Bariatric Surgery Found to Increase Fracture Risk

Gastric bypass (Roux-en-Y) was performed in 90% of the subjects, while 10% had either vertical banded gastroplasty or biliopancreatic diversion. Eighty-six of the subjects were women.

The findings, adjusted for age and gender factors, showed that 21 individuals experienced 31 fractures within an average of seven years after surgery. The surgical patients' risk of a first fracture at any site was increased by 80%. The increased risk was 40% for a first fracture at the hip, wrist, spine, or arm; the risk of fracture at all other sites was doubled. The risk of hand or foot fracture was the most elevated, with an increase of more than threefold and almost fourfold, respectively. The study results were presented at the annual meeting of the Endocrinology Society, held during June 2009 in Washington (DC, USA).

"We knew there was a dramatic and extensive bone turnover and loss of bone density after bariatric surgery,” said senior author Jackie Clowes, M.D., Ph.D., a rheumatologist at the Mayo Clinic. "But we didn't know what that meant in terms of fractures. Although aggressive calcium and vitamin D supplementation after surgery may well help, it may still be insufficient to prevent the increased risk of fracture.”

Previous studies of patients following gastric bypass had found evidence that calcium, parathyroid hormone, and vitamin D metabolism are abnormal; despite supplementation, parathyroid hormone levels rise, calcium excretion declines, and serum levels of vitamin D remain nearly constant. Additionally, urine levels of N-telopeptide of type I collagen and serum osteocalcin--markers of bone turnover--also increase significantly.

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