Gastric banding induces negative bone remodelling in the absence of secondary hyperparathyroidism: potential role of serum C telopeptides for follow-up

Abstract

OBJECTIVE: Data about the consequences of laparoscopic adjustable gastric banding (LAGB) on phospho-calcic and bone metabolism remain scarce. SUBJECTS: We studied a group of 37 obese premenopausal women (age: 24-52 y; mean BMI ¼ 43.7 kg/m 2 ) who underwent LAGB. METHODS: Serum calcium, phosphate, alkaline phosphatase, parathormone (PTH), vitamin D 3, serum C-telopeptides, IGFBP-3 and IGF-1 were measured at baseline, 6, 12, 18 and 24 months after surgery. Body composition, bone mineral content (BMC) and density (BMD) were measured using dual-X-ray absorptiometry (DXA) at baseline, 6, 12 and 24 months after surgery. RESULTS: There was no clinically significant decrease of calcemia; PTH remained stable. Serum telopeptides increased by 100% (Po0.001) and serum IGFBP-3 decreased by 16% (Po0.001) during the first 6 months, and then stabilized, whereas IGF-1 remained stable over the 2 y. BMC and BMD decreased, especially at the femoral neck; this decrease was significantly correlated with the decrease of waist and hip circumference. CONCLUSIONS: We concluded that there was no evidence of secondary hyperparathyroidism 24 months after LAGB. The observed bone resorption could be linked to the decrease of IGFBP-3, although this decrease could be attributable to other confounding factors. Serum telopeptides seem to be a reliable marker of bone metabolism after gastric banding. DXA must be interpreted cautiously during major weight loss, because of the artefacts caused by the important variation of fat tissue after LAGB.

Effects of obesity treatments on bone mineral density, bone turnover and fracture risk in adults with overweight or obesity

“…This meta-analysis showed significantly lower BMD at the femoral neck in the surgical than in the non-surgical control group, but only by -0.005 g/cm 2 , with no difference between operated and non-operated groups in lumbar spine BMD [55]. This finding of reduced BMD at the hip but not the spine after bariatric surgery is in keeping with observations that although gastric banding has been shown to significantly reduce hip BMD [56], it is associated with a small, but significant, increase relative to pre-surgical values in lumbar spine BMD at 12 [62] and 24 months [57] after surgery.…”

Bone turnover after bariatric surgery

“…(15) and with other investigators, who employed different biochemical markers of bone formation (8,12). Moreover, urinary DPYD was also higher in BS patients than in Cont, indicating an increased bone resorption, as detected by other investigators (20,21), even when using different bone resorption markers as well (8,20,22,23). Therefore, an increased bone turnover has been clearly evidenced by the present findings, which corroborates with numerous reports (8,12,13,15,24), although not with all of them (9,21).…”

Vitamin D alteration associated with obesity and bariatric surgery

“…60 It seems that despite well-documented pre-operative vitamin D deficiency, this type of surgery does not disrupt the serum vitamin D levels that remain stable or increase, as well as the rate of PTH, which remains stable. 61,62 The VSG procedure can show a weight loss in the order of 20 to 30% after two years, which equates to a loss of excess weight in the range of 45 to 64%. 59,[63][64][65] In one of the first studies that focused on the phosphocalcic metabolism in this type of procedure, it was shown that if 95% of the patients were vitamin D-deficient and had high levels of PTH in the study prior to surgery, in post-operative, 25-hydroxy vitamin D levels increased and those of PTH decreased.…”