Effects of vertical-banded gastroplasty on bone and mineral metabolism in obese patients

Effect of bariatric surgery on endogenous sex hormones and sex hormone-binding globulin levels: a systematic review and meta-analysis

BACKGROUND

Most studies have shown beneficial effect of bariatric surgery (BS) on serum levels of sex hormones.

OBJECTIVE

A systematic review and meta-analysis was conducted to examine the magnitude of possible changes in levels of sex hormones following BS.

SETTINGS

Electronic databases were searched, including PubMed, Scopus, Web of Science, and Embase, for relevant studies.

METHODS

The heterogeneity of the studies was examined by χ² tests and the degree of heterogeneity was estimated using I² statistic.

RESULTS

The results of pooled analyses revealed that BS caused a significant increase in luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone (TT), and sex hormone binding globulin (SHBG) levels and conversely, decreased dehydroepiandrosterone (DHEA) and estradiol (E2) levels in males. For females, BS significantly increased LH, FSH, and SHBG levels and conversely, decreased androstenedione (AE), E2 and TT levels. Additionally, the level of progesterone (P), prolactin (PRL), free testosterone (FT) and dehydroepiandrosterone sulfate (DHEA-S) showed no significant changes in patients who had undergone BS.

CONCLUSION

BS changed most sex hormones levels including LH, FSH, TT, SHBG, AE, DHEA, and E2. It seems that BS is able to exert substantial impacts on sex hormones levels and as well as sexual function, however, larger, and more precise trials are required to specifically focus on these claims.

Bone mineral density and body composition after laparoscopic sleeve gastrectomy in men: A short-term longitudinal study

INTRODUCTION

Longitudinal changes in bone and body composition occurring in obese men after laparoscopic sleeve gastrectomy (LSG) has been evaluated.

METHODS

In short-term longitudinal study, 25 obese men in mean baseline age 44.8 ± 10.9 years and mean body mass index (BMI) 43.3 ± 4.4 kg/m(2)were assessed after undergoing LSG for obesity. Bone mineral density (BMD) (spine, femoral neck [FN], total hip [TH], and total body [TB]) and body composition (TB bone mineral content [BMC], fat, % of fat, lean, lean BMC, total mass) were assessed at baseline, and after three and six months.

RESULTS

Mean body measurements, including weight, BMI, waist and hips, decreased significantly over the study period (p < 0.0001). FN BMD (p < 0.01) and TH BMD (p < 0.001) decreased, and spine BMD increased significantly (p < 0.001). TB BMD did not change. Weight decreased by 21.3 ± 7.3%, BMI by 21.2 ± 7.3%, FN BMD by 3.32 ± 6.35%, TH BMD by 3.51 ± 3.95% whereas spine BMD increased by 2.89 ± 5.1%. TB BMC increased by 2.4 ± 4.62%; all other variables relating to body composition decreased: fat by 33.0 ± 9.6%, lean mass by 12.8 ± 6.1%, lean BMC by 12.3 ± 5.9%, total mass by 20.1 ± 6.4%, and % fat by 15.8 ± 7.2%.

CONCLUSIONS

After LSG, body size and variables related to body composition (except for TB BMC) decreased with an accompanying decrease in FN BMD in the men in this study. Spine BMD increased, and TB BMD did not change.

Gastric Cancer in the Excluded Stomach 10 Years after Gastric Bypass

According to the Brazilian health authorities, around 2,000 new cases of gastric cancer emerge in Brazil per year (Instituto Nacional de Câncer José Alencar Gomes da Silva, 2014). Indeed, gastric cancer constitutes the second most common cause of cancer-related mortality worldwide and 95% of such malignancies are adenocarcinomas (De Roover et al., 2006, and Clark et al., 2006). Roux-en-Y gastric bypass (RYGB) is a procedure frequently employed in bariatric surgery but restricted access to the excluded stomach means that discovery of gastric lesions is difficult, and diagnosis and treatment may be delayed. We report herein a case of gastric adenocarcinoma in the excluded stomach of a patient submitted to RYGB with the purpose of illustrating the difficulty of diagnosing and treating this rare condition.

Skeletal effects of bariatric surgery: examining bone loss, potential mechanisms and clinical relevance

Bariatric surgery is the most effective therapeutic approach to morbid obesity, resulting in substantial weight loss and improved cardiometabolic profiles; however, a growing body of evidence suggests that bariatric procedures increase both skeletal fragility and the risk of related future fracture secondary to excessive bone loss. Prospective evidence shows that areal bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DXA) declines by as much as 14% in the proximal femoral regions, including the femoral neck and total hip, 12 months postoperatively. Lumbar spine areal BMD outcomes show greater 12-month postoperative variability across surgical procedures (-8 to +6%) and contrast with no change in volumetric BMD outcomes measured by quantitative computed tomography. Diminished mechanical loading, micronutrient deficiency and malabsorption, along with neurohormonal alterations, offer plausible underlying mechanisms to explain these observed post-bariatric bone changes, but most remain largely unsubstantiated in this population. Importantly, DXA-based skeletal imaging may have limited utility in accurately detecting bone change in people undergoing bariatric surgery; partly because excessive tissue overlying bone increases the variability of areal BMD outcomes. Moreover, a paucity of fracture and osteoporosis incidence data raises questions about whether marked post-bariatric surgery bone loss is clinically relevant or a functional adaptation to skeletal unloading. Future studies that use technology which is able to accurately capture the site-specific volumetric BMD and bone architectural changes that underpin bone strength in people undergoing bariatric surgery, that consider mechanical load, and that better quantify long-term fracture and osteoporosis incidence are necessary to understand the actual skeletal effects of bariatric surgery.

