A case-matched study of the differences in bone mineral density 1 year after 3 different bariatric procedures

Skeletal effects of sleeve gastrectomy, by sex and menopausal status and compared to Roux-en-Y gastric bypass surgery

CONTEXT

Roux-en-Y gastric bypass (RYGB) has deleterious effects on bone mass, microarchitecture, and strength. The skeletal effects of sleeve gastrectomy (SG), now the most commonly performed bariatric surgical procedure, are incompletely understood.

OBJECTIVE

We examined changes in bone turnover, areal and volumetric bone mineral density (aBMD, vBMD), and appendicular bone microarchitecture and estimated strength after SG. We compared the results to those previously reported after RYGB, hypothesizing lesser effects after SG than RYGB.

DESIGN, SETTING, PARTICIPANTS

Prospective observational cohort study of 54 adults with obesity undergoing SG at an academic center.

MAIN OUTCOME MEASURE(S)

Skeletal characterization with biochemical markers of bone turnover, dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and high-resolution peripheral QCT (HR-pQCT) was performed preoperatively and 6- and 12-months postoperatively.

RESULTS

Over 12 months, mean percentage weight loss was 28.8%. Bone turnover marker levels increased, and total hip aBMD decreased -8.0% (95% CI -9.1%, -6.7%, p<0.01). Spinal aBMD and vBMD declines were larger in postmenopausal women than men. Tibial and radial trabecular and cortical microstructure worsened, as did tibial estimated strength, particularly in postmenopausal women. When compared to data from a RYGB cohort with identical design and measurements, some SG biochemical, vBMD, and radial microstructural changes were smaller, while other changes were not.

CONCLUSIONS

Bone mass, microstructure, and strength decrease after SG. Some skeletal parameters change less after SG than after RYGB, while for others, we find no evidence for smaller effects after SG. Postmenopausal women may be at highest risk of skeletal consequences after SG.

Bone loss after bariatric surgery is observed mainly in the hip trabecular compartment and after hypoabsorptive techniques

We evaluated the impact of bariatric surgery on bone mineral density (BMD) and microarchitecture over one year using dual-energy X-ray absorptiometry (DXA), the trabecular bone score (TBS), and 3D-DXA to assess changes after different surgical techniques. This prospective, single-center study of 153 patients with severe obesity contrasts the effects on bone health of sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and duodenal switch/single anastomosis duodeno-ileostomy with sleeve gastrectomy (DS/SADIS). To our knowledge, this is the first study to evaluate patients undergoing DS/SADIS and to incorporate 3D-DXA analysis in the assessment of bone loss. Patients were 81 % female with a mean age of 50 ± 9 years. Fifty-four per cent underwent SG; 16 %, RYGB; and 30 %, DS/SADIS. Our findings revealed a significant decrease in areal BMD at the LS (-3.49 ± 5.44 %), FN (-5.24 ± 5.86 %), and TH (-8.06 ± 5.14 %) one year after bariatric surgery. Bone microarchitecture at the LS assessed by TBS was degraded in 30 % of patients. Proximal femur 3D-DXA analysis showed that surgery-induced bone loss predominantly affects the trabecular compartment (Trabecular volumetric (v) BMD: -8.00 ± 6.57 %) rather than the cortical compartment (Cortical vBMD: -1.37 ± 2.79 %). These results suggest hypoabsorptive and mixed techniques (DS/SADIS and RYGB) were associated with greater BMD loss and deterioration of microarchitecture than restrictive techniques (SG). The primary determinants of bone density and impairment of microarchitecture were the extent of weight loss and the type of surgical procedure. Despite overall bone loss, Z-score assessments indicated that post-surgical bone status remained within or above the average ranges compared to a healthy population, except for TH following DS/SADIS. In conclusion, our research shows differences in the impact of bariatric surgery techniques on bone density and microarchitecture, emphasizing the need for careful postoperative monitoring of bone health, particularly in patients undergoing hypoabsorptive and mixed procedures.

Skeletal effects of sleeve gastrectomy, by sex and menopausal status and in comparison to Roux-en-Y gastric bypass surgery

Context

Roux-en-Y gastric bypass (RYGB) has deleterious effects on bone mass, microarchitecture, and strength. Data are lacking on the skeletal effects of sleeve gastrectomy (SG), now the most commonly performed bariatric surgical procedure.

Objective

We examined changes in bone turnover, areal and volumetric bone mineral density (aBMD, vBMD), and appendicular bone microarchitecture and estimated strength after SG. We compared the results to those previously reported after RYGB, hypothesizing lesser effects after SG than RYGB.

Design Setting Participants

Prospective observational cohort study of 54 adults with obesity undergoing SG at an academic center.

Main Outcome Measures

Skeletal characterization with biochemical markers of bone turnover, dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and high-resolution peripheral QCT (HR-pQCT) was performed preoperatively and 6- and 12-months postoperatively.

Results

Over 12 months, mean percentage weight loss was 28.8%. Bone turnover marker levels increased, and total hip aBMD decreased -8.0% (95% CI -9.1%, -6.7%, p<0.01). Spinal aBMD and vBMD declines were larger in postmenopausal women than men. Tibial and radial trabecular and cortical microstructure worsened, as did tibial estimated strength, particularly in postmenopausal women. When compared to data from a RYGB cohort with identical design and measurements, some SG biochemical, vBMD, and radial microstructural parameters were smaller, while other changes were not.

Conclusions

Bone mass, microstructure, and strength decrease after SG. Some skeletal parameters change less after SG than after RYGB, while for others, we find no evidence for smaller effects after SG. Postmenopausal women may be at highest risk of skeletal consequences after SG.

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.

