Skeletal Effects of Sleeve Gastrectomy in Obese Adolescents

Two-year skeletal effects of sleeve gastrectomy in adolescents with obesity evaluated with quantitative CT and MR spectroscopy

Weight-loss surgery weakens bones in teens and young adults

According to a study published in Radiology , a journal of the Radiological Society of North America (RSNA), a common weight loss surgery for obese adolescents and young adults has harmful effects on bones.

“Childhood obesity is on the rise and weight-loss surgery is the most effective way to reduce weight and improve cardiometabolic comorbidities,” said the study’s principal investigator, Miriam A. Bredella, MD, professor of radiology at the School of Harvard Medicine in Boston, Massachusetts. , and vice president of Faculty Affairs and Clinical Operations, Department of Radiology, Massachusetts General Hospital in Boston. “This is the first study in adolescents and young adults that examined the long-term effects of sleeve gastrectomy, the most common type of weight-loss surgery, on bone strength and bone marrow fat.”

Sleeve gastrectomy removes approximately 75% to 80% of the stomach to restrict food intake and induce weight loss. It results in a typically round stomach that takes the shape of a tube or sleeve. The estimated number of sleeve gastrectomy procedures performed each year increased from more than 28,000 surgeries in 2011 to more than 122,000 in 2020, according to the American Society for Metabolic and Bariatric Surgery. Sleeve gastrectomy has surpassed gastric bypass as the leading weight loss operation.

For the study, participants ages 13 to 24 were enrolled from 2015 to 2020. Adolescents and young adults were moderately to severely obese. Young adults had a maximum body index (BMI) of 35 or more. A BMI of 30 or higher is considered obese. Adolescent participants were at 120% of the age- and sex-specific 95th percentile.

There were 54 participants, 25 who underwent sleeve gastrectomy and 29 who were in the control group. Forty-one study participants were women. The surgical group included participants with at least one obesity-related comorbidity, or a BMI of 40 or higher. The control group was obese but did not plan to undergo a sleeve gastrectomy, but received dietary and exercise advice.

Before and 24 months after sleeve gastrectomy, participants underwent a physical examination, blood tests, and quantitative computed tomography of the lumbar spine, to quantify volumetric bone mineral density and perform finite element analysis, a technique that can estimate bone strength. Quantitative CT is a high-precision technique for detecting changes in volumetric bone mineral density after extreme weight loss.

Studies have shown that bone marrow fat responds to changes in nutrition and may serve as a biomarker of bone quality. Therefore, patients underwent proton MR spectroscopy to quantify lumbar spine bone marrow fat.

Two years after surgery, BMI in adolescents and young adults decreased (-11.9, on average), while there was a slight increase in BMI in the control group (+1.5, on average). Compared with controls, sleeve gastrectomy patients had a significant increase in bone marrow fat and a decrease in bone density and strength estimates in the lumbar spine.

"We found that bone strength was lower two years after weight-loss surgery, while bone marrow fat, a marker of bone weakening, increased, suggesting that weight-loss surgery it has negative effects on bone health,” Dr. Bredella said.

Dr. Bredella notes that the teenage years are a critical time for developing bone mass, and deficits in bone accumulation during these years could have a long-term impact on bone health and fracture risk in this older population. young later in life.

“As bariatric surgery is increasingly performed in adolescents, its effect on bone health needs to be emphasized, especially for physicians who will continue to provide routine medical care to these patients,” Dr. Bredella said. “We hope our study raises awareness about the effects of weight-loss surgery on the bones of adolescents with obesity.”

Raising awareness of the importance of bone health will allow for monitoring and management of low bone mass, optimal dietary supplementation with vitamin D and calcium, and initiation of appropriate therapy if necessary, Dr. Bredella noted.

“Our observed effects of weight-loss surgery on bone strength and bone marrow fat could also identify new targets for novel therapies,” he said.

In conclusion , our 24-month prospective longitudinal study showed that sleeve gastrectomy in adolescents and young adults impairs bone health , with a reduction in bone biomechanical properties and an increase in lumbar bone marrow adipose tissue (BMAT). compared to control participants who did not undergo surgery. These changes were largely explained by reductions in body mass index. A longer-term study based on clinical outcomes, such as fractures, would be required to further investigate the impact of reducing bone biomechanical parameters and increasing BMAT on fracture risk.