery and weight loss led to normalization of testosterone levels in severely obese male teens.


Published February 8, 2022

headshot of Paresh Dandona.
“These boys, if they persist with obesity, will suffer with a lifetime of impotence and infertility. ”
Paresh Dandona, SUNY Distinguished Professor
Jacobs School of Medicine and Biomedical Sciences at UB

A new study led by UB researchers shows that bariatric surgery not only treats obesity and reverses Type 2 diabetes, it also reverses low testosterone levels in obese male teens.

The finding is important because of testosterone’s role in reducing inflammation and increasing insulin sensitivity, in addition to its sexual and fertility functions.

“We have shown that in severely obese teen males, bariatric surgery and weight loss led to normalization of testosterone concentrations,” says senior author Paresh Dandona, SUNY Distinguished Professor in the Jacobs School of Medicine and Biomedical Sciences at UB. “This is the first major study in obese adolescents examining the effect of bariatric surgery in this age group, leading to normalization of testosterone concentrations.”

The concept of low testosterone levels, known as hypogonadism, in males with Type 2 diabetes and obesity originated over a decade ago with Dandona, who sees patients at UBMD Internal Medicine.

“Considering that one-third of the American population is obese, prevention and treatment of hypogonadism remains a major task,” he explains. He notes that previous work by his team has demonstrated that testosterone replacement results in loss of adiposity and an equivalent buildup of muscle.

The current study involved 34 severely obese male teens who underwent bariatric surgery, and were followed for five years. Prior to surgery, 73% of them had subnormal free testosterone levels, below .23 nanomoles per liter (nmol/L). Two years later, only 20% had subnormal free testosterone concentrations and five years later, that percentage rose to 33% due to participants who regained some of the weight they had lost.

The study was part of the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS), the largest national study to examine the effects of bariatric surgery on adolescents.

“These boys, if they persist with obesity, will suffer with a lifetime of impotence and infertility,” Dandona says.

The discovery of this syndrome of hypogonadism in Type 2 diabetes was made by Dandona’s group at UB in 2004. In 2010, the group demonstrated that testosterone levels are 50% lower in obese versus normal boys, and in 2016, the group demonstrated that men with hypogonadism and Type 2 diabetes had 35% additional insulin resistance. Dandona adds that a previous study has also shown that obese boys have been shown to have smaller penises than boys who aren’t obese, an additional indication of compromised sexual function.

“Physicians should realize that 25% of non-diabetic obese men and 33% of Type 2 diabetics suffer from hypogonadism,” Dandona says. “The U.S. has nearly 35 million diabetics and over 100 million obese individuals. Every Type 2 diabetic, obese male should be tested for testosterone deficiency.”

The study was funded by the Division of Endocrinology in the Department of Medicine in the Jacobs School and by Saint Louis University.

Sandeep Dhindsa, first author on the paper and formerly a fellow in the Division of Endocrinology, Diabetes and Metabolism in the Jacobs School, is now chief of endocrinology at Saint Louis University. Other UB co-authors are Husam Ghanim of the Department of Medicine, and Carroll Harmon of the Department of Pediatrics and John R. Oishei Children’s Hospital. Additional co-authors are from Saint Louis University, the University of Colorado and Quest Diagnostics at the Nichols Institute.