Bariatric surgery increases risk of bone fracture

Racial disparities in selected micronutrient deficiencies after bariatric surgery: A systematic review

BACKGROUND

Bariatric surgery has been associated with numerous micronutrient deficiencies. Several observational studies have found that these deficiencies are more common in racially/ethnically minoritized patients.

OBJECTIVES

To conduct a systematic review to investigate whether racially/ethnically minoritized patients experience worse nutritional outcomes after bariatric surgery.

SETTING

University of Wisconsin-Madison.

METHODS

PubMed, CINAHL, PsychINFO, and Cochrane databases were queried. We searched for manuscripts that reported micronutrient levels or conditions related to micronutrient deficiencies according to race/ethnicity (White, African American/Black, and Hispanic) after laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass between 2002 and 2022. Eleven micronutrients (vitamins A, B1 [thiamine], B12, D, E, K, calcium, copper, folate, iron, and zinc), and four conditions (anemia, bone loss, fractures, and hyperparathyroidism) were assessed.

RESULTS

Abstracts from 953 manuscripts were screened; 18 full-text manuscripts were reviewed for eligibility, and ten met the inclusion criteria. Compared to White patients, African Americans had a higher prevalence of thiamine, vitamin D, and vitamin A deficiencies. There were no differences in calcium and vitamin B12 deficiencies. The other six micronutrients were not assessed according to race/ethnicity. Hyperparathyroidism was more prevalent in African Americans than White patients in the three studies that evaluated it. The prevalence of fractures was mixed. Anemia and bone loss were not evaluated according to race/ethnicity.

CONCLUSIONS

Although the literature on micronutrient outcomes following bariatric surgery according to race/ethnicity is limited, African Americans appear to experience a higher prevalence of vitamin deficiencies and associated conditions. Qualitative and quantitative research to explore these disparities is warranted.

Obesity and Skeletal Fragility

Skeletal fracture has recently emerged as a complication of obesity. Given the normal or better than normal bone mineral density (BMD), the skeletal fragility of these patients appears to be a problem of bone quality rather than quantity. Type 2 diabetes mellitus (T2DM), the incidence of which increases with increasing body mass index, is also associated with an increased risk for fractures despite a normal or high BMD. With the additional bone pathology from diabetes itself, patients with both obesity and T2DM could have a worse skeletal profile. Clinically, however, there are no available methods for identifying those who are at higher risk for fractures or preventing fractures in this subgroup of patients. Weight loss, which is the cornerstone in the management of obesity (with or without T2DM), is also associated with an increased risk of bone loss. This review of the literature will focus on the skeletal manifestations associated with obesity, its interrelationship with the bone defects associated with T2DM, and the available approach to the bone health of patients suffering from obesity.

Risk of fracture following gastric surgery for benign and malignant conditions: A study level pooled analysis of population-based cohort studies

BACKGROUND

Metabolic changes may occur following gastric surgery, which has been reported to contribute to bone loss, osteoporosis and even bone fracture. However, the evidence regarding the relationship between gastric surgery for benign and malignant conditions and risk of fracture is controversial. This study was conducted with the aim to evaluate whether gastric surgery is associated with a high risk of fracture.

METHODS

Major electronic databases were searched from inception through October 2021 for population-based cohort studies investigating the associations between gastric surgery (including bariatric gastric surgeries and surgeries for gastric benign and malignant gastric tumors) and risk of fracture compared with controls. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were derived using the random-effects Mantel-Haenszel model. Multiple subgroup analyses and sensitivity analyses were carried out to test sources of heterogeneity stratified by various study characteristics and the robustness of the results.

RESULTS

A total of 14 studies comprising 693134 individuals were identified for analysis. The RR for the risk of fracture in people undergoing gastric surgery was 1.45 [95% confidence interval (CI) 1.23 - 1.72; I^{2 =} 95.8%; P < 0.001] compared with that in control populations, among which the fracture sites of upper limb, spine, lower limb, pelvis and hip showed consistent significant results (all P < 0.05), whereas nonsignificant associations was noted for other fracture sites. Significant associations were also observed for patients having total or subtotal gastrectomy (RR 2.22, 95% CI 1.66 to 3.00), gastric bypass (RR 1.48, 95% CI 1.26 to 1.74), and a similar trend was observed for preserved passage procedures (including sleeve gastrectomy, gastric banding, vertical banded gastroplasty and other procedures that preserved the passage through the duodenum and proximal small bowel, in contrast to gastric bypass), though the difference did not reach statistically significant (RR 1.10, 95% CI 0.95 to 1.26). An evident increased risk in the age range from 40-59 years was observed (40-49 years: RR 1.36, 95% CI 1.19-1.55; 50-59 years: RR 2.48, 95% CI 1.58-3.90).

CONCLUSION

From this large pooled analysis of population-based cohort studies, evidence supports that fracture risk is increased in gastric surgery survivors compared with the control population. Early prevention and effective intervention strategies of bone fracture should be taken from clinicians and health policy makers.

CLINICAL TRIAL REGISTRATION

PROSPERO (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=291394), identifier CRD42021291394.

Musculoskeletal effects of obesity and bariatric surgery – a narrative review

Obesity affects several areas of the human body, leading to increased morbidity and mortality and the likelihood of other diseases, such as type 2 diabetes mellitus, cardiovascular diseases and musculoskeletal disorders. These conditions predispose to bone fractures and sarcopenic obesity, defined by the presence of an obesity-associated decrease in muscle mass and strength. Both bone fragility and sarcopenic obesity disease are consequences of several factors, such as a low degree of chronic inflammation, insulin resistance, hormonal changes, nutritional deficiencies, ectopic fat deposits and sedentary lifestyle. The diagnosis of obesity-related musculoskeletal disorders is limited by the lack of sarcopenia criteria and lower accuracy of bone mineral density measurement by dual-energy X-ray absorptiometry in overweight people. Reducing body weight provides undeniable benefits to this population, however treating cases of severe obesity with bariatric surgery can cause even greater damage to bone and muscle health, especially in the long term. The mechanisms involved in this process are not yet fully understood, but factors related to nutrient malabsorption and mechanical discharge as well as changes in gut hormones, adipokines and bone marrow adiposity should be taken into account. Depending on the surgical technique performed, greater musculoskeletal damage may occur, especially in cases of malabsorptive surgeries such as Roux-en-Y gastric bypass, when compared to restrictive techniques such as sleeve gastrectomy. This difference is probably due to greater weight loss, nutrient malabsorption and important hormonal changes that occur as a consequence of the diversion of intestinal transit and loss of greater absorptive surface. Thus, people undergoing bariatric procedures, especially malabsorptive ones, should have their musculoskeletal health supervised to allow early diagnosis and appropriate therapeutic interventions to prevent osteoporotic fractures and preserve the functionality of the skeletal muscles.

