Weight loss surgery may cause bone loss

Regarded as the most effective treatment for severe obesity, bariatric surgery may lead to bone loss for at least two years even after the body weight stabilises, says a study.

“The long term consequences of this substantial bone loss are unclear but it might put them at increased risk of fracture or breaking a bone,” said Elaine Yu, endocrinologist at Massachusetts General Hospital, Boston in the US.

“Therefore, bone health may need to be monitored in patients undergoing bariatric surgery,” she added.

For the study, researchers measured bone density using three-dimensional computed tomography (CT) called quantitative CT and dual-energy x-ray absorptiometry, also called DXA.

They compared bone density at the lower spine and the hip in 50 very obese adults. Two years later, bone density was 5-7 percent lower at the spine and 7-10 percent lower at the hip in the surgical group compared with the non-surgical control group.

“The bone loss in the surgical patients,” Yu said, “occurred despite the fact that they were not losing any more weight in the second year after surgery and had stable blood levels of calcium and vitamin D.” “Therefore, the cause of the bone loss is probably not related to weight loss itself,” she added.