Long-term trajectories of bone metabolism parameters and bone mineral density (BMD) in obese patients treated with metabolic surgery: a real-world, retrospective study

Short-term effects of Roux-en-Y gastric bypass or gastric sleeve on bone mineral density and calciotropic hormones: a systematic review and meta-analysis

Roux-en-Y gastric bypass (RYGB) and gastric sleeve (GS) have been associated with significant reductions in bone mineral density (BMD) and fluctuations in serum levels of calciotropic hormones. These changes pose a risk to bone health. The study assessed the short-term (12 and 24 months) effects of RYGB and GS on BMD and calciotropic hormones. PubMed, Embase, and Cochrane Library databases were searched. Analyses considered follow-up (12 and 24 months) with BMD as main outcome at three sites (femoral neck, total hip, and lumbar spine) and one for each calciotropic hormone (25 OH vitamin D and parathyroid hormone [PTH]). Estimated effect sizes were calculated as standardized mean differences (SMD), confidence interval of 95%, and P value. Nine studies totaling 473 participants (RYGB = 261 and GS = 212) were included. RYGB resulted in lower BMD than GS at 12 months for femoral neck (SMD = -0.485, 95% CI [-0.768, -0.202], P = .001), lumbar spine (SMD = -0.471, 95% CI [-0.851, -0.092], P = .015), and total hip (SMD = -0.616, 95% CI [-0.972, -0.259], P = .001), and at 24 months for total hip (SMD = -0.572, 95% CI [-0.907, -0.238], P = .001). At 24 months, 25 OH vitamin D was lower in RYGB than GS (SMD = -0.958 [-1.670, -0.245], P = .008) and PTH levels were higher in RYGB than in GS (SMD = 0.968 [0.132, 1.804, P = .023]). RYGB demonstrated significant reduction in regional BMD. It also induces lower serum 25 OH vitamin D and higher PTH levels than GS. The results support the need for preventive bone health measures in the short-term postoperative period, especially in the case of RYGB.

Long-Term Differential Effects of Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density

Context

The association of obesity with bone fragility fractures is complex and non-linear. Despite good efficacy on weight loss, bariatric surgery (BS) is also associated with bone loss. However, we lack information on risk factors of the long-term deleterious effects of BS on the skeleton.

Objective

We aimed to assess the factors associated with low bone mineral density (BMD) performed a long time after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG).

Methods

This cross-sectional study involved patients at a long distance from their BS that underwent dual-energy x-ray absorptiometry (DXA) with biological factors (vitamins, micronutrients, bone and inflammation biomarkers). Simple and multiple linear models (stepwise and parsimony approach) were developed.

Results

A total of 131 patients (91 RYGB, 40 SG) underwent DXA (51.8 ± 11.08 years, 87.8% women). At a mean of 6.8 ± 3.7 years after surgery, the mean weight loss was -28.6 ± 9.6%, and only 6 patients (5.7%) had a T-score less than or equal to -2.5. On univariate analysis, BMD was lower in the RYGB than in the SG group (P < .001) at all sites, despite similar fat and fat-free mass and weight loss. Serum parathyroid hormone and phosphate levels were higher in RYGB than SG patients. A total of 10.1% of patients showed vascular calcifications. On multivariable analysis, BMD remained different between surgery groups after adjustment for age, body mass index, ethnicity, and sex. The model-adjusted R 2 values were 0.451 for the total hip; 0.462 the femoral neck, and 0.191 the lumbar spine for the inflammation model; 0.458, 0.462, and 0.254, respectively, for the bone marker model; and 0.372, 0.396, and 0.142 for the vitamin model. Serum zinc, ferritin, and uric acid levels were the markers associated with BMD to a low extent.

Conclusion

BMD differed depending on the BS procedure. A few biological markers may be associated weakly with BMD well after the surgery.