Weight Loss Surgery and Bone Loss

There is brand new evidence that patients are experiencing significant bone loss following weight loss surgery. Weight Loss Surgery, known by its general term Bariatric Surgery, is a branch of medicine that deals with the treatment of obesity and includes operations such as the gastric bypass and stomach banding. Although these operations have proven successful in significant and sustained weight loss, a new study, published in October 2008 by the Columbia University College of Physicians and Surgeons in New York provides the proof that weight loss surgery does indeed cause bone loss.

How Weight Loss Surgery May Cause Bone Loss

It has been known for a long time in the medical community that weight loss surgery is extremely hard on our body’s skeleton. Post bariatric surgery patients were found to have notable deficiencies in Vitamin D and calcium absorption. Medical science does not yet know exactly why this occurs but it is believed the changes to the gastrointestinal tract during the surgical procedures adversely affect the absorption rate of these important minerals.

Dr. Shonni Silverberg, Professor of Medicine at Columbia U, co-authored the results of this year’s long study into bone loss after bariatric surgeries (*see bottom of page for full citation). For the purposes of this study, patient levels for calcium, Vitamin D and hormones were measured prior to surgery, and then again at 3, 6, and 12 months after the operation. Bone density samples were taken from both the hip and the femoral neck (top of the thigh bone) for measurement. It became very obvious that those who lost the most weight also lost the most bone mass. On average patients lost about 100lbs. One year after weight loss surgery those same patients registered density losses of 8% from the hip bone and 9.2% of the femoral neck. Furthermore it was noted that the bone loss occurs very early on in the recovery from surgery, even before any actual weight loss occurs and it is not known how much more bone density is lost over an even lengthier period of time.

With obesity on the rise in North America more and more people are opting for weight loss surgery when all else fails. Further bone status studies are needed to research bone quality and fracture risks. To date only short term effects have been studied into the deficiencies in absorption of Vitamin D and calcium post bariatric surgery and little to nil is known about long term results. On a positive note, Dr. Silverberg’s research has clearly made it imperative to include supplemental nutrients in post operative care to rebalance calcium and Vitamin D levels for patients who have undergone weight loss surgery.

*Citation: Fleischer J, Stein EM, Bessler M, Badia MD, Restuccia N, Olivero-Rivera L, McMahon DJ,  Silverberg SJ. The decline in hip bone density following gastric bypass surgery is associated with extent of weight loss.  J Clin Endocrinol Metab. Rapid Electronic Publication first published on Jul 22, 2008 as doi:10.1210/jc.2008-0481.