Skelettale Auswirkungen bariatrischer Chirurgie

Bei zunehmender Prävalenz der Adipositas sind in Deutschland ca. 54% der Bevölkerung übergewichtig oder adipös, wobei mit steigendem Übergewicht das Risiko für weitere Erkrankungen, wie z. B. Diabetes mellitus Typ 2, Herzinsuffizienz, arterielle Hypertonie u. a. stark ansteigt. Die Reduktion des Körpergewichtes ist daher aus verschiedenen Gesichtspunkten anzustreben. Viele Patientinnen und Patienten mit Adipositas haben bereits vor einer möglichen Operation einen Mangel an Vitamin D und Calcium und zeigen in Laboruntersuchungen entsprechende Defizite. Die konservative Behandlung der Adipositas aus Ernährungs-, Bewegung- und Verhaltenstherapie bildet die Basis der möglichen Therapiemaßnahmen. Bei Versagen der konservativen Behandlungsoptionen ergibt sich ab einem Body-Mass-Index (BMI) von über 40 kg/m2 die Indikation zur operativen Therapie, ab einem BMI von 50 kg/m2 besteht unter bestimmten Voraussetzungen die primäre Indikation zur Durchführung einer bariatrisch-chirurgischen Maßnahme. Zu den in Deutschland am häufigsten empfohlenen operativen Verfahren, die in der Regel laparoskopisch durchgeführt werden, gehören weiterhin die Implantation eines Magenbands, die Bildung eines Magenschlauchs (Gastric-sleeve-Resektion), die Anlage eines proximalen Roux-en-Y-Magenbypass oder eines Omega-loop-Magenbypass. Neben der angestrebten Reduktion des Übergewichtes durch ihre restriktiven wie malabsorptiven Wirkungen führen diese OP-Methoden in unterschiedlichem Ausmaß zu Veränderungen des Kalzium-Stoffwechsels u. a. mit Hypocalcämie, Vitamin-D-Defizit und Erhöhung des Serum-Parathormons, was in einem erhöhten Frakturrisiko, Veränderungen der Knochendichte und der Mikroarchitektur des Knochens münden kann. In der Nachsorge nach bariatrischen Operationen sind daher eine ausreichende Supplementierung verschiedener Vitamine, Mineralien und Spurenelemente, die regelmäßige Kontrolle der Laborparameter und der Knochendichte sowie ein angepasstes körperliches Training wichtig. Aus osteologischer Sicht kommt bei diagnostizierter Osteoporose insbesondere eine intravenöse antiresorptive Therapie in Betracht.

Nutritional Status in Chinese Patients with Obesity Following Sleeve Gastrectomy/Roux-en-Y Gastric Bypass: A Retrospective Multicenter Cohort Study

Metabolic surgery (MS) is one of the most effective therapies for treating obesity. Due to the lack of multicenter cohort research on nutritional evaluations after surgery in Chinese patients, we explored the changes in nutritional status following MS in Chinese patients. This was a retrospective study of patients (n = 903) who underwent sleeve gastrectomy (SG) (n = 640) or Roux-en-Y gastric bypass (RYGB) (n = 263) for obesity at five different hospitals in China between 17 February 2011, and 20 December 2019. Major nutrients were evaluated at baseline and 1, 3, 6, and 12 months postoperatively. Hb levels decreased, and anemia prevalence increased at 12 months after MS in the premenopausal female group. Moreover, patients with preoperative anemia had an increased risk of postoperative anemia. The ferritin levels (p < 0.001) decreased and iron deficiency increased (p < 0.001) at 12 months after MS among premenopausal females. No significant changes in folate deficiency and vitamin B12 deficiency were found throughout the study. The bone mineral density (BMD) of the femoral neck, lumbar spine, and total hip significantly decreased from baseline to 12 months after MS; however, no new patients developed osteopenia or osteoporosis after MS. Based on 12 months of follow-up, premenopausal females presented a high incidence of anemia after MS. Although we found no differences in osteopenia and osteoporosis prevalence after MS, the BMD did decrease significantly, which suggests that nutrient supplements and long-term follow-up are especially necessary postoperation.

Effects of Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density and Bone Turnover Markers: A Systematic Review and Meta-Analysis

BACKGROUND

There is a growing interest in the post-operative bone-related effects of bariatric surgery. However, little is known about the comparative effects of the most commonly performed bariatric procedures, namely Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

OBJECTIVES

To systematically assess the differences in areal bone mineral density (aBMD) and biochemical and hormonal markers of bone metabolism among patients undergoing RYGB and SG.

METHODS

We conducted a systematic review and meta-analysis of studies aBMD at different sites, as well as bone-specific alkaline phosphatase (BALP), 25-OH-vitamin D, calcium and parathyroid hormone (PTH) after RYGB and SG.

RESULTS

Fourteen studies were included (717 patients, 50.63% in the RYGB arm). Based on data collected at 1 year, 2 years and > 2 years, there were no significant differences in aBMD measurements at the total hip, lumbar spine, femoral neck, and the whole body with no statistical heterogeneity among different comparisons. Patients in the RYGB group showed significantly higher concentrations of BALP at 1 year (SMD = 0.52, 95%CI, 0.23-0.81, p = 0.0004) and PTH at > 2 years of follow-up (SMD = 0.68, 95%CI, 0.31-1.05, p = 0.0003) compared to the SG group.

CONCLUSION

There were no significant differences in aBMD measurements at the hip, lumbar spine, femoral neck, and the total body following RYGB and SG procedures. However, BALP and PTH concentrations were significantly higher after RYGB surgeries compared to SG. Attention should be paid to patients undergoing RYGB to prevent the expected skeletal fragility over time.

Bariatric surgery and skeletal health: A narrative review and position statement for management by the European Calcified Tissue Society (ECTS)

CONTEXT

Numerous studies have demonstrated detrimental skeletal consequences following bariatric surgery.

METHODS

A working group of the European Calcified Tissue Society (ECTS) performed an updated review of existing literature on changes of bone turnover markers (BTMs), bone mineral density (BMD), and fracture risk following bariatric surgery and provided advice on management based on expert opinion.

LITERATURE REVIEW

Based on observational studies, bariatric surgery is associated with a 21-44% higher risk of all fractures. Fracture risk is time-dependent and increases approximately 3 years after bariatric surgery. The bariatric procedures that have a malabsorptive component (including Roux-en-Y Gastric bypass (RYGB) and biliopancreatic diversion (BPD)) have clearly been associated with the highest risk of fracture. The extent of high-turnover bone loss suggests a severe skeletal insult. This is associated with diminished bone strength and compromised microarchitecture. RYGB was the most performed bariatric procedure worldwide until very recently, when sleeve gastrectomy (SG) became more prominent. There is growing evidence that RYGB is associated with greater reduction in BMD, greater increase in BTMs, and higher risk of fractures compared with SG but RCTs on optimal management are still lacking.

EXPERT OPINION

In all patients, it is mandatory to treat vitamin D deficiency, to achieve adequate daily calcium and protein intake and to promote physical activity before and following bariatric surgery. In post-menopausal women and men older than 50 years, osteoporosis treatment would be reasonable in the presence of any of the following criteria: i) history of recent fragility fracture after 40 years of age, ii) BMD T-score ≤ -2 at hip or spine, iii) FRAX score with femoral neck BMD exceeding 20% for the 10-year major osteoporotic fracture probability or exceeding 3% for hip fracture. Zoledronate as first choice should be preferred due to intolerance of oral formulations and malabsorption. Zoledronate should be used with caution due to hypocemia risk. It is recommended to ensure adequate 25-OH vitamin D level and calcium supplementation before administering zoledronate.

