Marlene Busko

October 27, 2015

SEATTLE — A multipronged approach reduced bone loss and loss of lean muscle in obese patients who underwent bariatric surgery to lose weight, in the Bone Metabolism after Bariatric Surgery (BABS) study.

Specifically, in a cohort of middle-aged obese patients in Austria who underwent laparoscopic Roux-en-Y gastric bypass or sleeve gastrectomy, those who received the intervention — high-dose vitamin D loading before surgery, then vitamin D, calcium, and protein supplements along with an individualized exercise program after surgery — had a decelerated loss of bone-mineral density and lean body mass and a less pronounced increase in bone-turnover makers than other patients.

Thus, dietary "supplementation and exercise has a positive effect on the long-term outcome [of] bone protection after bariatric surgery, and it should be recommended for all patients undergoing this type of surgery," said Christian Muschitz, MD, from St Vincent Hospital of the Medical University of Vienna, Austria, in an oral session at the American Society for Bone and Mineral Research (ASBMR) 2015 Annual Meeting. The study was also reported in a poster at the meeting and was published online in the Journal of Bone and Mineral Research.

"The most striking feature for us is the trabecular bone score," Dr Muschitz told Medscape Medical News. The score declined "in the intervention group until month 6, [but] from [there] on it's a plateau, suggesting that there is a stop in the deterioration of trabecular bone quality." It is also noteworthy that there was less of a decline in lean-muscle mass (sarcopenia) among patients who took the protein supplements, he added.

The take-away message is "we have to implement specific dietary recommendations and physical exercise…to avoid this rapid and ongoing decline" in bone-mineral density, he stressed. For example, as shown in a study in Canada by Catherine Rousseau, from Laval University, in Quebec City, and colleagues that was presented in another poster, the number of fractures increased after 4 years. "They show an increase in the number of fractures. We show a decrease in bone-mineral density. It fits together."

Diet and Exercise to Preserve Bone

"Both Roux-en Y gastric bypass and sleeve gastrectomy lead to a decline in bone-mineral density, a deterioration in bone structure, and an increase in bone resorption up to 6 years after surgery," the researchers write.

Dr Muschitz added, "Almost all patients [who have gastric-bypass or sleeve-gastrectomy surgery] have a kind of secondary hyperparathyroidism and vitamin D deficiency."

The group hypothesized that patients who received dietary supplements and upped their exercise would have a lesser degree of these negative changes in bone metabolism, bone-mineral density, and body composition after bariatric surgery.

BABS was a prospective, open-label study that enrolled 220 premenopausal women and similarly aged men with a body mass index (BMI) of at least 38 kg/m2 who underwent Roux-en-Y gastric bypass or sleeve gastrectomy at their center.

From October 2011, they randomized 110 patients to the intervention arm and 110 patients to the control arm. The patients had a mean age of 41 and a mean BMI of 44, and 42% were men.

Before surgery, patients in the intervention arm received 28,000-IU cholecalciferol (vitamin D3) per week, given as sublingual drops, for 8 weeks. After surgery, they received 16,000-IU sublingual cholecalciferol per week, 1000-mg calcium monocitrate per day (taken in four parts), and a daily BMI-adjusted protein supplement. They also participated in a monitored exercise program of 45 minutes of aerobic Nordic walking (at an intensity adapted to their target heart rate) at least three times a week plus 30 minutes of muscle-strength training at least twice a week.

Patients in the control group did not receive the dietary supplements or individualized exercise program.

Bone-turnover markers were measured prior to surgery, and at 1, 3, 6, 9, 12, 18, and 24 months. Bone-mineral density was assessed using dual-energy X-ray absorptiometry (DEXA) before surgery and at 6, 12, 18, and 24 months.

The intervention had a positive effect on markers of bone turnover. Patients in the intervention group had a smaller increase in serum levels of sclerostin and cross-linked C-telopeptide (CTX) levels and a smaller decline in Dickkopf-1 (DKK-1) than patients in the nonintervention group, and their parathyroid-hormone (PTH) levels were closer to normal.

The intervention also had a positive effect on bone-mineral density. At 2 years after bariatric surgery, the decline in lumbar-spine, total-hip, and total-body bone-mineral density, as well as the changes in BMI, lean body mass, and trabecular bone score were all significantly less pronounced in the intervention group—regardless of the bariatric surgery type—than the control group (P < .005 for all).

The researchers plan to follow these individuals to gather longer-term data.

Dr Muschitz has has received speaker honoraria from Amgen, Novartis, Servier, Eli Lilly, Nycomed Pharma/Takeda, Kwizda Pharma, Boehringer Ingelheim, Actavis, and Daiichi-Sankyo and educational grants/research support from the Austrian Society for Bone and Mineral Research, Roche Austria, Eli Lilly Austria, Eli Lilly International, and Amgen Austria. Disclosures for the coauthors are listed in the paper.

J Bone Miner Res. Published online September 30, 2015. Article


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