Bone Loss Remains Concern For Gastric Bypass Patients Following Surgery

A recent study of patients who underwent bariatric surgery showed that even while their weight settled following their procedure their bone loss continued even two years after the operation.

The results of the study were presented at the 2014 Joint Meeting of the International Society of Endocrinology and the Endocrine Society: ICE/ENDO 2014 in Chicago by Elaine Yu, MD, MSc, who served as the principal investigator. “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 Yu, who also works as an endocrinologist at Massachusetts General Hospital. “Therefore, bone health may need to be monitored in patients undergoing bariatric surgery.”

The most recent presentation followed earlier studies by Yu’s team which showed gastric bypass patients losing bone mineral density within the first year after surgery. Because of those results, the team extended their research to include the most recent study thanks to funding by the National Institutes of Health.

In some studies of bone mineral density a dual-energy ex-ray absorptiometry (DXA) has been shown to give inaccurate results so Yu’s team used a three-dimensional computed tomography (CT) quantitative CT. The study looked at the bone density of the lower spine and hip of 50 obese adults, including 30 who had had bariatric surgery and 20 who lost weight through nonsurgical means.

The patients who did not undergo surgery were deemed to be similar to the other members of the study based on several factors including age, sex and body mass index. Yu also said after the surgery almost all of the patients received calcium and vitamin D supplements. Two years after surgery the bone density of the surgical group had dropped between 5 and 7% at the spine and 7 to 10% at the hip in the surgical group compared to the nonsurgical study patients. The surgical patients also showed increases in markers of bone resorption according to Yu.

Looking at the results Yu said the bone loss even after weight loss had stopped and showed stable levels of calcium and vitamin D the bone loss was likely not related to the weight loss. While none of the surgical patients have needed treatment for osteoporosis, “The question is, when is the bone loss going to stop? Over time this could be a problem in terms of fracture.”

As a result of her study Yu recommended bariatric surgery patients who are at risk of osteoporosis receive bone density tests. She also said that while there are risks associated with gastric bypass, “This surgery is the most effective treatment for severe obesity and offers phenomenal health benefits.”