Effect of bariatric surgery on bone mineral density: comparison of gastric bypass and sleeve gastrectomy

The aim of our study was to compare bone mineral density (BMD) a year after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) in age- and body mass index-matched women. In 33 morbidly obese women undergoing RYGB and 33 undergoing SG, plasma determinations of calcium, parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH) D3), and insulin-like growth factor-I (IGF-I) were made prior to and at 12 months after surgery. Dual-energy X-ray absorptiometry was performed in all patients 1 year after surgery. BMD at the femoral neck and the lumbar spine 1 year after surgery was similar in women undergoing RYGB and SG (1.01 ± 0.116 vs. 1.01 ± 0.122 g/cm(2), p = 0.993; 1.05 ± 0.116 vs. 1.08 ± 0.123 g/cm(2), p = 0.384). The percentage of patients with osteopenia and osteoporosis was not different between groups. In the linear regression analysis, age (β = -0.628, p = 0.034) and lean mass 12 months after surgery (β = 0.424, p = 0.021) were found to be the main determinants of femoral neck BMD. Age (β = -0.765, p = 0.025), menopause (β = -0.898, p = 0.033), and lean mass (β = 0.615, p = 0.023) were determinants of BMD at the lumbar spine. No influence was found between low bone mass and type of surgery, plasma PTH, 25(OH) D3, or IGF-I. The effect of RYGB and SG on BMD was comparable a year after surgery. Menopausal women were at a higher risk of having low bone mass, but the presence of osteoporosis was uncommon.

Bone metabolism after bariatric surgery

Bariatric surgery is a popular and effective treatment for severe obesity but may have negative effects on the skeleton. This review summarizes changes in bone density and bone metabolism from animal and clinical studies of bariatric surgery, with specific attention to Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), and sleeve gastrectomy (SG). Skeletal imaging artifacts from obesity and weight loss are also considered. Despite challenges in bone density imaging, the preponderance of evidence suggests that bariatric surgery procedures have negative skeletal effects that persist beyond the first year of surgery, and that these effects vary by surgical type. The long-term clinical implications and current clinical recommendations are presented. Further study is required to determine mechanisms of bone loss after bariatric surgery. Although early studies focused on calcium/vitamin D metabolism and mechanical unloading of the skeleton, it seems likely that surgically induced changes in the hormonal and metabolic profile may be responsible for the skeletal phenotypes observed after bariatric surgery.

Bone loss after bariatric surgery: causes, consequences, and management

Bariatric surgery is an effective and increasingly common treatment for severe obesity and its many comorbidities. The side-effects of bariatric surgery can include detrimental effects on bone and mineral metabolism. Bone disease in patients who have had bariatric surgery is affected by preoperative abnormalities in bone and mineral metabolism related to severe obesity. Changes that arise after bariatric surgery are specific to procedure type: the most pronounced abnormalities in calciotropic hormones and bone loss are noted after procedures that result in the most malabsorption. The most consistent site for bone loss after all bariatric procedures is at the hip. There are limitations of dual-energy x-ray absorptiometry technology in this population, including artefact introduced by adipose tissue itself. Bone loss after bariatric surgery is probably multifactorial. Proposed mechanisms include skeletal unloading, abnormalities in calciotropic hormones, and changes in gut hormones. Few data for fracture risk in the bariatric population are available, and this is a crucial area for additional research. Treatment should be geared toward correction of nutritional deficiencies and study of bone mineral density in high-risk patients. We explore the skeletal response to bariatric surgery, potential mechanisms for changes, and strategies for management.

Bone mineral changes in spine and proximal femur in individual obese women after laparoscopic sleeve gastrectomy: a short-term study

BACKGROUND

The aim of the study was to establish longitudinal bone changes in obese women after laparoscopic sleeve gastrectomy (LSG).

METHODS

Twenty-nine women at baseline mean age of 40.41 ± 9.26 years and with mean body mass index (BMI) of 43.07 ± 4.99 kg/m(2) were included in a 6-month study. Skeletal status at hip [femoral neck (FN) and total hip (TH)] and spine was assessed at baseline, as well as in 3 and 6 months after surgery. Body size was measured at baseline and follow-up (weight, height, BMI, and waist).