BONE HEALTH ASSESSMENT OF ELDERLY PATIENTS UNDERGOING BARIATRIC SURGERY

BACKGROUND

Bariatric surgery promotes changes in body composition, that can include the loss of bone mineral density (BMD). There is a lack of studies on the evolution of bone health of elderly people who underwent bariatric surgery, in general, and when comparing the gastric bypass (GB) and sleeve gastrectomy (SG) techniques.

OBJECTIVE

To evaluate the bone health of elderly patients with obesity undergoing bariatric surgery.

METHODS

This is a prospective randomized clinical study, that was carried out with individuals of both sexes, ≥65 years, undergoing GB or SG and who met the inclusion criteria. Age, gender and comorbidities (type 2 diabetes mellitus, arterial hypertension, dyslipidemia and osteoarthrosis) were collected and analyzed at baseline. Anthropometric data (weight, body mass index, percentage of weight loss, percentage of excess weight loss), laboratory tests related to bone health and bone mineral density were analyzed before and 24 months after surgery.

RESULTS

A total of 36 patients (GB, n=18; SG, n=18) were evaluated. At baseline, except for sex and preoperative body mass index, which was higher in GB, groups were similar. After 24 months, GB was superior for weight loss (%WL) and excess weight loss (%EWL). Regarding bone health, a significant decrease of BMD was observed in the spine, total proximal femur and femoral neck in all groups, with an average decrease of 5.1%, 10.5% and 15.1%, respectively. In addition, the observed decrease in BMD was up to 25% in the total femur after 24 months, six patients went from normal BMD to osteopenia and one from osteopenia to osteoporosis. There was no difference in parathormone values. However, there was an association between the increase in parathormone and the decrease in BMD in the spine, mainly in the GB group. There was no association between %WL and %EWL with the reduction in BMD.

CONCLUSION

Bariatric surgery was related to the reduction of BMD in elderly patients, but there was no statistical difference between the two surgical techniques.

Bariatric Surgery and Osteoporosis

It has been increasingly acknowledged that bariatric surgery adversely affects skeletal health. After bariatric surgery, the extent of high-turnover bone loss is much greater than what would be expected in the absence of a severe skeletal insult. Patients also experience a significant deterioration in bone microarchitecture and strength. There is now a growing body of evidence that suggests an association between bariatric surgery and higher fracture risk. Although the mechanisms underlying the high-turnover bone loss and increase in fracture risk after bariatric surgery are not fully understood, many factors seem to be involved. The usual suspects are nutritional factors and mechanical unloading, and the roles of gut hormones, adipokines, and bone marrow adiposity should be investigated further. Roux-en-Y gastric bypass (RYGB) was once the most commonly performed bariatric procedure worldwide, but sleeve gastrectomy (SG) has now become the predominant bariatric procedure. Accumulating evidence suggests that RYGB is associated with a greater reduction in BMD, a greater increase in markers of bone turnover, and a higher risk of fracture than SG. These findings should be taken into consideration in determining the most appropriate bariatric procedure for patients, especially those at higher fracture risk. Before and after all bariatric procedures, sufficient calcium, vitamin D and protein intake, and adequate physical activity, are needed to counteract negative impacts on bone. There are no studies to date that have evaluated the effect of osteoporosis treatment on high-turnover bone loss after bariatric surgery. However, in patients with a diagnosis of osteoporosis, anti-resorptive agents may be considered.

Cortical Bone Loss Following Gastric Bypass Surgery Is Not Primarily Endocortical

Roux-en Y gastric bypass (RYGB) surgery is an effective treatment for obesity; however, it may negatively impact skeletal health by increasing fracture risk. This increase may be the result not only of decreased bone mineral density but also of changes in bone microstructure, for example, increased cortical porosity. Increased tibial and radial cortical porosity of patients undergoing RYGB surgery has been observed as early as 6 months postoperatively; however, local microstructural changes and associated biological mechanisms driving this increase remain unclear. To provide insight, we studied the spatial distribution of cortical porosity in 42 women and men (aged 46 ± 12 years) after RYGB surgery. Distal tibias and radii were evaluated with high-resolution peripheral quantitative computed tomography (HR-pQCT) preoperatively and at 12 months postoperatively. Laminar analysis was used to determine cortical pore number and size within the endosteal, midcortical, and periosteal layers of the cortex. Paired t tests were used to compare baseline versus follow-up porosity parameters in each layer. Mixed models were used to compare longitudinal changes in laminar analysis outcomes between layers. We found that the midcortical (0.927 ± 0.607 mm-2 to 1.069 ± 0.654 mm-2 , p = 0.004; 0.439 ± 0.293 mm-2 to 0.509 ± 0.343 mm-2 , p = 0.03) and periosteal (0.642 ± 0.412 mm-2 to 0.843 ± 0.452 mm-2 , p < 0.0001; 0.171 ± 0.101 mm-2 to 0.230 ± 0.160 mm-2 , p = 0.003) layers underwent the greatest increases in porosity over the 12-month period at the distal tibia and radius, respectively. The endosteal layer, which had the greatest porosity at baseline, did not undergo significant porosity increase over the same period (1.234 ± 0.402 mm-2 to 1.259 ± 0.413 mm-2 , p = 0.49; 0.584 ± 0.290 mm-2 to 0.620 ± 0.299 mm-2 , p = 0.35) at the distal tibia and radius, respectively. An alternative baseline-mapping approach for endosteal boundary definition confirmed that cortical bone loss was not primarily endosteal. These findings indicate that increases in cortical porosity happen in regions distant from the endosteal surface, suggesting that the underlying mechanism driving the increase in cortical porosity is not merely endosteal trabecularization. © 2022 American Society for Bone and Mineral Research (ASBMR).