CONCLUSIONS

The bariatric procedures that have a malabsorptive component have been associated with the highest turnover bone loss and risk of fracture. There is a knowledge gap on osteoporosis treatment in patients undergoing bariatric surgery. More research is necessary to direct and support guidelines.

Changes in bone mineral density following laparoscopic sleeve gastrectomy: 2-year outcomes

BACKGROUND

Emerging evidence suggests that sleeve gastrectomy (SG) leads to significant bone mineral density (BMD) losses, but there is a paucity of studies evaluating skeletal consequences beyond 12-months post-operatively.

OBJECTIVES

To evaluate BMD changes 2 years postoperatively.

SETTING

A university hospital.

METHODS

Thirty-three women (mean age: 34.4 ± 12.3 years) who underwent SG and completed 24 months of follow-up were evaluated prospectively at baseline and at 3 (M3), 6 (M6), 12 (M12), and 24 (M24) months postoperatively. Data collected included BMD at the total hip, femoral neck, and lumbar spine measured by dual-energy x-ray absorptiometry and anthropometrics, biochemical, nutritional, and physical activity parameters.

RESULTS

At M24, patients achieved a mean body mass index and excess weight loss of 32.4 ± 5.1 kg/m² and 64.5 ± 21.4%, respectively; however, weight stabilized at M12. Femoral neck BMD decreased significantly from baseline to M24 (.924 ± .124 versus .870 ± .129 g/cm², P < .001), with no change between M12 and M24 (P = .273). Total hip BMD decreased significantly from baseline to M24 (1.004 ± .105 versus .965 ± .132 g/cm², P < .001) but increased between M12 and M24 (P = .001). No significant changes were noted in lumbar spine BMD. The percentage of changes in the femoral neck and the total hip BMD from baseline to M24 positively correlated with postoperative excess weight loss (r = .352, P = .045, and r = .416, P = .018, respectively).

CONCLUSION

Despite notable weight loss, women who underwent SG experienced significant bone loss at the total hip and femoral neck more than 2 years postoperatively. Future studies should investigate intervention strategies to attenuate skeletal deterioration after SG.

The impact of preoperative vitamin administration on skeletal status following sleeve gastrectomy in young and middle-aged women: a randomized controlled trial

BACKGROUND

The appropriate strategies to minimize skeletal deterioration following bariatric surgeries are inconclusive. This randomized controlled trial evaluated the effect of preoperative vitamin supplementation on bone mineral density (BMD) and biochemical parameters in females post-sleeve gastrectomy (SG).

METHODS

Participants were randomized to a 2-month preoperative treatment with a multivitamin and vitamin D 4000 IU/d (intervention arm) or 1200 IU/d (control arm). Preoperative and 12-month postoperative follow-up evaluations included anthropometrics, biochemical parameters, and dual energy X-ray absorptiometry (DEXA).

RESULTS

Sixty-two females (median age 29.7 years and median BMI 43.4 kg/m²) were recruited, 87% completed the 12-month follow-up. For the intervention and control arms, significant and similar reductions at 12-months post-surgery were observed in BMD of the hip (-6.8 ± 3.7% vs. -6.0 ± 3.6%; P = 0.646) and of the femoral neck (-7.1 ± 5.8% vs. -7.2 ± 5.5%; P = 0.973). For the intervention compared to the control arm, the 25 hydroxyvitamin D (25(OH)D) increment was greater after 2 months treatment, and vitamin D deficiency rates were lower at 3 and 6-months follow-up (P < 0.016). However, at 12-months postoperative, 25(OH)D values and vitamin D deficiency were comparable between the arms (P > 0.339). Predictors for BMD decline in the total hip were the percentage of excess weight-loss, age>50 years, and lower initial BMI (P ≤ 0.003).

CONCLUSIONS

SG was associated with a significant decline in BMD of the hip and femoral neck in young and middle-aged women, and was unaffected by preoperative vitamin D supplementation. Females who are peri-menopausal or with greater postoperative weight-loss should be particularly followed for BMD decline.

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density in Zucker Diabetic Fatty Rats: A Short-Term Comparative Study

BACKGROUND

While bariatric surgery could result in weight loss as well as glycaemia improvement, the short-term impact on bone health in a high glycemic environment following Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) remains intriguing.

OBJECTIVE

The aim of this study was to compare the short-term effects of RYGB and SG procedures on bone health in Zucker diabetic fatty (ZDFfa/fa) rats.

METHODS

Thirty age-matched male ZDFfa/fa rats were randomized into RYGB, SG, and sham groups after establishment of the diabetic model. Body weight, blood glucose, bone mineral density (BMD), the level of bone turnover markers (BTM), vitamin D, and serum calcium and phosphorus were measured 4 weeks after the operation.

RESULTS

The RYGB procedure brought about lower blood glucose, BMD, serum calcium and phosphorus levels, as well as a relatively higher bone turnover rate and 1,25(OH)2VD level, compared to the SG and sham groups, while the influences of the SG procedure were not significant. 25(OH)VD demonstrated no significant difference among the 3 groups.

CONCLUSIONS

Despite its excellent ability to provide short-term glycemic control, the RYGB procedure could led to more severe impairment of bone health compared to the SG procedure. Bone health should be procured after bariatric surgery, especially with the RYGB procedure. Early detection of BMD and BTM may help to avoid deterioration of bone.

Bone Mineral Density and Turnover After Sleeve Gastrectomy and Gastric Bypass: A Randomized Controlled Trial (Oseberg)

CONTEXT

Bariatric surgery, particularly Roux-en-Y gastric bypass (RYGB), is associated with an increased risk of osteoporotic fractures. It is unknown whether RYGB or sleeve gastrectomy (SG) have different effects on bone health.

OBJECTIVE

To compare changes in bone mineral density and markers of bone turnover 1 year after SG and RYGB.

DESIGN, SETTING, PATIENTS, AND INTERVENTIONS

Randomized, triple-blind, single-center trial at a tertiary care center in Norway. The primary outcome was diabetes remission. Patients with severe obesity and type 2 diabetes were randomized and allocated (1:1) to SG or RYGB.

MAIN OUTCOME MEASURES

Changes in areal bone mineral density (aBMD) and bone turnover markers.

RESULTS

Femoral neck, total hip, and lumbar spine aBMD, but not total body aBMD, decreased significantly more after RYGB (n = 44) than after SG (n = 48) (mean [95% confidence interval] between group differences -2.8% [-4.7 to -0.8], -3.0% [-5.0 to -0.9], -4.2% [-6.4 to -2.1], and -0.5% [-1.6 to 0.6], respectively). The increase in procollagen type 1 N-terminal propeptide (P1NP) and C-telopeptide of type I collagen (CTX-1) were approximately 100% higher after RYGB than after SG (between group difference at 1 year, both P < 0.001). The changes in femoral neck, total hip, and lumbar spine aBMDs and the changes in P1NP and CTX-1 were independently associated with the surgical procedure (all P < 0.05) and not weight change.