RESULTS

Baseline body weight was 117.5 ± 18.4 kg. The mean body weight and BMI decreased by 17.9 % during the first 3 months after surgery to obtain 28.4 % after 6 months. At 6 months, BMD decreased significantly for spine by 1.24 %, FN 6.99 %, and TH 5.18 %. The changes after 3 months in individual subjects showed that, in the majority of subjects, FN and TH BMD decreased significantly (in 52 % and 69 % of subjects, respectively), and in 24 % loss of BMD was found at the spine. After 6 months, the corresponding, significant decreases in individual subjects were found in 72 %, 86 %, and 38 % of woman, respectively. Those with a significant loss of FN BMD tended to lose more weight (30 ± 9.47 versus 23.25 ± 6.08 kg, p = 0.061) than others; women with a significant decrease of FN BMD lost more weight than those with no such decrease (30.43 ± 8.07 versus 15 ± 1.91 kg).

CONCLUSION

LSG proved efficient for body weight reduction, however, with a parallel decline in bone mineral density.

Risk of fracture after bariatric surgery in the United Kingdom: population based, retrospective cohort study

OBJECTIVES

To estimate fracture risk in patients receiving bariatric surgery versus matched controls.

DESIGN

Population based, retrospective cohort study.

SETTING

Use of records from the United Kingdom General Practice Research Database, now known as the Clinical Practice Research Datalink (from January 1987 to December 2010).

PARTICIPANTS

Patients with a body mass index of at least 30, with a record of bariatric surgery (n=2079), and matched controls without a record (n=10,442). Each bariatric surgery patient was matched to up to six controls by age, sex, practice, year, and body mass index. Patients were followed from the date of bariatric surgery for the occurrence of any fracture. We used time dependent Cox regression to calculate relative rates of fracture, adjusted for disease and previous drug treatment, and time-interaction terms to evaluate fracture timing patterns.

MAIN OUTCOME MEASURE

Relative rates of any, osteoporotic, and non-osteoporotic fractures.

RESULTS

Mean follow-up time was 2.2 years. Overall, there was no significantly increased risk of fracture in patients who underwent bariatric surgery, compared with controls (8.8 v 8.2 per 1000 person years; adjusted relative risk 0.89, 95% confidence interval 0.60 to 1.33). Bariatric surgery also did not affect risk of osteoporotic and non-osteoporotic fractures. However, we saw a trend towards an increased fracture risk after three to five years following surgery, as well as in patients who had a greater decrease in body mass index after surgery, but this was not significant.

CONCLUSION

Bariatric surgery does not have a significant effect on the risk of fracture. For the first few years after surgery, these results are reassuring for patients undergoing such operations, but do not exclude a more protracted adverse influence on skeletal health in the longer term.

Bariatric surgery and bone disease: from clinical perspective to molecular insights

The use of bariatric surgery for the treatment of morbid obesity has increased annually for the last decade. Although many studies have demonstrated the efficacy and durability of bariatric surgery for weight loss, there are limited data regarding long-term side effects of these procedures. Recently, there has been an increased focus on the impact of bariatric surgery on bone metabolism. Bariatric surgery utilizes one or more of three mechanisms of action resulting in sustained weight loss. These include restriction (gastric banding, vertical banded gastroplasty and sleeve gastrectomy), malabsorption surgery with or without associated restriction (Roux en Y gastric bypass, duodenal switch, biliopancreatic diversion and jejunoileal bypass) and changes in gut-derived hormones that control energy metabolism also referred to as neuro-hormonal control of energy metabolism (Roux en Y gastric bypass, duodenal switch, biliopancreatic diversion, jejunoileal bypass, surgical procedures as above and gastric sleeve). Weight reduction has been associated with increased bone resorption but the mechanisms behind this have not yet been fully elucidated. Each of the mechanisms of action of bariatric surgery (restriction, malabsorption, neuro-hormonal control of energy metabolism) may uniquely affect bone resorption. In this paper we will review the current state of knowledge regarding the relationship between bariatric surgery and bone metabolism with emphasis on possible mechanisms of action such as malnutrition, hormonal interactions and mechanical unloading of the skeleton. Further, we suggest a future research agenda.

Examining the link between bariatric surgery, bone loss, and osteoporosis: a review of bone density studies

As the popularity of bariatric surgery to treat morbid obesity has risen, so has a concern of increased skeletal fragility secondary to accelerated bone loss following bariatric procedures. We reviewed cross-sectional and prospective literature reporting bone density outcomes following bariatric surgical treatment for morbid obesity. Prospective research provides evidence of hip and lumbar spine areal bone mineral density (aBMD) reductions primarily in women despite calcium and vitamin D supplementation. Femoral neck aBMD declines of 9-11% and lumbar spine aBMD reductions up to 8% were observed at the first post-operative year following malabsorptive procedures. Mean T- and Z-scores up to 25 years following surgery remained within normal and healthy ranges. Of those studies reporting development of osteoporosis following gastric bypass, one woman became osteoporotic after 1 year. Despite observed bone loss in the hip region post-surgery, data do not conclusively support increased incidence of osteoporosis or increased fracture risk in post-bariatric patients. However, given the limitations of dual energy X-ray absorptiometry technology in this population and the relative lack of long-term prospective studies that include control populations, further research is needed to provide conclusive evidence regarding fracture outcomes in this population.

