Is the cure worse than obesity? The risks of a popular weight loss treatment for obese adolescents and young adults.
Childhood obesity is on the rise, and the best way to lose weight and improve cardiometabolic conditions is through weight-loss surgery.
Research published in Radiology, the journal of the Radiological Society of North America (RSNA), suggests that a prevalent weight-loss procedure performed on obese teenagers and young adults could potentially have detrimental consequences on bone health.
“This is the first study in adolescents and young adults that examined the long-term effects of sleeve gastrectomy,” remarks lead author Miriam A. Bredella, “the most common type of weight-loss surgery, on bone strength and bone marrow fat.”
Sleeve gastrectomy involves the surgical removal of around 75-80% of the stomach to limit food consumption and promote weight loss. The procedure transforms the normally round stomach into a tube-like structure. According to data from the American Society for Metabolic and Bariatric Surgery, the annual rate of sleeve gastrectomy procedures rose from just over 28,000 in 2011 to more than 122,000 in 2020, exceeding gastric bypass as the leading weight-loss surgery.
The research included participants aged 13 to 24 years from 2015 to 2020, all suffering from moderate to severe obesity. Adult participants had a body mass index (BMI) of 35 or more, which is considered obesity. The adolescent participants’ BMI was at or beyond 120% of the 95th percentile for their age and gender.
There were 54 participants, comprising 25 who underwent sleeve gastrectomy and 29 in the control group, with 41 participants being female. Participants in the surgical group had at least one co-morbidity related to obesity, or a BMI of 40 or more. The control group, though obese, did not plan to have the surgery and received diet and exercise advice instead.
The participants were examined physically, had blood tests, and underwent a quantitative CT scan of the lumbar spine both prior to and 24 months post sleeve gastrectomy. These measures helped to quantify volumetric bone mineral density and conduct finite element analysis, a method used for estimating bone strength. Quantitative CT is an extremely accurate method for identifying changes in volumetric bone mineral density following drastic weight loss.
As bone marrow fat can potentially indicate bone quality due to its responsiveness to nutritional alterations, proton MR spectroscopy was performed on patients to quantify lumbar spine bone marrow fat.
Two years post-surgery, the adolescents and young adults experienced a significant drop in BMI (-11.9, on average), whereas the control group saw a slight increase (+1.5, on average). Compared to the controls, the patients who underwent sleeve gastrectomy showed a substantial rise in bone marrow fat and a decrease in lumbar spine bone density and strength estimates.
“We found that bone strength was lower two years after weight-loss surgery, while bone marrow fat, a marker of bone weakening, was increased, suggesting that weight-loss surgery has negative effects on bone health,” adds Dr. Bredella.
Dr. Bredella emphasizes that the teenage years are a crucial period for accumulating bone mass. Any shortfall in bone development during this time could potentially affect their bone health in the long term and increase the risk of fractures for these younger individuals in the future.
“As bariatric surgery is increasingly performed in adolescents, its effect on bone health needs to be emphasized, especially to the physicians who will continue to provide routine medical care for these patients,” Dr. Bredella adds. “We hope that our study will raise awareness on the effects of weight-loss surgery on bones in adolescents with obesity.”
Dr. Bredella highlighted that by increasing the awareness regarding the significance of bone health, it is possible to implement monitoring and management strategies for low bone mass. This can include ensuring adequate dietary supplementation with vitamin D and calcium, and, if required, beginning suitable treatment, she noted.
“Our observed effects of weight-loss surgery on bone strength and bone marrow fat might also identify new targets for novel therapies,” she adds.
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