The Impact of Bariatric Surgery on Bone Health: State of the Art and New Recognized Links

Bariatric surgery (BS) is the most effective therapy for severe obesity, which improves several comorbidities (such as diabetes, hypertension, dyslipidemia, among others) and results in marked weight loss. Despite these consensual beneficial effects, sleeve gastrectomy and Roux-en-Y gastric bypass (the two main bariatric techniques) have also been associated with changes in bone metabolism and progressive bone loss. The objective of this literature review is to examine the impact of bariatric surgery on bone and its main metabolic links, and to analyze the latest findings regarding the risk of fracture among patients submitted to bariatric surgery.

Fracture risk following bariatric surgery: a systematic review and meta-analysis

Bariatric surgery may negatively impact bone health. We aimed to compare fracture risk following bariatric surgery by type (malabsorptive, restrictive), or to non-surgical weight loss, or to controls with obesity. We systematically searched four databases from inception until October 2020. We included observational and interventional studies on adults. We screened articles and abstracted data in duplicate and independently and assessed the risk of bias. We conducted random-effects model meta-analyses (Review Manager v5.3), to calculate the relative risk of any or site-specific fracture (CRD42019128536). We identified four trials of unclear-to-high risk of bias and 15 observational studies of fair-to-good quality. Data on fracture risk following bariatric surgery compared to medical weight loss is scarce and limited by the small number of participants. In observational studies, at a mean/median post-operative follow-up > 2 years, the relative risk of any fracture was 45% (p < 0.001) and 61% (p = 0.04) higher following malabsorptive procedures compared to obese controls and restrictive procedures, respectively, with moderate to high heterogeneity. Site-specific relative fracture risk (hip and wrist) was one- to two-folds higher post malabsorptive procedures compared to obese controls or restrictive procedures. The risks of any and of site-specific fracture were not increased following restrictive procedures compared to obese controls. Fracture risk seems to increase following malabsorptive bariatric surgeries, at a mean/median follow-up > 2 years. The risk is not increased with restrictive surgeries. The available evidence has several limitations. A prospective and rigorous long-term follow-up of patients following bariatric surgery is needed for a better assessment of their fracture risk with aging.

Bone Response to Weight Loss Following Bariatric Surgery

Obesity is a global health challenge that warrants effective treatments to avoid its multiple comorbidities. Bariatric surgery, a cornerstone treatment to control bodyweight excess and relieve the health-related burdens of obesity, can promote accelerated bone loss and affect skeletal strength, particularly after malabsorptive and mixed surgical procedures, and probably after restrictive surgeries. The increase in bone resorption markers occurs early and persist for up to 12 months or longer after bariatric surgery, while bone formation markers increase but to a lesser extent, suggesting a potential uncoupling process between resorption and formation. The skeletal response to bariatric surgery, as investigated by dual-energy X-ray absorptiometry (DXA), has shown significant loss in bone mineral density (BMD) at the hip with less consistent results for the lumbar spine. Supporting DXA studies, analyses by high-resolution peripheral quantitative computed tomography (HR-pQCT) showed lower cortical density and thickness, higher cortical porosity, and lower trabecular density and number for up to 5 years after bariatric surgery. These alterations translate into an increased risk of fall injury, which contributes to increase the fracture risk in patients who have been subjected to bariatric surgery procedures. As bone deterioration continues for years following bariatric surgery, the fracture risk does not seem to be dependent on acute weight loss but, rather, is a chronic condition with an increasing impact over time. Among the post-bariatric surgery mechanisms that have been claimed to act globally on bone health, there is evidence that micro- and macro-nutrient malabsorptive factors, mechanical unloading and changes in molecules partaking in the crosstalk between adipose tissue, bone and muscle may play a determining role. Given these circumstances, it is conceivable that bone health should be adequately investigated in candidates to bariatric surgery through bone-specific work-up and dedicated postsurgical follow-up. Specific protocols of nutrients supplementation, motor activity, structured rehabilitative programs and, when needed, targeted therapeutic strategies should be deemed as an integral part of post-bariatric surgery clinical support.

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.

Rates, Risks, and Time to Fracture in Patients Undergoing Laparoscopic Vertical Sleeve Gastrectomy versus Roux-en-Y Gastric Bypass

Objective

To assess the rates, risks, and time to fracture in patients undergoing laparoscopic vertical sleeve gastrectomy (VSG) versus those undergoing Roux-en-Y gastric bypass (RYGB).

Summary Background Data

Metabolic and bariatric surgery has been implicated in significant bone loss and may increase fracture risk. Preoperative patient characteristics that might impact fracture risk and the time to fractures have not been established. Furthermore, the patient characteristics that might impact fracture risk and the time to fractures by surgical approach are unknown.

Methods

This population-based retrospective cohort analysis used Humana claims data from January 1, 2007 to March 31, 2017, and included 4073 patients undergoing laparoscopic RYGB and VSG as a first surgical intervention for weight loss. The primary outcomes were the incidence of fractures (Humeral, Radial or Ulnar, Pelvic, Hip, and Vertebral) within 48 months after laparoscopic VSG versus RYGB and days to these fractures.

