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 Dandona, SUNY Distinguished Professor of medicine.

“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 percent of them had subnormal free testosterone levels, below .23 nanomoles per liter (nmol/L). Two years later, only 20 percent had subnormal free testosterone concentrations and five years later, that percentage rose to 33 percent 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 percent lower in obese versus normal boys, and in 2016, the group demonstrated that men with hypogonadism and Type 2 diabetes had 35 percent 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 percent of non-diabetic obese men and 33 percent 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, Diabetes and Metabolism in the Department of Medicine and by Saint Louis University.

Sandeep Dhindsa, MD, first author on the paper and formerly a trainee in the endocrinology, diabetes and metabolism fellowship, is now chief of endocrinology at Saint Louis University.

Other UB co-authors are:

• Husam A. Ghanim, PhD, research associate professor of medicine
• Carroll M. Harmon, MD, professor of surgery, John E. Fisher Chair in Pediatric Surgery, chief of the Division of Pediatric Surgery and director of the pediatric surgery fellowship program

Additional co-authors are from Saint Louis University, the University of Colorado and Quest Diagnostics at the Nichols Institute.