Serum leptin, parathyroid hormone, 1,25-dihydroxyvitamin D, fibroblast growth factor 23, bone alkaline phosphatase, and sclerostin relationships in obesity

BACKGROUND

Obesity is associated with hyperparathyroidism and increased bone mass and turnover, but their pathogeneses are unclear.

AIMS

Our aim was to determine in obesity interrelationships among serum levels of leptin, the mineral-regulating hormones, bone turnover markers, and sclerostin.

METHODS

This case-control study was performed in 20 women having bariatric surgery and 20 control women matched for race and age. Anthropometrics and fasting serum biochemistries were measured in controls and in bariatric patients the morning of surgery.

RESULTS

Body mass index (48.9 vs. 25.4 kg/m(2)), weight (128.6 vs. 71.9 kg), serum leptin (74.6 vs. 25.2 ng/ml), PTH (44.5 vs. 28.8 pg/ml), fibroblast growth factor 23 (FGF23) (42.4 vs. 25.9 pg/ml), and bone alkaline phosphatase (BAP) (25.8 vs. 17.5 U/liter) were higher, but height (162.3 vs. 167.7 cm) and 1,25-dihydroxyvitamin D (1,25D) (39.2 vs. 48.7 pg/ml) were lower in bariatric surgery patients than controls. There was no difference in serum sclerostin, amino-terminal collagen cross-links, 25-hydroxyvitamin D (25D), calcium, phosphate, and creatinine between groups. In the combined sample, leptin was positively related to PTH, FGF23, and BAP but not to 1,25D or sclerostin. Multiple regression analysis demonstrated that PTH was predicted by leptin and Ca (R(2) = 0.39); 1,25D by 25D, FGF23, and phosphate (R(2) = 0.43); FGF23 by leptin and 1,25D (R(2) = 0.27); BAP by leptin, PTH, and Ca (R(2) = 0.39); and sclerostin by leptin and PTH (R(2) = 0.20).

CONCLUSIONS

Women having bariatric surgery had higher leptin, PTH, FGF23, and BAP and lower 1,25D than controls. Leptin predicted the serum levels of PTH, 1,25D, and FGF23, the mineral-regulating hormones, and BAP, a bone formation marker, in women with body mass index ranging from 13.9-65.8 kg/m(2). The results suggest that leptin has an endocrine or paracrine effect on PTH and FGF23 production and that PTH may be one of the signals in obesity that leads to increased bone mass.

[Bone mass loss after sleeve gastrectomy: a prospective comparative study with gastric bypass]

INTRODUCTION

Bariatric surgery is the most effective option for the treatment of patients with a high risk of complications due to their obesity. However, it brings about a series of changes in calcium and vitamin D metabolism and an increase in resorption which lead to a loss of bone mass.

AIM

The objective of this study is to compare sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) as regards loss of bone mass using bone densitometry and bone remodelling markers.

PATIENTS AND METHODS

Fifteen women with morbid obesity were included, 8 by SG and 7 by RYGB, with a mean age of 47.8+/-9 and mean body mass index 43.3+/-3.4. Bone mass measurements were made on the lumbar spine, femur and distal radius, and the bone remodelling markers N-telopeptide (NTx) and bone alkaline phosphatase (BALP), as well as vitamin D levels before and 12 months after surgery.

RESULTS

A significant bone mass loss was observed was observed with SG and RYGB, in the lumbar spine and hip, whilst no differences were observed in the radial. The percentage bone mass loss was less in the column and femur after SG than with RYGB, although it did not reach statistical significance, 4.6%+/-4.4 (mean+/-SD) and 6.3%+/-5.4 (mean+/-SD), respectively. At 12 months the Ntx increased for both types of surgery, and the BAP was only increased for SG.

CONCLUSION

SG causes less, although not significant, bone mass loss compared to RYGB.

Bariatric surgery and bone metabolism: a systematic review

Few studies have demonstrated the risk of metabolic bone disease and a reduction in bone mineral density (BMD) after bariatric surgery. A systematic review was conducted of case-control and cohort studies with the aim of evaluating the relationship between bariatric surgery and bone metabolism. The search was undertaken in MedLine, covering the period from January 1997 to August 2009, using the keywords: "bariatric surgery" AND "osteoporosis", "fracture", "bone diseases", "metabolic". Six studies were included, comprising four cohort and two case-control studies. Three studies evaluated bone metabolism and BMD, and the other evaluated bone metabolism only. Based on this review, bariatric surgery is associated with alterations in bone metabolism, loss of bone mass and an increased risk of fracture. However, the maximum evaluation period covered by these studies was two years after surgery, hence the need to undertake further studies of longer duration in order to achieve a more thorough understanding of this association.

Evaluation of bone disease in morbidly obese women after gastric bypass and risk factors implicated in bone loss

BACKGROUND

In patients undergoing gastric bypass, massive weight loss and impairment of calcium intake and absorption in the duodenum and proximal jejunum may increase the risk of bone mass loss and fractures. However, few data are available regarding the impact of this surgery on the skeleton. The aim of our study was to examine the skeletal changes in a cohort of morbidly obese Caucasian women during the first year after gastric bypass and to analyse the factors implicated in the development of bone loss.

