Secondary hyperparathyroidism following biliopancreatic diversion

Trends in Serum Vitamin D Levels within 12 Months after One Anastomosis Gastric Bypass (OAGB)

PURPOSE

To assess serum vitamin D trend from baseline to 12 months after one anastomosis gastric bypass (OAGB).

MATERIALS AND METHODS

In this observational cohort analysis of longitudinal data, we assessed the trend of serum vitamin D, and its associations with anthropometric, and biochemical measurements in 98 patients undergoing OAGB in a bariatric surgery center. All participants were on >800 IU/day vitamin D supplementation.

RESULTS

Vitamin D, lipid profile, creatinine, and albumin levels significantly improved at 12 months post-surgery. Vitamin D concentrations significantly increased from 26.52 ± 12.32 to 54.52 ± 27.90 ng/mL at 12 months. The correlations between vitamin D concentrations and weight, body mass index, lipid profile, ferritin, glycemic indices, and albumin were not significant. In addition, the correlations between vitamin D and parathormone, vitamin D receptor, calcium, phosphorus, body composition, and basal metabolic rate (BMR) did not reach the threshold of statistical significance at 12 months following bariatric surgery. Although there was a significant correlation between body weight and body composition (P < 0.001) and basal metabolic rate (BMR) (r = 0.762, P < 0.001) at 12 months, there were no significant correlations between weight change percent and body composition (P > 0.05), BMR (r = -0.101, P = 0.350), and vitamin D (r = 0.120, P = 0.271) at 12 months.

CONCLUSION

Our results showed that supplementation of vitamin D with dosage of >800 IU/day is sufficient for prevention of vitamin D deficiency within 12 months after OAGB surgery. Note: This data is mandatory.

Use of Home Enteral Nutrition in Malnourished Post-Bariatric Surgery Patients

BACKGROUND

Bariatric surgery is by far the most effective treatment option available for successfully achieving and maintaining weight loss in the obese population, but it can also be associated with complications that lead to malnutrition. There is limited data on how enteral nutrition (EN) can be used to provide nutrition support in such cases.

METHODS

Retrospective review of our Home Enteral Nutrition (HEN) database was conducted from February 2013 to April 2018 to identify patients who received HEN because of bariatric surgery-related complication.

RESULTS

During the study period, 72 patients (86% female, mean age 50.3 ± 11.6 years) initiated HEN because of bariatric surgical complication. Most common bariatric surgery was Roux-en-Y (74%) and most common indication for HEN was malnutrition/failure to thrive (33%). HEN was most commonly provided through nasojejunal feeds and resulted in an average increase in body weight and body mass index from 74.8 kg and 26.5, respectively, before HEN to 76.9 kg and 27.2, respectively, at the end of the HEN period. Through HEN, patients received 22.2 ± 7.9 kcal/kg/d and 1.0 ± 0.3 g/kg/d protein, meeting 94% ± 17% of their energy goals and 95% ± 29% of their protein goals. Vitamin deficiencies were noted in 69% of patients at the time of HEN initiation, which improved to 10% after enteral feeds and appropriate vitamin supplementation.

CONCLUSION

HEN is safe and effective in treating malnutrition and vitamin deficiencies that might occur as a complication of bariatric surgery, leading to avoidance of parenteral nutrition support in most cases.

Biliopancreatic Diversion in the Surgical Treatment of Morbid Obesity: Long-Term Results and Metabolic Consequences

PURPOSE

In the multidisciplinary therapeutic approach to obesity, bariatric surgery is considered the most effective treatment in weight reduction and the decrease in associated comorbidities. The objective of this work is to describe the long-term clinical and metabolic results in obese patients undergoing biliopancreatic diversion (BPD) according to Scopinaro's technique.

MATERIALS AND METHODS

Patients undergoing surgery were followed by the same multidisciplinary team in a study period of 15 years (1999-2015). A retrospective study based on a prospective database was designed, where data on the evolution of obesity-related diseases and nutritional parameters were studied.

RESULTS

Two hundred seventy-seven patients were collected; 75.5% were women. The preoperative body mass index (BMI) decreased from 52.5 kg/m² to 34.9 kg/m² 10 years after surgery. A resolution or improvement of diabetes has been observed in 85.38% of the patients; a decrease in arterial hypertension and obstructive sleep apnea syndrome were in 65.61% and 89.14%, respectively. Throughout the monitoring of the sample, protein malnutrition increased, from 1.8% after the first year of surgery to 4.5% 10 years after the operation.