CONCLUSIONS

Roux-en-Y gastric bypass was associated with a greater reduction in aBMD and a greater increase in bone turnover markers compared with SG. This finding could suggest greater skeletal fragility after RYGB.

Three-year follow-up of bone status in male patients after bariatric surgery-a prospective single-center cohort study

BACKGROUND

In women, bariatric surgery (BS) leads to a decline in bone mineral density (BMD) and may ultimately lead to premature osteoporosis. The impact in men is largely unknown.

OBJECTIVE

To assess the effect of BS on bone metabolism in males.

SETTING

Single-center prospective cohort study.

METHODS

Twenty-four male BS candidates were prospectively enrolled. Anthropometric characteristics, serum gonadal hormones, markers of bone metabolism, and BMD were measured at baseline, 6-, 12- and 36-months postoperatively.

RESULTS

Roux-en-Y gastric bypass (RYGB) and adjustable gastric banding (AGB) were performed in 15 and 9 patients, respectively. Nineteen patients completed the 3-year follow-up. At 3 years, BMD of the right and left femur had decreased by 9.1 ± 7.2% and 9.4 ± 5.8% for RYGB and by 6.7 ± 3.9% and 4.5 ± 2.8% for AGB. Radius BMD had decreased by 14.0 ± 5.6% for RYGB and 5.9 ± 4.1% for AGB, i.e., significantly stronger for RYGB (P = .006). Serum parathyroid hormone increased in both groups and 13 of 19 patients developed Vitamin D deficiency. A significant increase of the bone resorption marker was seen only during the first year despite continuation of bone loss. Four patients developed de novo osteopenia or osteoporosis. No fractures were observed.

CONCLUSION

There are strong indications that male bone metabolism response after BS differs from female metabolism. The most affected site is the radius. In males, the cause of this BMD loss seems multifactorial, including mechanical unloading, hyperparathyroidism, and hypogonadism. However, clinical relevance remains unknown and therefore studies with longer-term follow-up are necessary.

Changes in Bone Mineral Density After Weight Loss Due to Metabolic Surgery or Lifestyle Intervention in Obese Patients

PURPOSE

Metabolic surgery and lifestyle intervention are two common methods used to treat obesity, but the effects of weight loss on bone mineral density (BMD) remain controversial. Our aim was to evaluate changes in BMD of the total hip, femoral neck, and lumbar spine after weight loss caused by metabolic surgery or lifestyle intervention.

MATERIALS AND METHODS

We searched PubMed, Web of Science, and the Cochrane Library to identify relevant studies published before 5 August 2020. The primary outcomes, including the BMD of the total hip, femoral neck, and lumbar spine before and 12 months after metabolic surgery or lifestyle intervention, were extracted.

RESULTS

A total of 19 studies with 1095 participants with obesity were included. Among them, 603 participants with obesity accepted metabolic surgery, while 492 accepted lifestyle intervention. At 12 months after weight loss, the BMD of the total hip decreased significantly in obese patients (mean difference [MD] = 0.06 g/cm²; 95% confidence interval [CI] 0.03 to 0.08; I² = 67%; P < 0.001), while the BMD of the lumbar spine did not significantly change (P > 0.05). In the subgroup analysis, the BMD of the femoral neck decreased significantly at 12 months in obese patients who underwent metabolic surgery (MD = 0.08 g/cm²; 95% CI 0.04 to 0.13; I² = 84%; P < 0.001), while it did not significantly change in obese patients who underwent lifestyle treatment (P > 0.05).

CONCLUSION

Regardless of whether the patients underwent metabolic surgery or lifestyle treatment, the BMD of the total hip significantly decreased in obese patients after weight loss. Different methods used to lose weight may have different effects on the BMD of the femoral neck. Prospective studies, preferably randomized controlled trials (RCTs), are still required to investigate whether the effects of the two treatments on bone metabolism are truly different.

Bone Density and Trabecular Morphology at Least 10 Years After Gastric Bypass and Gastric Banding

Roux-en-Y gastric bypass (RYGB) instigates high-turnover bone loss in the initial 5 years after surgery, whereas skeletal changes after adjustable gastric banding (AGB) are less pronounced. Long-term skeletal data are scarce, and the mechanisms of bone loss remain unclear. We sought to examine bone density and microarchitecture in RYGB and AGB patients a decade after surgery and to determine whether prior published reports of bone loss represent an appropriate adaptation to new postsurgical weight. In this cross-sectional study, 25 RYGB and 25 AGB subjects who had bariatric surgery ≥10 years ago were matched 1:1 with nonsurgical controls for age, sex, and current body mass index (BMI). We obtained bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), volumetric BMD and microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT), trabecular morphology by individual trabecular segmentation, and metabolic bone laboratory results. As compared with BMI-matched controls, RYGB subjects had significantly lower hip BMD, and lower total volumetric BMD at the distal radius and tibia. Substantial deficits in cortical and trabecular microarchitecture were observed in the RYGB group compared to controls, with reduced trabecular plate bone volume fraction and estimated failure load at both the radius and tibia, respectively. Bone turnover markers CTX and P1NP were 99% and 77% higher in the RYGB group than controls, respectively, with no differences in serum calcium, 25-hydroxyvitamin D, or parathyroid hormone. In contrast, the AGB group did not differ from their BMI-matched controls in any measured bone density, microarchitecture, or laboratory parameter. Thus, RYGB, but not AGB, is associated with lower than expected hip and peripheral BMD for the new weight setpoint, as well as deleterious changes in bone microarchitecture. These findings suggest that pathophysiologic processes other than mechanical unloading or secondary hyperparathyroidism contribute to bone loss after RYGB, and have important clinical implications for the long-term care of RYGB patients. © 2020 American Society for Bone and Mineral Research.

MANAGEMENT OF ENDOCRINE DISEASE: Bone complications of bariatric surgery: updates on sleeve gastrectomy, fractures, and interventions

Despite well recognized improvements in obesity-related comorbidities, increasing evidence implicates bariatric surgery in the onset of adverse skeletal health outcomes. The purpose of this review is to provide a focused update in three critical areas: (i) emergent data on sleeve gastrectomy and bone loss, (ii) evidence linking bariatric surgery to incident fracture, and (iii) intervention strategies designed to mitigate surgical bone loss. Better understanding of these issues will inform our treatment of skeletal health for patients planning bariatric surgery.

