Popular weight loss surgery in teens weakens bones

“Childhood obesity is a major public health problem that has been increasing over the past 10 years,” said lead researcher Miriam A. Bredella, MD, professor of radiology at Harvard Medical School in Boston, Massachusetts, and vice president of the Department of Radiology at Massachusetts General Hospital in Boston. “Sleeve gastrectomy is the most common bariatric surgery procedure performed in children and adults.”

In a sleeve gastrectomy, approximately 75% of the stomach is removed to limit food intake and induce weight loss. The result is a typically round stomach that takes the shape of a tube or sleeve. The number of sleeve gastrectomy procedures performed on adolescents increased 100-fold from 2005 to 2014.

“In adults, bariatric surgery can have long-term effects on the bones, leading to an increased risk of fractures,” said Dr. Bredella. “We wanted to determine the effects of sleeve gastrectomy performed on adolescents during the crucial years when bone mass is building up.”

The study looked at 52 adolescents with moderate to severe obesity, 26 of whom underwent sleeve gastrectomy. The other 26 were in the control group. The mean age was 17.5 years and the mean body mass index (BMI) was 45. A BMI of 30 or higher is considered obese. Thirty-eight of the study participants were girls. Before and 12 months after sleeve gastrectomy (or no surgery), patients underwent quantitative CT of the lumbar spine to quantify volumetric bone mineral density. Quantitative CT is a highly accurate technique for detecting changes in volumetric bone mineral density after extreme weight loss.

Recent studies have shown that bone marrow fat responds to changes in nutrition and can serve as a biomarker for bone quality. Therefore, patients underwent MRI proton spectroscopy to quantify lumbar spine bone marrow fat.

One year after surgery, adolescents undergoing sleeve gastrectomy lost 34 (+/- 13) kg, or 75 (+/- 28) pounds, while there was no significant weight change in the control group. . Compared to controls, patients with sleeve gastrectomy had a significant increase in bone marrow fat and a decrease in bone density in the lumbar spine.

“Teenagers who underwent sleeve gastrectomy had bone loss and an increase in bone marrow fat, despite marked loss of body fat,” said Dr. Bredella. “While weight loss surgery is successful for weight loss and improvement of metabolic disorders, it has negative effects on the bones.”

Dr Bredella said the loss of bone density after sleeve gastrectomy was expected because greater loading strengthens the bones. In addition to a loss of bone density, other effects of weight loss surgery include a disruption of hormones and nutrients that are important for bone health.

“We need to identify mechanisms that will help prevent bone loss in these patients and to make adolescents with obesity more aware of bone health,” he said. “Adolescence is the critical time for bone buildup and any process that interferes with bone buildup during this time can have disastrous consequences later in life.”

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Co-authors are Vibha Singhal, MD, Nazanin Hazhir Karzar, MD, Abisayo Animashaun, BS, Amita Bose, BS and Madhusmita Misra, MD, MPH

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