Teen bone loss found after gastric bypass

Teens who undergo gastric bypass weight-loss surgery can expect to have a decline in bone mass, just as adults do, according to a new study.

Two years after the surgery, the bone mineral content of the 61 obese teens studied had declined, on average, by 7.4 percent, said Dr. Anne-Marie Kaulfers, an assistant professor of pediatrics at the University of South Alabama.

"At the moment, I do not think there is cause for alarm," Kaulfers said of the study findings. That's because the teens, who averaged 17 years old, still had bone mass within the normal range, she said. They had started with above-average bone mass for their age and gender.

The findings were reported online Monday in the journal Pediatrics.

Kaulfers and her colleagues decided to study the teens because a loss of bone mineral content during adolescence, when they should be approaching peak bone mass, could potentially compromise future bone health.

Studies of adults have found that their bone mass also declines after the surgery.

Kaulfers did the study while at Children's Hospital Medical Center in Cincinnati. Some participants were part of the Teen-Longitudinal Assessment of Bariatric Surgery Consortium supported by the National Institutes of Health.

All of the teens, 10 boys and 51 girls, had gastric bypass, a procedure in which the stomach is reduced from the size of a football to that of a golf ball.

Though what happens beyond two years is unknown, Kaulfers said that the bone loss appears to be offset by the benefits of the surgery, such as reducing the likelihood developing diabetes.

But teens who have the surgery need to be closely monitored, she cautioned.

The bone loss after weight-loss surgery may be due to the weight loss itself, she said, or it could stem from other factors, such as hormonal changes.