Bone mineral density changes after bariatric surgery

INTRODUCTION

Although bariatric surgery is associated with multiple health benefits, decreased bone mass is a known complication of the procedure. Roux-en-Y gastric bypass (RYGB) is associated with significant bone loss and increased fracture risk. However, data on the effect of sleeve gastrectomy (SG) on bone mineral changes are sparse. The impact of vitamin D and calcium levels on bone mineral density (BMD) after SG is also unknown.

METHODS

A retrospective chart review was performed to include patients who underwent RYGB or SG from 2014 to 2016 at a single institution. Patients were included if bone densitometry was performed preoperatively and within 2 years postoperatively. Serum 25-hydroxy vitamin D and calcium levels were collected preoperatively and at time of bone densitometry scan. BMD and T-score changes at the femoral neck, femoral trochanter, total hip, and lumbar spine were compared between RYGB and SG patients.

RESULTS

A total of 40 patients were included. 24 (60%) of patients underwent RYGB and 16 (40%) patients underwent SG. No statistically significant difference in baseline characteristics was noted between RYGB and SG patients. All measurements, except for serum 25-hydroxy vitamin D, were significantly decreased in RYGB patients, postoperatively. All measurements, except for BMD and T-score at the lumbar spine and serum 25-hydroxy vitamin D, were significantly decreased in SG patients, postoperatively. The extent of decrease in serum 25-hydroxyvitamin D was significantly associated with decreased BMD (p = 0.049) and T-score (p = 0.032) at the lumbar spine. The extent of decrease in serum calcium was significantly associated with decreased BMD (p = 0.046) at the femoral neck.

CONCLUSION

All patients were found to have decreased BMD after RYGB and SG. Surgery type was not a significant risk factor in BMD change. Despite vitamin D and calcium supplementation in all patients, a decrease in vitamin D and calcium levels were associated with a decrease in BMD. Close follow-up and treatment of vitamin D and calcium levels are warranted in all bariatric patients.

Roux-en-Y gastric bypass and gastric sleeve surgery result in long term bone loss

OBJECTIVES

Little is known about the long-term skeletal impact of bariatric procedures, particularly the increasingly commonly performed gastric sleeve surgery (GS). We examined bone density (BMD) change following three types of bariatric surgery Roux-en-Y gastric bypass (RYGB), GS and laparoscopic adjustable gastric banding (LAGB), compared with diet, over 36 months.

METHODS

Non-randomized, prospective study of participants with severe obesity (n = 52), undergoing weight-loss interventions: RYGB (n = 7), GS (n = 21), LAGB (n = 11) and diet (n = 13). Measurements of calciotropic indices, gut hormones (fasting and post prandial) peptide YY (PYY), glucagon-like peptide 1 (GLP1) and adiponectin together with dual-X-ray absorptiometry and quantitative computed tomography scans were performed thorough the study.

RESULTS

All groups lost weight during the first 12 months. Despite weight stability from 12 to 36 months and supplementation of calcium and vitamin D, there was progressive bone loss at the total hip (TH) over 36 months in RYGB -14% (95% CI: -12, -17) and GS -9% (95% CI: -7, -10). In RYGB forearm BMD also declined over 36 months -9% (95% CI: -6, -12) and LS BMD declined over the first 12 months -7% (95% CI: -3, -12). RYGB and GS groups experienced significantly greater bone loss until 36 months than LAGB and diet groups, which experienced no significant BMD loss. These bone losses remained significant after adjustment for weight loss and age. RYGB and GS procedures resulted in elevated postprandial PYY, adiponectin and bone turnover markers up to 36 months without such changes among LAGB and diet participants.

CONCLUSIONS

RYGB and GS but not LAGB resulted in ongoing TH bone loss for three postoperative years. For RYGB, bone loss was also observed at LS and non-weight-bearing forearms. These BMD changes were independent of weight and age differences. We, therefore, recommend close monitoring of bone health following RYGB and GS surgeries.

Recommendations Based on Evidence by the Andalusian Group for Nutrition Reflection and Investigation (GARIN) for the Pre- and Postoperative Management of Patients Undergoing Obesity Surgery

In order to develop evidence-based recommendations and expert consensus for nutrition management of patients undergoing bariatric surgery and postoperative follow-up, we conducted a systematic literature search using PRISMA methodology plus critical appraisal following the SIGN and AGREE-II procedures. The results were discussed among all members of the GARIN group, and all members answered a Likert scale questionnaire to assess the degree of support for every recommendation. Patients undergoing bariatric surgery should be screened preoperatively for some micronutrient deficiencies and treated accordingly. A VLCD (Very Low-Calorie Diet) should be used for 4-8 weeks prior to surgery. Postoperatively, a liquid diet should be maintained for a month, followed by a semi-solid diet also for one month. Protein requirements (1-1.5 g/kg) should be estimated using adjusted weight. Systematic use of specific multivitamin supplements is encouraged. Calcium citrate and vitamin D supplements should be used at higher doses than are currently recommended. The use of proton-pump inhibitors should be individualised, and vitamin B12 and iron should be supplemented in case of deficit. All patients, especially pregnant women, teenagers, and elderly patients require a multidisciplinary approach and specialised follow-up. These recommendations and suggestions regarding nutrition management when undergoing bariatric surgery and postoperative follow-up have direct clinical applicability.

Changes in Bone Mineral Density in Patients with Type 2 Diabetes After Different Bariatric Surgery Procedures and the Role of Gastrointestinal Hormones

BACKGROUND

To compare changes in bone mineral density (BMD) in patients with morbid obesity and type 2 diabetes (T2D) a year after being randomized to metabolic gastric bypass (mRYGB), sleeve gastrectomy (SG), and greater curvature plication (GCP). We also analyzed the association of gastrointestinal hormones with skeletal metabolism.

METHODS

Forty-five patients with T2D (mean BMI 39.4 ± 1.9 kg/m²) were randomly assigned to mRYGB, SG, or GCP. Before and 12 months after surgery, anthropometric, body composition, biochemical parameters, fasting plasma glucagon, ghrelin, and PYY as well as GLP-1, GLP-2, and insulin after a standard meal were determined.