CONCLUSION

Even if Scopinaro's technique is beginning to be replaced by other malabsorptive techniques, it can still be considered as an effective surgical procedure in terms of weight loss, quality of life, and evolution of obesity-related diseases. In order to avoid nutritional deficiencies, the operated patients need a strict follow-up and a supplementation adjusted to the technique.

Beneficial changes on plasma apolipoproteins A and B, high density lipoproteins and oxidized low density lipoproteins in obese women after bariatric surgery: comparison between gastric bypass and sleeve gastrectomy

Background

The beneficial effects in lipid profiles after obesity surgery might be associated with the decrease in cardiovascular risk. However, direct comparison between different surgical techniques has not been extensively performed.

Methods

In the present study we compare 20 obese women submitted to laparoscopic Roux en Y gastric bypass (RYGB) with 20 women submitted to sleeve gastrectomy (SG). Twenty control women matched for age and baseline cardiovascular risk were also included. Both patients and controls were followed up for 1 year after surgery or conventional treatment with diet and exercise, respectively. Lipid profiles were measured at baseline, 6 and 12 months later. Carotid intima-media thickness was measured by ultrasonography at baseline and at the end of the study.

Results

Women submitted to bariatric surgery showed a decrease in total cholesterol, triglycerides, oxidized-LDL and ApoB, and an increase in HDL and ApoA concentrations that occurred regardless of the surgical procedure. LDL concentrations, however, decreased only after RYGB whereas Lp(a) showed no changes. We did not observe any correlation between the changes in serum lipid concentrations and those in carotid intima-media thickness.

Conclusions

Sleeve gastrectomy and gastric bypass induce a similar beneficial effect on serum lipids in women with high cardiovascular risk 1 year after surgery.

Hypocalcemia After Bariatric Surgery: Prevalence and Associated Risk Factors

BACKGROUND

The reported prevalence of hypocalcemia after bariatric surgery ranges from 1% after Roux-en-Y gastric bypass (RYGB) to 25% after bilio-pancreatic diversion-duodenal switch (BPD-DS).

OBJECTIVE

We aimed to define the prevalence of post-operative hypocalcemia and identify clinical predisposing factors.

SETTING

The study was conducted in an Academic Medical Center, USA.

METHODS

Retrospective analysis of all patients undergoing bariatric surgery from May 2008 to December 2014 at Mayo Clinic Rochester, Minnesota was performed. Patients with revision surgeries were excluded. Hypocalcemia was defined as the lowest recorded serum calcium occurring at least 2 weeks post-operatively.

RESULTS

Nine hundred ninety-nine patients fulfilled the criteria above. After correction for serum albumin concentration, 36 patients had serum calcium ≤8.9 mg/dl. Mean serum calcium was 8.1 ± 0.6 mg/dl. The prevalence was 1.9% in the RYGB group, 9.3% in the sleeve gastrectomy (SG) group, and 10% in the BPD-DS group. In all three surgical types, patients with hypocalcemia had significantly lower serum albumin and serum 25 (OH) vitamin D concentrations when compared to their normocalcemic counterparts (P < 0.01). The presence of renal insufficiency and vitamin D deficiency was associated with the highest risk of developing hypocalcemia after surgery [OR 16.8 (6.45-47.7) and 7.1(2.9-17.3), respectively]. Pre-operative renal insufficiency increased the odds of developing hypocalcemia by 20-fold.

CONCLUSIONS

In our series, hypocalcemia was identified in 3.6% of patients undergoing all bariatric surgery. Patients who are predisposed to developing post-operative hypocalcemia, such as those with pre-operative renal impairment, or post-operative vitamin D deficiency and renal insufficiency, may benefit from increased surveillance and prevention strategies.

Vitamin D Metabolism in Bariatric Surgery

Hypovitaminosis D is common in obese patients and persists after roux-en-Y gastric bypass and sleeve gastrectomy. Several societies recommend screening for vitamin D deficiency before bariatric surgery, and replacement doses of 3000 IU/d and up to 50,000 IU 1 to 3 times per week, in case of deficiency, with periodic monitoring. These regimens are mostly based on expert opinion. Large trials are needed to assess the vitamin D dose response, by type of bariatric surgery, and evaluate the effect on surrogate markers of skeletal outcomes. Such data are essential to derive desirable vitamin D levels in this population.