METHODS

Sixty-two morbidly obese white women aged 45.3 +/- 8.9 years were studied. Anthropometric measurements, bone mineral density (BMD) screening using dual-energy X- ray absorptiometry and plasma determinations of calcium, phosphorus, parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH) D(3)] and insulin-like growth factor-I (IGF-I) were made prior to and 12 months after surgery.

RESULTS

A year after surgery, BMD significantly decreased at the femoral neck (10.2 +/- 5.7%) and at the lumbar spine (3.2 +/- 4.4%). In the follow-up, 16.1% of women had osteopenia at the femoral neck and 19.3% at the lumbar spine, and 1.6% developed osteoporosis at the lumbar spine. Patients with bone disease were significantly older; the percentage of women with menopause was greater in this group and had lower initial and final values of lean mass. However, no differences in body mass index, weight loss, fat mass, calcium, PTH, 25(OH) D(3) or IGF-I values were found between groups. In the logistic regression analysis, lean mass 12 months after surgery and menopause were found to be the main determinants of osteopenia after adjusting for age with odds ratios of 0.82 and 9.13, respectively.

CONCLUSIONS

There is a significant BMD loss at the femoral neck and lumbar spine a year after gastric bypass. Menopausal patients and those with greater lean mass loss are at greater risk and, consequently, should be closely followed up with periodic densitometries.

Nutritional deficiencies after bariatric surgery

A current review of nutritional complications following bariatric procedures is presented, focusing on the most common and clinically important deficiencies. A brief outline of nutritional supplementation protocol is presented, highlighting the need for a standardized, national or international set of guidelines for pre- and postoperative nutritional screening and appropriate supplementation.

Mineral metabolism in obese patients following vertical banded gastroplasty

BACKGROUND

Bone disease has been described in patients after surgical treatment for obesity, but few studies have dealt with the impact of vertical banded gastroplasty on mineral metabolism. We have examined bone mineral metabolism in morbidly obese patients before and after 3 months after vertical banded gastroplasty without vitamin D supplementation.

METHODS

Sixteen morbidly obese patients (14 women, 2 men) with a mean (+/-SD) age of 38 +/- 9 years and a body mass index (BMI) of 47.1 +/- 8.1 kg/m2 were studied. No vitamin D supplementation was given. Body weight, fat mass, calcium, 25OHD, iPTH, bone remodeling markers, and leptin levels were measured at baseline and after weight loss.

RESULTS

Mean weight loss was 28 +/- 11 kg; BMI and body fat mass decreased by 20 and 35%, respectively. Bone resorption markers and albumin-corrected serum calcium increased after operation, whereas iPTH fell. Serum 25OHD levels rose. Leptin levels decreased. Serum iPTH was positively correlated with weight, BMI, and fat mass before operation (p < 0.05), and its decline after weight reduction was negatively associated with the increase in bone resorption markers (p < 0.01). Leptin concentration was correlated with BMI and body fat mass (p < 0.05) both before and after surgery.

CONCLUSIONS

Weight reduction obtained in morbidly obese subjects 3 months after vertical banded gastroplasty increases bone turnover markers and decreases PTH secretion. Serum 25OHD levels rose. Therefore, no reasons for a metabolic bone disease related to hypovitaminosis D were readily apparent. However, an increase in bone turnover, which is generally regarded as a potential risk factor for osteoporosis, was observed. Further work is needed to clarify the importance of this turnover increase in the long run.

Effects of weight loss on bone status after bariatric surgery: association between adipokines and bone markers

BACKGROUND

The prevalence of overweight and obesity is increasing dramatically worldwide. As a consequence, bariatric surgery for morbid obesity is in constant development. Although bariatric surgery has proven its efficiency at achieving weight loss and correcting comorbidities, it may cause vitamin deficiencies and subsequent complications. The goal of this review is to assess the impact of obesity surgery on bone metabolism and to analyze the underlying mechanisms and relationships with adipokines. Our review focuses on gastric banding, vertical banded gastroplasty, and gastric bypass.

METHODS

The articles were located via PubMed database, using the key words "bariatric surgery," "weight loss," "bone loss," and "bone metabolism" and published until May 2006.

RESULTS

Five main studies were reviewed concerning gastric banding and six concerning Roux-en-Y gastric bypass. An early increase in bone markers (formation and resorption) is constantly found, prevailing on bone resorption, and resulting in early bone loss.

CONCLUSION

According to the few studies available, bone loss frequently occurs after bariatric surgery and particularly in a more pronounced way after gastric bypass, but its clinical significance is still under discussion. In addition, the physiopathology of these changes remains unclear, but could implicate adipokines such as leptin and adiponectin.