RESULTS

After surgery, the decrease at femoral neck (FN) was similar but at lumbar spine (LS), it was greater in the mRYGB group compared with SG and GCP - 7.29 (4.6) vs. - 0.48 (3.9) vs. - 1.2 (2.7)%, p < 0.001. Osteocalcin and alkaline phosphatase increased more after mRYGB. Bone mineral content (BMC) at the LS after surgery correlated with fasting ghrelin (r = - 0.412, p = 0.01) and AUC for GLP-1 (r = - 0.402, p = 0.017). FN BMD at 12 months correlated with post-surgical fasting glucagon (r = 0.498, p = 0.04) and insulin AUC (r = 0.384, p = 0.030) and at LS with the AUC for GLP-1 in the same time period (r = - 0.335, p = 0.049). However, in the multiple regression analysis after adjusting for age, sex, and BMI, the type of surgery (mRYGB) remained the only factor associated with BMD reduction at LS and FN.

CONCLUSIONS

mRYGB induces greater deleterious effects on the bone at LS compared with SG and GCP, and gastrointestinal hormones do not play a major role in bone changes.

The curious fate of bone following bariatric surgery: bone effects of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) in mice

BACKGROUND

Bone loss and increased fracture risk following bariatric surgery has been reported. We investigated whether the two most commonly performed surgeries, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), lead to bone loss. In addition, we examined whether fortification of the diet with calcium citrate prevents bone loss.

METHODS

We used mouse models for SG and RYGB and compared bone loss with a group of sham mice with similar weight loss. All groups were switched at the time of surgery to a low-fat diet (LFD). We also examined whether fortification of the diet with calcium citrate and vitamin D was able to prevent bone loss.

RESULTS

At 2 weeks we observed no major bone effects. However, at 8 weeks, both trabecular and cortical bone were lost to the same extent after SG and RYGB, despite increased calcium absorption and adequate serum levels of calcium, vitamin D, and parathyroid hormone (PTH). Diet fortification with calcium citrate and vitamin D was able to partially prevent bone loss.

CONCLUSIONS

Both SG and RYGB lead to excess bone loss, despite intestinal adaptations to increase calcium absorption. Fortifying the diet with calcium citrate and vitamin D partly prevented the observed bone loss. This finding emphasizes the importance of nutritional support strategies after bariatric surgery, but also affirms that the exact mechanisms leading to bone loss after bariatric surgery remain elusive and thus warrant further research.

Long-Term Effects in Bone Mineral Density after Different Bariatric Procedures in Patients with Type 2 Diabetes: Outcomes of a Randomized Clinical Trial

There is scant evidence of the long-term effects of bariatric surgery on bone mineral density (BMD). We compared BMD changes in patients with severe obesity and type 2 diabetes (T2D) 5 years after randomization to metabolic gastric bypass (mRYGB), sleeve gastrectomy (SG) and greater curvature plication (GCP). We studied the influence of first year gastrointestinal hormone changes on final bone outcomes. Forty-five patients, averaging 49.4 (7.8) years old and body mass index (BMI) 39.4 (1.9) kg/m², were included. BMD at lumbar spine (LS) was lower after mRYGB compared to SG and GCP: 0.89 [0.82;0.94] vs. 1.04 [0.91;1.16] vs. 0.99 [0.89;1.12], p = 0.020. A higher percentage of LS osteopenia was present after mRYGB 78.6% vs. 33.3% vs. 50.0%, respectively. BMD reduction was greater in T2D remitters vs. non-remitters. Weight at fifth year predicted BMD changes at the femoral neck (FN) (adjusted R²: 0.3218; p = 0.002), and type of surgery (mRYGB) and menopause predicted BMD changes at LS (adjusted R²: 0.2507; p < 0.015). In conclusion, mRYGB produces higher deleterious effects on bone at LS compared to SG and GCP in the long-term. Women in menopause undergoing mRYGB are at highest risk of bone deterioration. Gastrointestinal hormone changes after surgery do not play a major role in BMD outcomes.

The Skeletal Consequences of Bariatric Surgery

PURPOSE OF REVIEW

This review outlines the recent findings regarding the impact of bariatric surgery on bone. It explores potential mechanisms for skeletal changes following bariatric surgery and strategies for management.

RECENT FINDINGS

Bone loss following bariatric surgery is multifactorial. Probable mechanisms include skeletal unloading, abnormalities in calciotropic hormones, and changes in gut hormones. Skeletal changes that occur after bariatric surgery are specific to procedure type and persist for several years post-operatively. Studies suggest that while bone loss begins early, fracture risk may be increased later in the post-operative course, particularly after Roux-en-Y gastric bypass (RYGB). Further research is needed to assess the extent to which skeletal changes following bariatric surgery result in fragility. Current management should be geared toward prevention of bone loss, correction of nutritional deficiencies, and incorporation of weight bearing exercise. Pharmacologic treatment should be considered for high-risk patients.

Fracture risk after three bariatric surgery procedures in Swedish obese subjects: up to 26 years follow-up of a controlled intervention study

BACKGROUND

Previous studies have reported an increased fracture risk after bariatric surgery.

OBJECTIVE

To investigate the association between different bariatric surgery procedures and fracture risk.

METHODS

Incidence rates and hazard ratios for fracture events were analysed in the Swedish Obese Subjects study; an ongoing, nonrandomized, prospective, controlled intervention study. Hazard ratios were adjusted for risk factors for osteoporosis and year of inclusion. Information on fracture events were captured from the Swedish National Patient Register. The current analysis includes 2007 patients treated with bariatric surgery (13.3% gastric bypass, 18.7% gastric banding, and 68.0% vertical banded gastroplasty) and 2040 control patients with obesity matched on group level based on 18 variables. Median follow-up was between 15.1 and 17.9 years for the different treatment groups.

RESULTS

During follow-up, the highest incidence rate for first-time fracture was observed in the gastric bypass group (22.9 per 1000 person-years). The corresponding incidence rates were 10.4, 10.7 and 9.3 per 1000 person-years for the vertical banded gastroplasty, gastric banding and control groups, respectively. The risk of fracture was increased in the gastric bypass group compared with the control group (adjusted hazard ratio [adjHR] 2.58; 95% confidence interval [CI] 2.02-3.31; P < 0.001), the gastric banding group (adjHR 1.99; 95%CI 1.41-2.82; P < 0.001), and the vertical banded gastroplasty group (adjHR 2.15; 95% CI 1.66-2.79; P < 0.001).

CONCLUSIONS

The risk of fracture is increased after gastric bypass surgery. Our findings highlight the need for long-term follow-up of bone health for patients undergoing this treatment.

Determining changes in bone metabolism after bariatric surgery in postmenopausal women

BACKGROUND

Accelerated bone loss is a known complication after bariatric surgery. Bone mineral density has been shown to decrease significantly after Laparoscopic Roux-en-Y gastric bypass (RYGB). Laparoscopic sleeve gastrectomy (SG) effects on bone density are largely unknown. This should be considered for those with increased preoperative risk for bone loss, such as postmenopausal females.