Results

An analysis of total fractures (odds ratio [OR] 0.53; 95% confidence interval [CI], 0.38-0.73), vertebral fractures (OR 0.61; 95% CI, 0.38-0.99), hip fractures (OR 0.36; 95% CI, 0.15-0.84), and humeral fractures (OR 0.44; 95% CI, 0.22-0.90) demonstrated a reduction in fracture risk in patients undergoing VSG versus RYGB. Furthermore, postmenopausal status was independently associated with increased odds of total fractures and hip fractures (OR 2.18; 95% CI, 1.06-4.50; OR 5.83; 95% CI, 1.16-29.27; respectively). Likewise, osteoporosis at the time of surgery was associated with increased odds of total fractures (OR 1.61; 95% CI, 1.09-2.37), vertebral fractures (OR 2.01; 95% CI, 1.19-3.39), and hip fractures (OR 2.38; 95% CI, 1.19-4.77). Except for a significantly decreased odds of vertebral fractures in osteoporotic patients undergoing VSG versus RYGB (OR 0.41; 95% CI, 0.18-0.95), osteoporotic or postmenopausal status at the time of surgery was not found to increase odds of fracture depending on surgical intervention. However, time to fracture (total) and for all site-specific fractures, except for pelvic fractures, was significantly reduced in postmenopausal women undergoing RYGB versus VSG. Time to fracture (total) and for all site-specific fractures except pelvic and radial or ulnar fractures was significantly reduced in osteoporotic patients undergoing RYGB versus VSG.

Conclusions and Relevance

Though bariatric surgery is associated with several health-related benefits, increased fracture risk is an important factor to discuss with patients undergoing bariatric surgery. Bariatric surgery strategy, RYGB versus VSG, carries a differential risk of fracture, with RYGB carrying a higher risk of fracture and decreased time to fracture. Furthermore, patients who are postmenopausal or osteoporotic at the time of surgery carry an increased risk of total fractures, independent of bariatric surgery strategy. Being mindful of patient-specific fracture risk after bariatric surgery may help anticipate, identify, and prevent fractures.

Fracture Risk After Bariatric Surgery: A Systematic Literature Review and Meta-Analysis

OBJECTIVE

Bariatric surgery has undeniable benefits for cardiovascular and metabolic health, but it can result in negative effects on mineral and bone metabolism. This study aimed to review the current data on fractures after the main types of bariatric surgery.

METHODS

Therefore, a systematic review was performed using the electronic literature available in the databases LILACS, CENTRAL, Web of Science, Embase, and PubMed/MEDLINE, with results until January 2021. Keywords were descriptors for bariatric surgery or bariatric medicine or bariatrics or gastroplasty and bone or bones or bone fractures, referenced in all words of the text in the study.

RESULTS

The meta-analysis of observational studies and interventional trials showed that the risk of any type of fracture was higher in the surgical group than in the nonsurgical group (relative risk [RR], 1.20 [95% confidence interval {CI}, 1.15-1.26; P < .00001; Phetero < 0.000001; I² = 94%], and RR, 1.16 [95% CI, 1.00-1.33; P = .04; Phetero = 0.27; I² = 23%], respectively). It is worth noting that the included interventional studies have a low rating on the risk of bias assessment scales. Compared with those who underwent restrictive procedures, subjects had an increased fracture risk after malabsorptive procedures (RR, 0.49 [95% CI, 0.40-0.61; P < .00001); Phetero = 0.96; I² = 0%).

CONCLUSION

We found that bariatric procedures are associated with an increased risk of fractures, especially the malabsorptive techniques.

Increased Fracture Risk After Bariatric Surgery: a Case-Controlled Study with a Long-Term Follow-Up

Purpose

Bariatric surgeries are common procedures due to the high prevalence of obesity. This study aimed to investigate whether bariatric surgery increases fracture risk.

Material and Methods

It was a case-controlled study. Patients who underwent bariatric surgery during 2011 and 2012 were matched for age (± 5 years) and gender to patients on medical weight management during the same period with a ratio of 1:2. The index date was defined as the date of bariatric surgery for both groups. The subject’s electronic medical records were reviewed retrospectively to identify fractures documented by radiology during January 2020.

Results

Randomly selected 403 cases were matched to 806 controls with a median age of 36.0 years (IQR 14.0) and 37.0 years (IQR 14.0), respectively. Seventy per cent of the cohort were females. Eighty per cent received sleeve gastrectomy, and the remaining (17%) underwent gastric bypass. The mean duration of follow-up was 8.6 years. The fracture rate was higher in the surgical group as compared to the controls (9.4% vs 3.5%) with a crude odds ratio of 2.71 (95% CI 1.69–4.36). The median duration for time to fracture was 4.17 years for the surgical group and 6.09 years for controls (p-value = 0.097). The most common site of fractures was feet, followed by hands. Apart from a few wrist fractures, there was no typical osteoporotic sites fracture.

Conclusion

Subjects who underwent bariatric procedures had more non-typical osteoporotic site fractures affecting mainly feet and hands, and fractures tend to occur earlier as compared to controls.

Graphical abstract

Understanding the Experience of Osteoporosis Risk in Bariatric Surgical Patients

Despite what is known about risk factors, preventive treatment, and increased prevalence of fragility fractures in post-bariatric surgical patients, little is known about how patient perspectives of osteoporosis risk inform their commitment to bone health. The purpose of this study was to examine the lived experience of osteoporosis risk in people who have had bariatric surgery. Interpretive phenomenology was used to explore osteoporosis from the perspectives of patients who have had bariatric surgery. Eligibility criteria included female, age older than 18 years, and able to understand and speak English. This research provided an understanding of the risk of osteoporosis from the constructed realities and experiences of those who have had bariatric surgery. Participants in this study incorrectly felt they had little to no risk for osteoporosis after bariatric surgery. Patients need to be aware of an increased risk for osteoporosis leading to the potential for fragility fractures after bariatric surgery; nurses are well positioned to enhance osteoporosis prevention efforts in this population through pre- and postoperative education.