Improvement in cardiovascular risk in women after bariatric surgery as measured by carotid intima-media thickness: comparison of sleeve gastrectomy versus gastric bypass

BACKGROUND

Bariatric surgery may diminish cardiovascular risk (CVR) and its associated mortality. However, studies that compare these effects with different techniques are scarce.

OBJECTIVE

To evaluate the changes in CVR as estimated by carotid intima-media thickness (IMT) after obesity surgery in women with high CVR as defined by the presence of metabolic syndrome.

SETTING

Academic hospital.

METHODS

We studied 40 severely obese women, of whom 20 received laparoscopic Roux en Y gastric bypass (RYGB) and 20 received sleeve gastrectomy (SG). Twenty control women matched for age and cardiovascular risk were also included. Patients and controls were evaluated at baseline and 1 year after surgery or conventional treatment with diet and exercise, respectively. Only 18 of the 20 women in the control group were available for analysis after 1 year. None of the women who had bariatric surgery was lost to follow-up.

RESULTS

Mean carotid IMT decreased 1 year after surgery irrespective of the surgical technique used, whereas no changes were observed in the control women who had conventional therapy (Wilks´ λ = .802, P = .002 for the interaction, P = .011 for RYGB versus controls, P = .002 for SG versus controls, P = .349 for RYGB versus SG).

CONCLUSION

Both RYGB and SG decrease CVR as measured by carotid IMT in obese women.

Biliopancreatic Diversion for Severe Obesity: Long-Term Effectiveness and Nutritional Complications

BACKGROUND

Bariatric surgery is currently the treatment of choice for those patients with severe obesity, but the procedure of choice is not clearly established. We describe weight loss and nutritional parameters in severely obese patients after biliopancreatic diversion for 10 years of follow-up.

METHODS

Patients were followed by the same multidisciplinary team, and data are shown for 10 years. Bariatric Analysis and Reporting Outcome System (BAROS) questionnaire, data regarding the evolution of obesity-related diseases, and nutritional parameters are reported.

RESULTS

Two hundred ninety-nine patients underwent biliopancreatic diversion, 76.1 % women, initial BMI 50.1 kg/m(2) (7.2). Weight loss was maintained throughout 10 years with EWL% around 65 % and EBMIL% around 70 %. More than 80 % of the patients showed EWL higher than 50 %. Blood pressure, glucose metabolism, and lipid profile clearly improved after surgery. Mean nutritional parameters remained within the normal range during follow-up. Protein malnutrition affected less than 4 % and anemia up to 16 %. Fat-soluble vitamin levels decreased along the time, with vitamin D deficiency in 61.5 % of patients. No significant differences were found either in nutritional parameters or weight loss regarding gastrectomy or gastric preservation, or common limb length longer or shorter than 55 cm

CONCLUSIONS

Biliopancreatic diversion is an effective surgical procedure in terms of weight loss, quality of life, and evolution of obesity-related diseases. Nutritional deficiencies are less frequent than feared for a malabsorptive procedure, but must be taken into account, especially for fat-soluble vitamins.

Effect of three different bariatric obesity surgery procedures on nutrient and energy digestibility using a swine experimental model

Morbid obesity is a worldwide health concern that compromises life quality and health status of obese human subjects. Bariatric surgery for treating morbid obesity remains as one of the best alternatives to promote excess weight loss and to reduce co-morbidities. We have not found studies reporting nutrients and energy balance considering digestibility trials in humans following surgery. The purpose of this study was to determine protein, lipid, fiber, energy, calcium, and phosphorous digestibility in a swine model that underwent ileal transposition (IT), sleeve gastrectomy with ileal transposition (SGIT), Roux-en-Y gastric bypass (RYGBP), and with sham operated animals (SHAM). Thirty-two pigs were randomly assigned to four laparoscopic procedures: IT (n = 8), RYGBP (n = 8), SGIT (n = 8), and Sham-operated pigs (n = 8). From day 0 postsurgery to 130, pigs were weighed monthly to determine live weight and weight gain was calculated for each month postsurgery until day 130. Food intake in a metabolic weight basis was calculated by measuring ad libitum food intake at day 130. Swine were fitted into metabolic crates to determine digestibility coefficients of dry matter, protein, fat, fiber, ash, energy, calcium, and phosphorous from day 130. A one-way ANOVA and Student-Newman-Keuls were used to detect differences in weight, food intake, and digestibility coefficients. Digestibility values for dry matter, fiber, phosphorus, and energy showed no differences among groups (P > 0.05). However, significant differences (P ≤ 0.05) were encountered among groups for fat, protein, ash, and calcium digestibilities. The RYGBP procedure, when applied to the pig model, significantly reduced calcium, fat, and ash digestibility, which did not occur with SGIT or IT procedure, when compared with Sham-operated animals.