METHODS

This prospective clinical trial included postmenopausal patients, with BMI ≥ 35 k/m2, being evaluated for either RYGB or SG. Patients with history of osteoporosis, estrogen hormone replacement therapy, active smoking, glucocorticoid use, or weight > 295 lb were excluded. Patients underwent DEXA scans preoperatively and 1 year postoperatively with measurement of total body bone mineral density (BMD) and bone mineral content (BMC) as well as regional site-specific BMD and BMC.

RESULTS

A total of 28 patients were enrolled. 16 (57.1%) patients underwent RYGB and 12 (42.9%) patients underwent SG. Median preoperative BMI was 44.2 k/m2 (IQR 39.9, 46.6). Median change in BMI at 12 months was - 11.3 k/m2 (IQR - 12.8, - 7.9). A significant reduction in total body BMC was seen when comparing preoperative measurements to postoperative measurements (2358.32 vs 2280.68 grams; p = 0.002). Regional site BMC and BMD significantly decreased in the ribs and spine postoperatively (p = < 0.02) representing the greatest loss in the axial skeleton. Comparing those who underwent RYGB to SG there was no significant difference between the two groups when evaluating changes in total or regional site BMD.

CONCLUSION

Postmenopausal women were found to have decreased BMD and BMC after RYGB and SG, suggesting that high-risk women may benefit from postoperative DEXA screening. Further study is needed to determine the clinical significance of these findings. It is unknown if these changes in BMD are due to modifiable factors (Vitamin D level, activity level, hormone status, etc.), and whether BMD and BMC is recovered beyond 1 year.

Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures - 2019 Update: Cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPGs) was commissioned by the American Association of Clinical Endocrinologists (AACE), The Obesity Society (TOS), American Society for Metabolic and Bariatric Surgery (ASMBS), Obesity Medicine Association (OMA), and American Society of Anesthesiologists (ASA) Boards of Directors in adherence with the AACE 2017 protocol for standardized production of CPGs, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include: contextualization in an adiposity-based chronic disease complications-centric model, nuance-based and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current health care arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence based within the context of a chronic disease. A team approach to perioperative care is mandatory, with special attention to nutritional and metabolic issues.

Outcomes After Metabolic Surgery in Asians-a Meta-analysis

BACKGROUND

Obesity and type 2 diabetes mellitus (T2DM) are now increasingly epidemic in Asia. As obesity and T2DM have different disease patterns in Asians compared to Westerners, outcomes after metabolic surgery may differ. The aim of this meta-analysis was to gather the current available evidence on the outcomes after metabolic surgery in Asians.

METHODS

A literature search was conducted in September 2017. Four outcome measures were examined: (1) % excess weight loss (EWL), (2) post-intervention body mass index (BMI), (3) T2DM resolution or improvement, and (4) hypertension resolution.

RESULTS

Thirteen publications with a total of 1052 patients were analyzed, of which nine were randomized controlled trials, and four were case-matched studies. All the studies had a minimum follow-up duration of at least 1 year. % EWL was significantly higher in those who have undergone Roux-en-Y gastric bypass (RYGB) (SMD 0.53, 95% CI 0.12 to 0.94) versus sleeve gastrectomy (SG). T2DM resolution/improvement was favorable in those who have undergone RYGB (pooled OR 1.39, 95% CI 0.53 to 3.67) versus SG, although not statistically significant. Hypertension resolution was not significantly different between patients who have undergone SG versus RYGB (pooled OR 0.96, 95% CI 0.44 to 2.11).

CONCLUSION

RYGB results in better weight loss compared to SG in Asians, but the rate of T2DM resolution/improvement and improvement of hypertension appears to be similar. In Asian patients without symptoms of gastro-esophageal reflux disease in whom metabolic surgery is performed mainly for T2DM and metabolic syndrome, SG may be the surgery of choice.

Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures - 2019 update: cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic & Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPG) was commissioned by the American Association of Clinical Endocrinologists, The Obesity Society, the American Society of Metabolic and Bariatric Surgery, the Obesity Medicine Association, and the American Society of Anesthesiologists boards of directors in adherence to the American Association of Clinical Endocrinologists 2017 protocol for standardized production of CPG, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include contextualization in an adiposity-based, chronic disease complications-centric model, nuance-based, and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current healthcare arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence-based within the context of a chronic disease. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Changes in bone mineral density and bone metabolism after sleeve gastrectomy: a systematic review and meta-analysis

BACKGROUND

Roux-en-Y gastric bypass surgery adversely affects bone health. The evidence is less well-described for sleeve gastrectomy (SG).

OBJECTIVES

To better characterize bone metabolism changes after SG.

SETTING

Systematic review and meta-analysis.

METHODS

MEDLINE and EMBASE were searched through March 2019 for eligible studies assessing adults with obesity aged 18 years or older that underwent SG. Bone mineral density (BMD), serum calcium, serum phosphate, serum 25-hydroxyvitamin D, serum parathyroid hormone, or serum alkaline phosphatase were reported at baseline and after SG; and a follow-up duration was at least 6 months. Preoperative and postoperative mean of each outcome of interest and corresponding standard deviations were extracted from each study and the mean difference (MD) was calculated. Pooled MD was then calculated by combining MDs of each study using random-effects model.

RESULTS

A total of 22 studies with 1905 patients with obesity that underwent SG were included. There were significant decreases in total hip BMD (pooled MD of -.06 g/cm²; 95% confidence interval -.09 to -.03; I² = 0%) and femoral neck BMD (pooled MD of -.05 g/cm²; 95% confidence interval -.09 to -.02; I² = 0%) after SG. No significant change in lumbar spine BMD was observed. There were significant increases in serum calcium, serum 25-hydroxyvitamin D, and serum phosphate. Serum parathyroid hormone was significantly decreased. Serum alkaline phosphatase was not significantly altered after SG.

CONCLUSIONS

The present study found a decreased BMD among patients with obesity after SG.