Smoking in bariatric surgery: a systematic review

BACKGROUND

The prevalence of smoking among patients undergoing bariatric surgery has been reported to be as high as 40%. The effect of smoking in the perioperative period has been extensively studied for various surgical procedures, but limited data are available for bariatric surgery. The objective of this study is to review the existing literature to assess: (1) the impact of smoking on postoperative morbidity and mortality after bariatric surgery, (2) the relationship between smoking and weight loss after bariatric surgery, and (3) the efficacy of smoking cessation in the perioperative period among bariatric surgery patients.

METHODS

A comprehensive search of electronic databases including MEDLINE, EMBASE and the Cochrane Library from 1946 to February 2020 was performed to identify relevant articles. Following an initial screen of 940 titles and abstracts, 540 full articles were reviewed.

RESULTS

Forty-eight studies met criteria for analysis: five structured interviews, three longitudinal studies, thirty-two retrospective studies and eight prospective studies. Smoking within 1 year prior to bariatric surgery was found to be an independent risk factor for increased 30-day mortality and major postoperative complications, particularly wound and pulmonary complications. Smoking was significantly associated with long-term complications including marginal ulceration and bone fracture. Smoking has little to no effect on weight loss following bariatric surgery, with studies reporting at most a 3% increased percentage excess weight loss. Rates of smoking recidivism are high with studies reporting that up to 17% of patients continue to smoke postoperatively.

CONCLUSIONS

Although current best practice guidelines recommend only a minimum of 6 weeks of abstinence from smoking prior to bariatric surgery, the findings of this review suggest that smoking within 1 year prior to bariatric surgery is associated with significant postoperative morbidity. More investigation is needed on strategies to improve smoking cessation compliance among bariatric surgery patients in the perioperative period.

Long-term Bone Loss and Deterioration of Microarchitecture After Gastric Bypass in African American and Latina Women

CONTEXT

The prevalence of obesity is burgeoning among African American and Latina women; however, few studies investigating the skeletal effects of bariatric surgery have focused on these groups.

OBJECTIVE

To investigate long-term skeletal changes following Roux-en-Y gastric bypass (RYGB) in African American and Latina women.

DESIGN

Four-year prospective cohort study.

PATIENTS

African American and Latina women presenting for RYGB (n = 17, mean age 44, body mass index 44 kg/m2) were followed annually for 4 years postoperatively.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry (DXA) measured areal bone mineral density (aBMD) at the spine, hip, and forearm, and body composition. High-resolution peripheral quantitative computed tomography measured volumetric bone mineral density (vBMD) and microarchitecture. Individual trabecula segmentation-based morphological analysis assessed trabecular morphology and connectivity.

RESULTS

Baseline DXA Z-Scores were normal. Weight decreased ~30% at Year 1, then stabilized. Parathyroid hormone (PTH) increased by 50% and 25-hydroxyvitamin D was stable. By Year 4, aBMD had declined at all sites, most substantially in the hip. There was significant, progressive loss of cortical and trabecular vBMD, deterioration of microarchitecture, and increased cortical porosity at both the radius and tibia over 4 years. There was loss of trabecular plates, loss of axially aligned trabeculae, and decreased trabecular connectivity. Whole bone stiffness and failure load declined. Risk factors for bone loss included greater weight loss, rise in PTH, and older age.

CONCLUSIONS

African American and Latina women had substantial and progressive bone loss, deterioration of microarchitecture, and trabecular morphology following RYGB. Further studies are critical to understand the long-term skeletal consequences of bariatric surgery in this population.

Bariatric Surgery Decreases the Risk of Non-traffic Accident-Related Fractures in Patients with Obesity: Real-world Data from Taiwan

OBJECTIVES

The aim of this study is to investigate the impact of bariatric surgery on non-traffic accident-related fractures in patients with obesity.

METHODS

This retrospective cohort study was conducted using the Taiwan National Health Insurance Research Database. Patients aged 18 to 55 years with obesity diagnosis between 2003 and 2008 were enrolled and divided into two groups: non-surgical and bariatric surgery groups. Patients with endocrine bone disease and malignancy history were excluded. Healthy patients were also randomly selected from the database and assigned to the general population group. The development of fracture was the primary end point. All patients were followed until the end of 2013 or death, whichever came first.

RESULTS

After propensity score matching, 1322, 1322, and 4359 subjects were included in the bariatric surgery (BS), non-surgical (NS), and general population (GP) groups, respectively. Based on multivariate analysis, the risk of overall fractures is similar between the BS group (hazard ratio [HR] = 0.774, p = 0.164) and the NS group; nevertheless, the risk of overall fractures was higher in the BS group (HR = 2.210, p<0.001) than in the GP group. The BS group had a significantly lower risk of non-traffic accident-related fractures (HR = 0.542, p = 0.010) than the NS group but a higher risk of non-traffic accident-related fractures (HR = 1.693, p = 0.023) than the GP group.

CONCLUSIONS

Bariatric surgery may decrease the risk of non-traffic accident-related fractures; however, the risk remains higher in patients with obesity than in the general population.

Intersection of smoking, e-cigarette use, obesity, and metabolic and bariatric surgery: a systematic review of the current state of evidence

BACKGROUND

Millions of Americans qualify for metabolic and bariatric surgery (MBS) based on the proportion of the population with severe obesity. Simultaneously, the use of electronic nicotine/non-nicotine delivery systems (ENDS) has become epidemic.

OBJECTIVE

We conducted a timely systematic review to examine the impact of tobacco and ENDS use on post-operative health outcomes among MBS patients.

METHODS

PRISMA guidelines were used as the search framework. Keyword combinations of either "smoking," "tobacco," "e-cigarette," "vaping," or "ENDS" and "bariatric surgery," "RYGB," or "sleeve gastrectomy" were used as search terms in PUBMED, Science Direct, and EMBASE. Studies published in English between January 1990 and June 2020 were screened.

RESULTS

From the 3251 articles found, a total of 48 articles were included in the review. No articles described a relationship between ENDS and post-operative health outcomes in MBS patients. Seven studies reported smokers had greater post-MBS weight loss, six studies suggested no relationship between smoking and post-MBS weight loss, and one study reported smoking cessation pre-MBS was related to post-MBS weight gain. Perioperative use of tobacco is positively associated with several post-surgery complications and mortality in MBS patients.

