By Mary Elizabeth Dallas
FRIDAY, Jan. 6, 2017 (HealthDay News) -- Weight-loss surgery helps severely obese teens keep extra pounds off long-term, new research confirms.
However, the authors of the two new studies also found that some young people may need additional surgery to manage complications associated with their rapid post-surgery weight loss.
Some young patients may also develop nutritional deficiencies after their procedure, the researchers said.
These are the first long-term follow-up studies on teens that undergo weight-loss surgery, the researchers noted.
The findings "clearly document long-term benefits of adolescent bariatric [weight-loss] treatment, but also highlight several nutritional risks," said lead author Dr. Thomas Inge of Cincinnati Children's Hospital Medical Center.
"Now it is important to focus on delivery of the substantial health advantages of surgery while minimizing these risks," Inge said in a news release from The Lancet Diabetes & Endocrinology. The findings were published in the journal on Jan. 5.
According to background information in the study, some 4.6 million children and teens in the United States are severely obese -- defined as roughly 100 pounds or more overweight.
Severe obesity leads to poor health and quality of life, which is why many of these teens are offered the option to undergo weight-loss surgery, the researchers explained.
In one of the new studies, researchers followed 58 young Americans between 13 and 21 years old who had one type of weight-loss surgery known as gastric bypass.
Eight years after surgery, these patients had an average weight reduction of 30 percent. Nearly two-thirds of the teens remained obese, though not severely so. The study showed that only one patient dropped down to a normal weight.
Among the teens who had weight-loss surgery, the number of those with diabetes, high cholesterol or high blood pressure dropped significantly. Along with these health benefits, however, 78 percent of the teens developed low levels of vitamin D, and 16 percent were deficient in vitamin B12. Mild anemia was diagnosed in 46 percent of these young people.
These nutritional deficiencies could stem from the fact that the teens were simply eating less, or they may be absorbing nutrients less well, the researchers explained.
They noted, however, that the health benefits of weight-loss surgery far surpass these manageable nutrient issues.
For the second study, researchers tracked 81 obese teens and adults in Sweden who had weight-loss surgery and compared them to 80 teens who didn't have the procedure. They found those who had the surgery had maintained an average 28 percent weight reduction after five years, while those who didn't have surgery gained more weight.
But among the teens who had the surgery, 25 percent did require additional surgery to manage complications from the procedure or the rapid weight loss that followed, such as bowel blockage and gallstones.
This meant more time in hospitals: Teens who had weight-loss surgery were hospitalized for an average of 6.5 days, while those who didn't have surgery were in the hospital for 1.5 days on average.
Teens who'd undergone weight-loss surgeries also had an average of five extra visits to an outpatient clinic compared to those who hadn't had the operation, the study found.
The researchers noted the overall cost to treat teens who underwent weight-loss surgery was roughly equivalent to the control group. And one in every four of the young people in the control group eventually did go on to have weight-loss surgery as an adult.
It's not clear which type of weight-loss surgery works best for teens, Inge said. "Since there are currently two effective bariatric procedures, namely gastric bypass and vertical sleeve gastrectomy, we are currently examining the outcomes of both procedures to determine what is best for adolescents," he said.
Despite some dramatic weight loss, many of the teens who had weight-loss surgery were still obese (but not severely obese) afterwards.
According to the study authors, this suggests positive lifestyle changes -- such as following a healthy diet and getting regular exercise -- are still important.
Dr. Mitchell Roslin is chief of obesity surgery at Lenox Hill Hospital in New York City. He reviewed the findings and said they highlight the benefit of surgery for severely obese young patients.
He said that according to prior research, "once obesity reaches this level in teens, it adversely affects future success more than drug addiction, alcohol or poverty."
Based on that, Roslin believes that "lasting weight loss [through weight-loss surgery] should be considered 'salvage therapy' and pursued to rescue more teens."
While the side effects noted in the studies can happen, this only shows "there is no perfect solution to what is truly a chronic and very detrimental condition," Roslin said. "The reality of this situation has to be accepted and access to surgery more easily provided."