NASHVILLE, Tenn. — Weight loss surgery did more than help severely obese teen boys drop a few pounds.

In preliminary research presented at the American Heart Association’s Arteriosclerosis, Thrombosis and Vascular Biology/Peripheral Vascular Disease 2016 Scientific Sessions, weight loss surgery also increased their “good” cholesterol levels.

“We already knew that weight loss surgery improves weight and cholesterol numbers,” said Amy S. Shah, M.D., lead author of the study and assistant professor of pediatrics at the Cincinnati Children’s Hospital in Ohio.

“This new research shows that there are actually changes in the way high density lipoprotein (HDL) functions in adolescents, which may lead to a reduction in long-term cardiovascular risk.”

In the study, 10 teenage boys averaging 367 pounds underwent vertical sleeve gastrectomy to reduce the size of the stomach. One year after surgery, the teens:

  • Increased levels of the so-called good cholesterol by 23 percent.
  • Lost an average 111 pounds.
  • Reduced their body mass index by 32 percent. Body mass index is a scientific way to evaluate body weight.

In addition to measuring HDL levels, the researchers performed several tests to assess whether surgery had an impact on HDL function. Among their findings:

  • Cholesterol efflux, the ability of HDL to remove cholesterol from artery walls so it can be sent to the liver and removed from the body, increased 12 percent.
  • HDL oxidation potential, a measure of how easily HDL generates oxidants or free radicals that can trigger unwanted inflammation, decreased 30 percent.
  • HDL became more anti-inflammatory, with a 25 percent decrease on the HDL inflammatory index.

“Despite remaining obese, these young men showed improved metabolic health measured by HDL function after surgery,” Shah said.

The preliminary study is limited by small numbers and having no female participants.