CONCLUSIONS

Combustible tobacco use among MBS patients is significantly related to higher mortality risk and complication rates, but not weight loss. No data currently is available on the impact of ENDS use in these patients. With ENDS use at epidemic levels, it is imperative to determine any potential health effects among patients with severe obesity, and who complete MBS.

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.

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 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.

Risedronate to Prevent Bone Loss After Sleeve Gastrectomy: Study Design and Feasibility Report of a Pilot Randomized Controlled Trial

Mounting evidence implicates bariatric surgery as a cause of increased skeletal fragility and fracture risk. Bisphosphonate therapy reduces osteoporotic fracture risk and may be effective in minimizing bone loss associated with bariatric surgery. The main objective of this pilot randomized controlled trial (RCT; Clinical Trial No. NCT03411902) was to determine the feasibility of recruiting, treating, and following 24 older patients who had undergone sleeve gastrectomy in a 6 month RCT examining the efficacy of 150‐mg once‐monthly risedronate (versus placebo) in the prevention of surgical weight‐loss–associated bone loss. Feasibility was defined as: (i) >30% recruitment yield, (ii) >80% retention, (iii) >80% pills taken, (iv) <20% adverse events (AEs), and (v) >80% participant satisfaction. Study recruitment occurred over 17 months. Seventy participants were referred, with 24 randomized (34% yield) to risedronate (n = 11) or placebo (n = 13). Average age was 56 ± 7 years, 83% were female (63% postmenopausal), and 21% were black. The risedronate group had a higher baseline BMI than the placebo group (48.1 ± 7.2 versus 41.9 ± 3.8 kg/m²). The 10‐year fracture risk was low (6.0% major osteoporotic fracture, 0.4% hip fracture); however, three individuals (12.5%, all risedronate group) were osteopenic at baseline. Twenty‐one participants returned for 6‐month follow‐up testing (88% retention) with all (n = 3) loss to follow‐up occurring in the risedronate group. Average number of pills taken among completers was 5.9 ± 0.4 and 6.0 ± 0.0 in the risedronate and placebo groups, respectively (p = 0.21), with active participants taking >80% of allotted pills. Five AEs (3.7% AE rate) were reported; one definitely related, four not related, and none serious. All participants reported high satisfaction with participation in the study. Use of bisphosphonates as a novel therapeutic to preserve bone density in patients who had undergone a sleeve gastrectomy appears feasible and well‐tolerated. Knowledge gained from this pilot RCT will be used to inform the design of an appropriately powered trial.

Clinical Trial Registration

http://clinicaltrials.gov/show/NCT03411902. Weight Loss With Risedronate for Bone Health. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Gastric Bypass But Not Sleeve Gastrectomy Increases Risk of Major Osteoporotic Fracture: French Population-Based Cohort Study

The objective of this work was to investigate the risk of major osteoporotic fracture (MOF; hip, proximal humerus, wrist and distal forearm, and clinical spine) in bariatric surgery patients versus matched controls. Bariatric surgery is associated with an increase in fracture risk. However, it remains unclear whether the same degree of fracture risk is associated with sleeve gastrectomy, which has recently surpassed gastric bypass. Records from the French National Inpatient database were used from 2008 to 2018. Bariatric surgery patients, aged 40 to 65 years, with BMI ≥40 kg/m² , hospitalized between January 1, 2010 and December 31, 2014, were matched to one control (1:1) by age, sex, Charlson comorbidity index, year of inclusion, and class of obesity (40 to 49.9 kg/m² versus ≥50 kg/m² ). We performed a Cox regression analysis to assess the association between the risk of any MOF and, respectively, (i) bariatric surgery (yes/no) and (ii) type of surgical procedure (gastric bypass, gastric banding, vertical banded gastroplasty, and sleeve gastrectomy) versus no surgery. A total of 81,984 patients were included in the study (40,992 in the bariatric surgery group, and 40,992 matched controls). There were 585 MOFs in the surgical group (2.30 cases per 1000 patient-year [PY]) and 416 MOFs in the matched controls (1.93 cases per 1000 PY). The risk of MOF was significantly higher in the surgical group (hazard ratio [HR] 1.22; 95% CI, 1.08-1.39). We observed an increase in risk of MOF for gastric bypass only (HR 1.70; 95% CI, 1.46-1.98) compared with the matched controls. In patients aged 40 to 65 years, gastric bypass but not sleeve gastrectomy or the other procedures increased risk of major osteoporotic fractures. © 2020 American Society for Bone and Mineral Research.

Impact of sleeve gastrectomy on hip structural analysis in adolescents and young adults with obesity

BACKGROUND

Sleeve gastrectomy (SG), the most commonly performed metabolic and bariatric surgery, is associated with reductions in areal bone mineral density at multiple sites, and changes in bone structure at the distal radius and tibia without reductions in strength estimates at these peripheral sites. Data are lacking regarding effects on hip strength estimates.

OBJECTIVE

To evaluate effects of SG on measures of hip structural analysis in adolescents and young adults over 12 months using dual-energy x-ray absorptiometry.

SETTINGS

Translational and Clinical Research Center.

METHODS

We enrolled 48 youth 14- to 22-years old with moderate-to-severe obesity; 24 underwent SG and 24 controls were followed without surgery (18 females, 6 males in each group). Hip structure was assessed using dual-energy x-ray absorptiometry at baseline and 12 months. Analyses are adjusted for age, sex, race, and the baseline bone measure.

RESULTS

The SG group lost 25.9% weight versus .3% in controls. Compared with controls, SG had reductions in narrow neck, intertrochanteric and femoral shaft bone mineral density Z-scores (P ≤ .012). Furthermore, SG had greater reductions in narrow neck and intertrochanteric region (but not femoral shaft) cross-sectional area, cortical thickness, cross-sectional moment of inertia and section modulus, and increases in buckling ratio (P ≤ .039). Differences were attenuated after adjusting for 12-month body mass index change. At 12 months, differences were minimal after adjusting for age, sex, race, and weight.