Bone Health After Bariatric Surgery

Bariatric surgery results in long-term weight loss and improvement or resolution in obesity-related comorbidities. However, mounting evidence indicates that it adversely affects bone health. This review summarizes clinical research findings about the impact of bariatric surgery on skeletal outcomes. The literature is the largest and strongest for the Roux-en-Y gastric bypass (RYGB) procedure, as RYGB was the most commonly performed bariatric procedure worldwide until it was very recently overtaken by the sleeve gastrectomy (SG). Because SG is a newer procedure, its skeletal effects have not yet been well defined. Epidemiologic studies have now demonstrated an increased risk of fracture after RYGB and biliopancreatic diversion with duodenal switch, both of which include a malabsorptive component. As these epidemiologic data have emerged, patient-oriented studies have elucidated the bone tissue-level changes that may account for the heightened skeletal fragility. Bariatric surgery induces early and dramatic increases in biochemical markers of bone turnover. A notable feature of recent patient-oriented clinical studies is the application of advanced skeletal imaging modalities; studies address the limitations of dual-energy X-ray absorptiometry (DXA) by using quantitative computed tomography (QCT)-based modalities to examine volumetric bone mineral density and compartment-specific density and microstructure. RYGB results in pronounced declines in bone mass at the axial skeleton demonstrated by DXA and QCT, as well as at the appendicular skeleton demonstrated by high-resolution peripheral quantitative computed tomography (HR-pQCT). RYGB has detrimental effects on trabecular and cortical microarchitecture and estimated bone strength. Skeletal changes after RYGB appear early and continue even after weight loss plateaus and weight stabilizes. The skeletal effects of bariatric surgery are presumably multifactorial, and mechanisms may involve nutritional factors, mechanical unloading, hormonal factors, and changes in body composition and bone marrow fat. Clinical guidelines address bone health and may mitigate the negative skeletal effects of surgery, although more research is needed to direct and support such guidelines. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Caring for the Orthopaedic Patient With a History of Bariatric Surgery

Bariatric surgery is performed on the gastrointestinal tract as a solution to obesity, and prevalence of these surgical procedures continues to rise. Bariatric surgery creates restrictive and/or malabsorptive properties, causing nutritional deficits from the physiological changes in absorption and a hypoacidic environment. Although surgery induces sustained weight loss, decreases mortality, and provides resolution or improvement to comorbidities of obesity, it can also come with complications. Common long-term complications of bariatric surgery include malnutrition, anemia, impaired wound healing, and impaired bone health. It is essential that nurses and the healthcare team caring for orthopaedic individuals with a history of bariatric surgery be aware of the special needs of these individuals, especially in the promotion of bone health. Using a multidisciplinary approach for the advancement of the orthopaedic patient's health will help promote quality patient care.

Thin bones: Vitamin D and calcium handling after bariatric surgery

Bariatric surgery has proven to be a valuable treatment option for morbid obesity. However, these procedures can lead to impaired intestinal absorption of calcium and vitamin D, thereby challenging calcium homeostasis and possibly contributing to bone loss leading to an increased fracture risk. Besides calcium and vitamin D malabsorption, hormonal changes occurring after surgery can also be the source of observed bone loss. In this review, first, a case report will be discussed, highlighting the relevance of this topic. Afterwards, changes in bone density and fracture risk, after the two most performed types of bariatric surgery, Sleeve Gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB) will be discussed. In addition, we discuss the putative underlying mechanisms leading to bone changes based on both preclinical and clinical observations. Nonetheless, it is clear further research is needed to further elucidate the exact mechanisms of bone loss following bariatric surgery and subsequently identify potential treatment options for bone preservation.

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Bariatric surgery induces bone loss and leads to increased fracture risk.

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Bone resorption increases after both SG and, more strongly, after RYGB.

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Malabsorption and adipose tissue-related hormones likely contribute to bone loss.

Effects of Roux-en-Y gastric bypass and sleeve gastrectomy on bone mineral density and marrow adipose tissue

Bariatric surgery is associated with bone loss but skeletal consequences may differ between Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), the two most commonly performed bariatric procedures. Furthermore, severe weight loss is associated with high marrow adipose tissue (MAT); however, MAT is also increased in visceral adiposity. The purpose of our study was to determine the effects of RYGB and SG on BMD and MAT. We hypothesized that both bariatric procedures would lead to a decrease in BMD and MAT. We studied 21 adults with morbid obesity (mean BMI 44.1±5.1kg/m²) prior to and 12months after RYGB (n=11) and SG (n=10). All subjects underwent DXA and QCT of the lumbar spine and hip to assess aBMD and vBMD. Visceral (VAT) and subcutaneous (SAT) adipose tissue was quantified at L1-L2. MAT of the lumbar spine and femur was assessed by 1H-MR spectroscopy. Calcitropic hormones and bone turnover markers were determined. At 12months after surgery, mean weight and abdominal fat loss was similar between the RYGB and SG groups. Mean serum calcium, 25(OH)-vitamin D, and PTH levels were unchanged after surgery and within the normal range in both groups. Bone turnover markers P1NP and CTX increased within both groups and P1NP increased to a greater extent in the RYGB group (p=0.03). There were significant declines from baseline in spine aBMD and vBMD within the RYGB and SG groups, although the changes were not significantly different between groups (p=0.3). Total hip and femoral neck aBMD by DXA decreased to a greater extent in the RYGB than the SG group (p<0.04) although the change in femoral vBMD by QCT was not significantly different between groups (p>0.2). MAT content of the lumbar spine and femoral diaphysis did not change from baseline in the RYGB group but increased after SG (p=0.03). Within the SG group, 12-month change in weight and VAT were positively associated with 12-month change in MAT (p<0.04), suggesting that subjects with less weight and VAT loss had higher MAT. In conclusion, RYGB and SG are associated with declines in lumbar spine BMD, however, the changes are not significantly different between the groups. RYGB may be associated with greater decline of aBMD at the total hip and femoral neck compared to SG. MAT content increased after SG and this was associated with lower weight and VAT loss.

Influence of body weight on bone mass, architecture and turnover

Weight-dependent loading of the skeleton plays an important role in establishing and maintaining bone mass and strength. This review focuses on mechanical signaling induced by body weight as an essential mechanism for maintaining bone health. In addition, the skeletal effects of deviation from normal weight are discussed. The magnitude of mechanical strain experienced by bone during normal activities is remarkably similar among vertebrates, regardless of size, supporting the existence of a conserved regulatory mechanism, or mechanostat, that senses mechanical strain. The mechanostat functions as an adaptive mechanism to optimize bone mass and architecture based on prevailing mechanical strain. Changes in weight, due to altered mass, weightlessness (spaceflight), and hypergravity (modeled by centrifugation), induce an adaptive skeletal response. However, the precise mechanisms governing the skeletal response are incompletely understood. Furthermore, establishing whether the adaptive response maintains the mechanical competence of the skeleton has proven difficult, necessitating the development of surrogate measures of bone quality. The mechanostat is influenced by regulatory inputs to facilitate non-mechanical functions of the skeleton, such as mineral homeostasis, as well as hormones and energy/nutrient availability that support bone metabolism. Although the skeleton is very capable of adapting to changes in weight, the mechanostat has limits. At the limits, extreme deviations from normal weight and body composition are associated with impaired optimization of bone strength to prevailing body size.