Why T Counts Are Falling

Type 2 diabetes can lead to low testosterone. So can obesity. This is especially alarming for teen boys.

illustration of male teen playing video games and eating junk food.

Nearly 20 years ago, a University at Buffalo researcher named Paresh Dandona made a vital discovery: One-third of men with Type 2 diabetes have low testosterone counts. Over the past two decades, further studies by Dandona and his research team on the connection between the two afflictions—as well as the connection between obesity and low testosterone levels—have led to a multitude of key findings on the prevention, management and even reversal of diabetes. Perhaps most striking is what they’ve learned about obesity and low testosterone in teenage boys.

Findings galore

Dandona, a SUNY Distinguished Professor and former chief of endocrinology at UB, discovered a link between low testosterone (hypogonadism) and Type 2 diabetes in 2004. In 2010, he and his research group determined that one-fourth of obese males without diabetes also have hypogonadism, revealing that diabetes and obesity are at the root of low testosterone—and, relatedly, impotence. They went on to demonstrate in 2016 that diabetic patients with hypogonadism have additional insulin resistance that lowers with testosterone treatment. Remarkably, in a 2020 study, they were able to reverse diabetes in one-third of study participants using testosterone therapy.

obesity up arrow testosterone down arrow.

Obese teens and low T

In 2013, Dandona and his group studied the connection between obesity and hypogonadism in teens and young adults between the ages of 14 and 20, finding that testosterone levels are 50% lower in obese boys. Then, in a 2022 study, they found that 75% of morbidly obese boys had low testosterone. Notably, over a period of two years when the teens lost weight after bariatric surgery, their testosterone normalized. Low T levels then recurred in those who gained weight again.

“It really is an obesity problem, which has to be tackled,” said Dandona. “Because the majority of my patients are middle-aged and past their fertile years, the impact of low testosterone isn’t as significant. However, when you look at the younger age group, many of whom I expect to be impotent or infertile, the implications are profound.”

testosterone molecule.

A powerhouse program

Dandona, who recently received a Lifetime Achievement Award from the Androgen Society for his immense contributions to the field, came to Buffalo in 1991 when UB was looking for a head of endocrinology, and proceeded to construct a world-class program from scratch.

UB’s fellowship program is now one of the largest in the country, having graduated 90 fellows who are now spread all over the United States, and the clinical center is one of the largest in the state. “Our standards of care in diabetes are probably the best in the world,” said Dandona, “with no major amputations since 1997 and no end stage kidney failure if the patient comes to us with a reasonable kidney function.”