CONCLUSIONS

Over 12 months, SG had negative effects at the narrow neck and intertrochanteric regions of the hip, but not the femoral shaft. Reduced body mass index may compensate for these deleterious effects on bone.

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.

Bone outcomes following sleeve gastrectomy in adolescents and young adults with obesity versus non-surgical controls

BACKGROUND

Sleeve gastrectomy is the most commonly performed weight loss surgery in adolescents with moderate-to-severe obesity. While studies in adults have reported on the deleterious effects of gastric bypass surgery on bone structure and strength estimates, data are lacking for the impact of sleeve gastrectomy on these measures in adolescents.

OBJECTIVE

To evaluate the impact of sleeve gastrectomy on bone outcomes in adolescents and young adults over 12 months using dual energy X-ray absorptiometry (DXA) and high resolution peripheral quantitative computed tomography (HRpQCT).

PARTICIPANTS AND METHODS

We enrolled 44 youth 14-22 years old with moderate to severe obesity; 22 underwent sleeve gastrectomy and 22 were followed without surgery (16 females and 6 males in each group). At baseline and 12 months, DXA was used to assess areal bone mineral density (aBMD), HRpQCT of the distal radius and tibia was performed to assess bone geometry, microarchitecture and volumetric BMD (vBMD), and finite element analysis to assess strength estimates (stiffness and failure load). These analyses were adjusted for age, sex, race and the bone measure at baseline. Fasting blood samples were assessed for calcium, phosphorus, and 25(OH) vitamin D (25OHD) levels.

RESULTS

Over 12-months, the surgical group lost 27.2% of body weight compared to 0.1% in the non-surgical (control) group. Groups did not differ for changes in 25OHD levels (p = 0.186). Compared to controls, the surgical group had reductions in femoral neck and total hip aBMD Z-scores (p ≤ 0.0006). At the distal tibia, compared to controls, the surgical group had reductions in cortical area and thickness and trabecular number, and increases in trabecular area and separation (p ≤ 0.026). At the distal radius, the surgical group had greater reductions in trabecular vBMD, than controls (p = 0.010). The surgical group had an increase in cortical vBMD at both sites (p ≤ 0.040), possibly from a decrease in cortical porosity (p ≤ 0.024). Most, but not all, differences were attenuated after adjusting for 12-month change in BMI. Groups did not differ for changes in strength estimates over time, except that increases in tibial stiffness were lower in the surgical group (p = 0.044) after adjusting for 12-month change in BMI.

CONCLUSIONS

Over 12 months, weight loss associated with sleeve gastrectomy in adolescents had negative effects on areal BMD and certain HRpQCT parameters. However, bone strength estimates remained stable, possibly because of a simultaneous decrease in cortical porosity and increase in cortical volumetric BMD. Additional research is necessary to determine the relative contribution(s) of weight loss and the metabolic effects of surgery on bone outcomes, and whether the observed effects on bone stabilize or progress over time.

Bone Health Following Bariatric Surgery: An Update

Obesity rates are increasing rapidly, and bariatric surgery is currently the most effective tool for weight loss. Recently, bariatric surgery induced bone loss has gained attention. Such detrimental effect on bone is multifactorial and causes may include nutrient deficiencies, gut and gonadal hormonal changes, mechanical unloading, loss of lean mass, increased bone marrow fat, and increased risk of fall. This review describes the available evidence on bone loss and fracture risk following bariatric surgery and summarizes the guidelines on the topic. Increased bone resorption starts early postsurgery, and bone markers peak at 1-2 yr. Across studies, the drop in areal bone mineral density is inconsistent at the lumbar spine, while a 2%-5% drop at 6 mo and a 6%-10.5% at 9-12 mo are observed at the total hip. Conversely, studies using quantitative CT showed a 6%-7% decrease in volumetric bone mineral density at the lumbar spine at 6-12 mo postsurgery. These studies also report significant bone loss at the radius and tibia, in addition to alteration in bone microarchitecture. Fracture risk increases 2 yr after surgery, more so following malabsorptive procedures. Fractures were reported at axial, weight bearing sites and at appendicular sites. The available evidence is very heterogeneous, and mostly derived from studies on Roux-en-y gastric bypass in premenopausal women. Data on restrictive procedures is scarce. Our findings suggest that the early postoperative phase represents the "golden window" to intervene and promote bone health. More research is needed to determine the effect of different bariatric procedures on bone, to identify optimal interventions to prevent bone loss and to characterize high risk individuals who should be targeted.

Comparative risk of fracture for bariatric procedures in patients with obesity: A systematic review and Bayesian network meta-analysis

OBJECTIVE

Bariatric surgery (malabsorptive [i.e., biliopancreatic diversion, BPD], restrictive [i.e., sleeve gastrectomy, SG; adjustable gastric banding, AGB] and mixed [i.e., gastric bypass, GB] procedures) has been reported to be associated with an increased risk of fracture; however, which procedure poses the greatest risk of fracture is still controversial. The aim of the current meta-analysis was to investigate the degree of fracture risk after different bariatric procedures.

MATERIAL AND METHODS

Electronic databases, including Medline/PubMed, EMBASE and Cochrane library, were systematically searched from inception to July 11, 2019 with no language restrictions to retrieve randomized controlled trials (RCTs) or cohort studies evaluating the impact of any kind of bariatric surgery on postoperative fractures in patients with obesity. Pairwise meta-analysis and Bayesian network meta-analysis were performed to pool the outcome estimates of interest, including fracture incidence and fracture risk. The values of the surface under the cumulative ranking (SUCRA) probability for fracture risk were calculated and sorted according to the different surgical procedures.

