Weight-Loss Surgery Negatively Impacts Skeletal Health

A new review of studies suggests that weight loss surgery can cause declines in bone mass and strength, and it is linked with an increased risk of bone fractures.

Researchers at Université Laval (Quebec City, Canada), the University of California, San Francisco (UCSF; USA), and other institutions conducted a review of six studies that examined the effects of various bariatric surgeries, and especially the Roux-en-Y gastric bypass (RYGB) procedure, which was the most commonly performed weight loss procedure worldwide until it was overtaken by sleeve gastrectomy (GS). But because sleeve gastrectomy is a newer procedure, its skeletal effects have not yet been well defined.

The results of the studies show an increased risk of fracture after RYGB and biliopancreatic diversion with duodenal switch, both of which include a malabsorptive component. Bariatric surgery also induces early and dramatic increases in biochemical markers of bone turnover, which may explain a heightened skeletal fragility. RYGB results in pronounced declines in bone mass at the axial skeleton--demonstrated by dual‐energy X‐ray absorptiometry (DXA) and quantitative computed tomography (QCT)--and at the appendicular skeleton--demonstrated by high‐resolution peripheral quantitative computed tomography (HR‐pQCT).

RYGB also has detrimental effects on trabecular and cortical microarchitecture and estimated bone strength. The review also shows that the skeletal changes after RYGB appear early on, and continue even after the weight loss plateaus and stabilizes. The researchers noted that nutritional factors, mechanical unloading, hormonal factors, and changes in body composition and bone marrow fat may contribute to poor bone health. The review was published on March 30, 2018, in JBMR Plus.

“Current clinical guidelines do address bone health, but most recommendations are based on low-quality evidence or expert opinion,” said study co-author Anne Schafer, MD, of UCSF and the San Francisco VA Health Care System (CA, USA). “The review's findings indicate that clinical guidelines on weight loss surgery should address bone health as a priority. Future studies should address strategies to avoid long-term skeletal consequences of these otherwise beneficial procedures.”

The RYGB procedure was the gold standard for surgical weight loss intervention for many years. The procedure usually involves laparoscopic minimally invasive surgery to create a stomach pouch from the larger stomach body. A portion of the small intestine is then connected to the stomach pouch, leaving a small opening for food to travel. The result is a sensation of satiety or fullness after eating small meals.

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Université Laval
University of California, San Francisco