Bone loss. An emerging problem following obesity surgery

The incidence of obesity worldwide has increased markedly in the past 2 decades, with estimates of increases of 50% in the United States alone. Research indicates that weight loss produced by diet alone is not sustained and that 75% of dieters regain most of the weight lost within 1 year and 90% within 2 years. Morbid obesity is associated with comorbid conditions, including heart disease, hypertension, diabetes, mechanical arthropathy, sleep apnea, and numerous other serious disorders and a shortened life expectancy. Because of limited success with medical management, surgical treatment of morbid obesity has been used increasingly, especially with the development of laparoscopic procedures, including Roux-en-Y gastric bypass (RYGB). RYGB is associated with low surgical mortality, marked decreased food intake, and significant, sustained weight loss. However, in this emerging, unique population there is growing appreciation that these procedures may be associated with the development of bone loss and skeletal fragility because of altered nutrient metabolism. Despite the threat of skeletal fragility and fracture, there is limited data addressing the effects of bariatric surgery on bone metabolism and bone loss.

Parathyroid hormone and bone marker levels in patients with morbid obesity before and after biliopancreatic diversion

BACKGROUND

Scopinaro biliopancreatic diversion (BPD) is associated with malabsorption of calcium and vitamin D, which manifests as a secondary hyperparathyroidism (SHP) and may lead to osteopenia.

METHODS

96 morbidly obese patients were studied (age 19-60 years, 23 men and 73 women, with mean initial BMI 53) following intervention by Scopinaro BPD. The change in iPTH levels, urine DPD, Pyrilinks-D of DPC and serum CTx were studied at 0, 3, 6, 12, 18 and 24 months after surgery. Postoperatively, they were given supplements of calcium and vitamin D3. The control group consisted of 67 non-obese women and 10 men.

RESULTS

The iPTH levels gradually increased after BPD, with a substantial difference compared to presurgery levels at month 6. In spite of the calcium and vitamin D supplements, 77% of the patients with presurgery SHP did maintain high levels of iPTH after 2 years. The percentage of SHP among the patients with normal pre-surgery iPTH was 58%. The basal figures of DPD/cre were significantly higher than in the control group, 9.06 (4.6-13.5) nM/mMcre vs 3.9 (2.8-5.6) in men and 6.75 (5.4-7.9) vs 7.67 (3.3-11.6) in women, but not CTx, 0.24 (0.02-0.89) vs 0.22 (0.07-0.55). After the operation, there was a noticeable increase which persisted at 2 years. There was a lack of correlation between the levels of iPTH and the bone resorption markers, i.e. the first ones decreased from month 6 in men and from month 12 in women, while the levels of iPTH continued to increase.

CONCLUSION

In obese patients, we found no correlation between iPTH levels and BMI. Supplements of calcium and vitamin D did not prevent the appearance of SHP following BPD. The patients with high pre-surgery iPTH levels have a higher risk of malabsorption of calcium and vitamin D. Following malabsorptive bariatric surgery, there is an increase in bone resorption, which results in DPD and CTx increase. Those markers do not correlate with iPTH, and this may suggest that there is a phenomenon of bone reshaping parallel to the loss of weight.

Depressive symptoms and changes in body weight exert independent and site-specific effects on bone in postmenopausal women exercising for 1 year

BACKGROUND

Lower bone mineral density (BMD) has been documented in clinically depressed populations, and depression is the second most common chronic medical condition in general medical practice. Therefore, the purpose of this study was to determine whether depressive symptoms, vitality, and body weight changes were related to 1-year BMD changes after accounting for covariates.

METHODS

Healthy postmenopausal women (n=320; 40-65 years) were recruited, and 266 women completed the study. Participants were 3-10 years postmenopausal, sedentary, and either taking hormone replacement therapy (1-3.9 years) or not taking it (at least 1 year). Exclusion criteria were: current smoking status, history of fractures, low BMD, body mass index>32.9 or <19.0, or use of bone altering medications. Regional BMD was measured from dual-energy x-ray absorptiometry at baseline and 1 year. Self-reported depressive symptoms and vitality were measured using standard questionnaires.

RESULTS

Both the vitality and depressive symptoms scores were related to BMD changes at the femur neck but not at the greater trochanter or spine. Weight change was a predictor of BMD changes in the trochanter and spine but not in the femoral neck. Weight change and vitality and/or depressive symptoms had differential and site-specific effects on BMD changes at the hip. Vitality and depressive symptoms related to femoral neck changes and weight change related to greater trochanter changes.

CONCLUSIONS

The negative impact of depressive symptoms on BMD in this population of postmenopausal women was independent of body weight or other behavioral factors such as calcium compliance or exercise.

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

OBJECTIVE

Data about the consequences of laparoscopic adjustable gastric banding (LAGB) on phospho-calcic and bone metabolism remain scarce.

SUBJECTS

We studied a group of 37 obese premenopausal women (age: 24-52 y; mean BMI = 43.7 kg/m2) who underwent LAGB.

METHODS

Serum calcium, phosphate, alkaline phosphatase, parathormone (PTH), vitamin D3, serum C-telopeptides, IGFBP-3 and IGF-1 were measured at baseline, 6, 12, 18 and 24 months after surgery. Body composition, bone mineral content (BMC) and density (BMD) were measured using dual-X-ray absorptiometry (DXA) at baseline, 6, 12 and 24 months after surgery.

