Gastric Bypass May Be Associated with Bone Loss
Patients showed higher bone turnover, lower bone density in year after Roux-en-Y procedure
MONDAY, Sept. 29 (HealthDay News) -- Patients undergoing Roux-en-Y gastric bypass may be at risk of subsequent bone loss, according to research published in the October issue of the Journal of Clinical Endocrinology & Metabolism.
Jessica Fleischer, M.D., of the Columbia University College of Physicians and Surgeons in New York City, and colleagues analyzed data from 23 obese patients with a mean body mass index of 47 kg/m2. Eighteen (78 percent) were women, and 10 of the women were premenopausal. Calciotropic hormones and markers of bone turnover were measured before surgery and periodically during the following year.
Despite patients' substantially increased vitamin D and calcium intake, 24-hour urinary calcium decreased and serum 25-hydroxyvitamin D concentrations did not increase, the researchers report. Parathyroid hormone was elevated at three months but returned to baseline by six months. Markers of bone turnover -- urinary N-telopeptide and serum osteocalcin -- began to rise at three months and continued to increase during the year. In addition, bone mineral density fell at the femoral neck and total hip.
"The preferential loss of bone at the hip, a weight-bearing site, suggests that this could be a response to unloading of the skeleton. This change in mechanical stress as a cause for remodeling, leads to elevations in bone turnover and subsequent reductions in bone mineral density. The strong association between extent of weight loss and amount of bone loss provides further support for this hypothesis," the authors write.