RESULTS

A total of twelve studies published between 2010 and 2019, comprising 159,916 participants with obesity were identified for the analysis. The incidence of fracture increased from 3% (95% confidence interval [CI] 2-4%) in patients with non-surgical intervention (drug treatment, alteration in life style and diet control) to 5% (95% CI 4-7%) in those who had undergone bariatric surgery (pooled relative risk [RR] = 1.41 95% CI: 1.22-1.63). Network meta-analysis revealed that based on the SUCRA ranking of the different surgical procedures, the malabsorptive procedure had the highest possibility of increased fracture risk in patients with obesity (74.75%), followed by the mixed procedures (73.85%), nonsurgical intervention (43.55%) and the restrictive procedure (7.85%); for different surgery types. The BPD group had the highest possibility of increased fracture risk (99.49%), followed by the GB (74.92%), nonsurgical intervention (44.49%), AGB (26.64%) and SG (4.45%) groups.

CONCLUSIONS

Significant differences exist among different bariatric surgeries impacting on fracture risk. The malabsorptive and mixed procedures, but not the restrictive procedure, increase the postoperative risk of fracture. Considering the weight-reduction effects and fracture risk, the sleeve gastrectomy procedure may be the best choice for patients with obesity, especially those who are susceptible to osteoporosis.

The Impact of Roux-en-Y Gastric Bypass on Bone Remodeling Expressed by the P1NP/βCTX Ratio: a Single-Center Prospective Cohort Study

BACKGROUND

Bariatric surgery seems to decrease bone mineral density and increase the risk of fatigue fractures. P1NP (bone formation) and βCTX (bone resorption) were recently validated as reference bone turnover markers (BTM).

OBJECTIVE

To assess changes in bone remodeling in severely obese patients undergoing Roux-en-Y gastric bypass (RYGB) by using a new composite biomarker, the P1NP/βCTX ratio.

METHODS

We prospectively collected blood samples preoperatively, at 1 month and at 1 year from 114 consecutive RYGB patients from 12/2012 to 04/2014. Repeated measures ANOVA and multiple regression were used for data analysis. Cumulative incidence of fractures was assessed in 06/2018.

RESULTS

The P1NP/βCTX ratio decreased significantly (P < 0.001) from baseline to 1 month and 1 year (180 ± 6.6, 110 ± 4.1, and 132 ± 5.4). The 1-year P1NP/βCTX ratio did not correlate with BMI or ΔBMI, but inversely correlated with age (r = - 0.23, P = 0.014) and with hsCRP (r = - 0.26, P = 0.009), even after adjustment for age, sex, BMI, and lifestyle, and linearly correlated with albumin (r = 0.2, P = 0.037). At baseline, none of these correlations were detectable. Serum for all time-points was available from > 94% of the patients. At a median follow-up of 4.7 years, 8 patients (7.3%) had a bone fracture, all of them traumatic.

CONCLUSION

Following RYGB, bone remodeling increases, with a shift toward degradation. This effect seems to be weight-loss independent and shows a correlation with age, with the level of systemic inflammation, and with nutritional state. The risk of fractures should be assessed systematically in bariatric patients and measures of prevention should be improved accordingly.

Vitamin D, genetics, and bone mineral density during weight loss

PURPOSE OF REVIEW

The current review is to summarize the recent progress in the research of the relation between vitamin D and bone mineral density (BMD) during weight-loss interventions, and describe how genetic factors interact with weight-loss interventions on changes in bone health.

RECENT FINDINGS

Obesity has shown to be a protective factor for bone health, whereas the relation between weight loss and BMD has yet to be well established. Although beneficial on a variety of metabolic outcomes, weight-loss interventions, such as dietary modifications and surgical treatment, showed adverse effects on bone health in some studies. Despite the biological plausibility for a role of vitamin D in promoting bone health, current evidence does not consistently support the connection between changes in circulating vitamin D levels and BMD during weight loss, partly because of insufficient vitamin D levels during weight loss. Genome-wide association studies have identified genetic variants related to the blood levels of vitamin D; and emerging evidence suggests that dietary intakes may modify the relationship between genetically determined circulating vitamin D levels and change in BMD in response to weight-loss diets.

SUMMARY

The relations of changes in circulating vitamin D levels with bone health during weight-loss interventions remain to be established, and the role of genetic factors would be considered in future investigations.

Longitudinal 5-Year Evaluation of Bone Density and Microarchitecture After Roux-en-Y Gastric Bypass Surgery

CONTEXT

Bone health declines in the initial years after Roux-en-Y gastric bypass (RYGB), but long-term skeletal effects are unclear.

OBJECTIVE

To document longitudinal changes in bone mineral density (BMD) and microarchitecture 5 years after RYGB.

DESIGN, SETTING, AND PARTICIPANTS

Prospective 5-year observational study of 21 adults with severe obesity receiving RYGB at an academic medical center.

MAIN OUTCOME MEASURES

Spine and hip areal BMD were measured by dual-energy X-ray absorptiometry, and trabecular volumetric BMD (vBMD) of the spine was assessed by quantitative CT (QCT). We measured vBMD and microarchitecture of the distal radius and tibia by high-resolution peripheral QCT in a subset of subjects. Serum type I collagen C-terminal telopeptide (CTX) and procollagen type I N-terminal propeptide (P1NP) were also measured.

RESULTS

Areal BMD declined by -7.8% ± 7.6% at the spine and -15.3% ± 6.3% at the total hip by 5 years after RYGB (P ≤ 0.001), although the rate of bone loss slowed in later years. Trabecular spine vBMD decreased by -12.1% ± 12.3% by 5 years (P ≤ 0.001). At peripheral sites, vBMD continued to decrease steadily throughout 5 years, with parallel declines in cortical and trabecular microarchitecture, leading to decreases in estimated failure load of -20% and -13% at the radius and tibia, respectively (P < 0.001). Five years after RYGB, CTX and P1NP were 150% and 34% above baseline (P < 0.001 and P = 0.017, respectively).

CONCLUSIONS

Sustained high-turnover bone loss and bone microarchitectural deterioration occur in the 5 years after RYGB. Adults receiving RYGB warrant assessment of bone health.