RESULTS

There was no clinically significant decrease of calcemia; PTH remained stable. Serum telopeptides increased by 100% (P < 0.001) and serum IGFBP-3 decreased by 16% (P < 0.001) during the first 6 months, and then stabilized, whereas IGF-1 remained stable over the 2 y. BMC and BMD decreased, especially at the femoral neck; this decrease was significantly correlated with the decrease of waist and hip circumference.

CONCLUSIONS

We concluded that there was no evidence of secondary hyperparathyroidism 24 months after LAGB. The observed bone resorption could be linked to the decrease of IGFBP-3, although this decrease could be attributable to other confounding factors. Serum telopeptides seem to be a reliable marker of bone metabolism after gastric banding. DXA must be interpreted cautiously during major weight loss, because of the artefacts caused by the important variation of fat tissue after LAGB.

Osteoporotic Hip Fracture as a Delayed Complication of Bariatric Surgery

We describe a case in which a woman with a history of gastric bypass surgery and malabsorption syndrome sustained an intertrochanteric fracture after a fall from standing. The patient underwent surgical fixation two weeks after the injury. The radiologic appearance and pathophysiology of this event are discussed.

Metabolic complications of bariatric surgery: diagnosis and management issues

Acute complications after bariatric surgery include rhabdomyolysis and immobilization hypercalcemia. The most common long-term metabolic complications following bariatric surgery are anemia and metabolic bone disease. Neuropathy, acute Wemicke's encephalopathy and vitamin A deficiency also occur. Prevention, diagnosis,and treatment of these disorders are necessary parts of lifelong care after bariatric surgery.

Primary care perspective on bariatric surgery

The role of primary care physicians in identifying potential candidates for bariatric surgery and providing them with long-term postoperative care is gaining rapidly in importance. With the increased use of surgical procedures as treatment options for obesity, a knowledge of bariatric surgery is essential for providing optimal care. During the past decade, the number of bariatric procedures has increased, and refinements of these procedures have made them safer and more effective. Primary care physicians should know how to Identify appropriate surgical candidates and be familiar with available procedures, aware of potential complications and benefits, and able to provide lifelong monitoring and follow-up care. Thus, the primary care physician must be informed about surgical criteria, types of procedures, outcomes, complications, and the long-term monitoring needs of these patients.

Nutrient deficiencies secondary to bariatric surgery

PURPOSE OF REVIEW

The number of adolescent and adult patients submitting to bariatric surgery is increasing rapidly around the world. This review describes the literature published in the last few years concerning nutritional deficiencies after bariatric surgery as well as their etiology, incidence, treatment and prevention.

RECENT FINDINGS

Although bariatric surgery was first introduced in the 1950s, safe and successful surgical management has progressed over the last two decades and longer post-surgical follow-up data are now available. Most of the patients undergoing malabsorptive procedures will develop some nutritional deficiency, justifying mineral and multivitamin supplementation to all postoperatively. Nutrient deficiency is proportional to the length of absorptive area and to the percentage of weight loss. Low levels of iron, vitamin B12, vitamin D and calcium are predominant after Roux-en-Y gastric bypass. Protein and fat-soluble vitamin deficiencies are mainly detected after biliopancreatic diversion. Thiamine deficiency is common in patients with frequent vomiting. As the incidence of these deficiencies progresses with time, the patients should be monitored frequently and regularly to prevent malnutrition.

SUMMARY

Nutritional deficiencies can be prevented if a multidisciplinary team regularly assists the patient. Malnutrition is generally reverted with nutrient supplementation, once it is promptly diagnosed. Especial attention should be given to adolescents, mainly girls at reproductive age who have a substantial risk of developing iron deficiency. Future studies are necessary to detect nutrient abnormalities after new procedures and to evaluate the safety of bariatric surgery in younger obese patients.

Gastric bypass surgery for morbid obesity leads to an increase in bone turnover and a decrease in bone mass

Little is known about the effects on the skeleton of laparoscopic Roux-en-Y gastric bypass (LRGB) surgery for morbid obesity and subsequent weight loss. We compared 25 patients who had undergone LRGB 11 +/- 3 months previously with 30 obese controls matched for age, gender, and menopausal status. Compared with obese controls, patients post LRGB had significantly lower weight (92 +/- 16 vs. 133 +/- 20 kg; P < 0.001) and body mass index (31 +/- 5 vs. 48 +/- 7 kg/m(2); P < 0.001). Markers of bone turnover were significantly elevated in patients post LRGB compared with controls (urinary N-telopeptide cross-linked collagen type 1, 93 +/- 38 vs. 24 +/- 11 nmol bone collagen equivalents per mmol creatinine; and osteocalcin, 11.6 +/- 3.4 vs. 7.6 +/- 3.6 ng/ml; both P < 0.001). Fifteen patients were studied prospectively for an average of 9 months after LRGB. They lost 37 +/- 9 kg and had a 29 +/- 8% fall in body mass index (both P < 0.001). Urinary N-telopeptide cross-linked collagen type 1 increased by 174 +/- 168% at 3 months (P < 0.01) and 319 +/- 187% at 9 months (P < 0.01). Bone mineral density decreased significantly at the total hip (7.8 +/- 4.8%; P < 0.001), trochanter (9.3 +/- 5.7%; P < 0.001), and total body (1.6 +/- 2.0%; P < 0.05), with significant decreases in bone mineral content at these sites. In summary, within 3 to 9 months after LRGB, morbidly obese patients have an increase in bone resorption associated with a decrease in bone mass. Additional studies are needed to examine these findings over the longer term.

Bone metabolism and risk of secondary hyperparathyroidism 12 months after gastric banding in obese pre-menopausal women

OBJECTIVE

To evaluate, during the first postoperative year in obese pre-menopausal women, the effects of laparoscopic gastric banding on calcium and vitamin D metabolism, the potential modifications of bone mineral content and bone mineral density, and the risk of development of secondary hyperparathyroidism.

SUBJECTS

Thirty-one obese pre-menopausal women aged between 25 and 52 y with a mean body mass index (BMI) of 43.6 kg/m(2), scheduled for gastric banding were included. Patients with renal, hepatic, metabolic and bone disease were excluded.

METHODS

Body composition and bone mineral density (BMD) were measured at baseline, 6 and 12 months after gastric banding using dual-energy X-ray absorptiometry. Serum calcium, phosphate, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, bilirubin, urea, creatinine, uric acid, proteins, parathormone, vitamin D(3), IGF-1, IGF-BP3 and telopeptide, as well as urinary telopeptide, were measured at baseline and 1, 3, 6, 9 and 12 months after surgery.

RESULTS

After 1 y vitamin D3 remained stable and PTH decreased by 12%, but the difference was not significant. Serum telopeptide C increased significantly by 100% (P<0.001). There was an initial drop of the IGF-BP3 during the first 6 months (P<0.05), but the reduction was no longer significant after 1 y. The BMD of cortical bone (femoral neck) decreased significantly and showed a trend of a positive correlation with the increase of telopeptides (P<0.06). The BMD of trabecular bone, at the lumbar spine, increased proportionally to the reduction of hip circumference and of body fat.

CONCLUSION

There is no evidence of secondary hyperparathyroidism 1 y after gastric banding. Nevertheless biochemical bone markers show a negative remodelling balance, characterized by an increase of bone resorption. The serum telopeptide seems to be a reliable parameter, not affected by weight loss, to follow up bone turnover after gastroplasty.

Does bone change after biliopancreatic diversion?

This prospective study evaluated bone changes after biliopancreatic diversion (BPD) consisting of a distal gastrectomy, a 250 cm alimentary channel, and a 50 cm common channel. Thirty-three consecutive patients had clinical, biochemical, and bone mineral density analysis before surgery and 4 and 10 years after surgery. Iliac crest bone biopsies and special tests including parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25-OH(2)-D), bone-specific alkaline phosphatase (BAP), and osteocalcin were obtained at surgery and 4 years postoperatively. Over the years, with close metabolic surveillance, additional calcium and vitamin D were given as indicated. After BPD, serum levels of calcium and vitamin D were decreased and serum levels of PTH, BAP, and osteocalcin were increased. Bone turnover and mineralization were both increased. Mean osteoid volume (P < 0.0007) and bone formation rate in relation to bone volume (P < 0.02) were increased. Static measures of bone were altered as follows: cortical thickness decreased (P < 0.01) and trabecular bone volume increased (P < 0.01). Ten years after surgery, overall bone mineral density was unchanged at the hip and was decreased by 4% at the lumbar spine. Overall fracture risk, based on the Z score, was unchanged. Preoperative factors predicting bone loss included menopause, smoking, and preexisting osteopenia. An elevated level of 1,25-OH(2)-D was also found to be a predictor of future bone loss (r = 0.40; P < 0.002). After surgery, a greater increase in bone markers and bone turnover was associated with an increased risk of bone loss. Although elevated osteocalcin levels were associated with overall bone loss (r = 0.52; P < 0.002), lower albumin levels were associated only with bone loss at hip level (r = 0.44; P < 0.02), whereas lower calcium levels were associated only with the loss at the lumbar spine (r = 0.39; P < 0.02). Ten years after surgery, bone loss at the hip continued to depend on albumin levels (r = 0.37; P < 0.03). We concluded that bone was relatively tolerant to the metabolic changes due to BPD. Provided that there is close surveillance for metabolic disturbances, the use of appropriate supplements, and the avoidance of malnutrition, the beneficial effects of surgery far outweigh the risk of postoperative bone disease.

Obesity surgery: a model of programmed undernutrition

Surgical treatment of obesity (bariatric surgery) is the only effective long term solution for many patients. The procedures are designed to produce reduced intake, various degrees of malabsorption of nutrients, or both. Micronutrient deficiencies, especially those involved in erythropoiesis and bone metabolism, are common to nearly all bariatric surgery. They are inconsistently responsive to supplementation. The pattern of deficiency associated with gastrointestinal bypass procedures suggests that absorption of micronutrients is more dependent upon the functioning of the gut as a whole than the capacity of any single segment.