Neuropsychiatric features associated with nutritional and metabolic status in a gastric bypass patient

Bariatric patients may present for psychiatric evaluation due to exacerbation of preexisting psychiatric disorders, new onset psychiatric disorders and/or neuropsychiatric complications associated with abnormal nutritional and metabolic states following the surgical procedure. These neuropsychiatric complications can be insidious, and clinical manifestations may vary, possibly due to the individual central nervous system (CNS) vulnerability to nutritional decline. Lack of awareness of these complications and their symptoms can result in delays in diagnosis and treatment. Identifying and correcting underlying pathophysiologic processes that lead to such neuropsychiatric syndromes can be challenging. We report a case of a patient who developed a protracted course of mood and cognitive disorder after gastric bypass surgery, which illustrates some of the complexities encountered in diagnosing and managing these patients.

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.

Vitamin D status and supplementation in morbid obesity before and after bariatric surgery

Interest in vitamin D has increased recently because of its role on multiple biologic mechanisms and the high prevalence of deficits, particularly in obese individuals. The epidemic of morbid obesity has led to a growing number of bariatric surgical procedures, the only therapeutic modality with a reasonable chance of success on a long-term basis. Vitamin D status following bariatric surgery depends on several interacting factors and should be monitored carefully. We review vitamin D, calcium and parathyroid hormone dynamics following the main types of bariatric surgery and the guidelines for the postoperative periodic assessment and therapy.

Chronic increase of bone turnover markers after biliopancreatic diversion is related to secondary hyperparathyroidism and weight loss. Relation with bone mineral density

BACKGROUND

Biliopancreatic diversion (BPD) is the most effective bariatric procedure. Around 70% of these patients have secondary hyperparathyroidism (SH) in the long term as a consequence of calcium and vitamin D malabsorption. This work was aimed to study the influence of SH on bone turnover and its relationship with bone mineral density (BMD).

METHODS

Bone turnover markers were determined in 63 BPD patients and 34 morbidly obese controls. In the BPD group, we also studied the influence of age, loss of weight, common channel length, PTH, vitamin D, and serum calcium on bone turnover as well as its relation with BMD.

RESULTS

BPD patients showed significantly higher PTH, osteocalcin, and beta-CTx levels than controls. In the multivariate regression analysis, only PTH (beta=0.42; P=0.0002), menopausal status (beta=0.31; P=0.007) and the percentage of lost BMI (beta=-0.24; P=0.03) significantly predicted the osteocalcin level (R2=0.33; F=9.56; P<0.0001). Similarly, only PTH (beta=0.39; P=0.0005), menopausal status (beta=0.37; P=0.001) and the percentage of lost BMI (beta=-0.23; P=0.04) significantly predicted the beta-CTx level (R2=0.33; F=9.82; P<0.0001). Osteocalcin and beta-CTx levels correlated negatively with BMD at lumbar spine (r=-0.38, P=0.002 and r=-0.30, P=0.02, respectively).

CONCLUSIONS

Chronic SH and the loss of weight determine a high rate of bone turnover that is associated with decreasing BMD in BPD patients.

Laparoscopic biliopancreatic diversion/duodenal switch or laparoscopic Roux-en-Y gastric bypass for super-obesity-weight loss versus side effects

BACKGROUND

Laparoscopic biliopancreatic diversion/duodenal switch (LDS) and laparoscopic Roux-en-Y gastric bypass (LRYGB) are the main surgical options for super-obese patients (body mass index >50 kg/m(2)).

METHODS

We performed a medium long-term evaluation of 13 super-obese patients who had undergone LDS compared with a control group of 19 patients who had undergone LRYGB. The patients were assessed 31 months (range 17-38) and 34 months (range 26-62) after LDS and LRYGB, respectively, for body mass index changes, relief of co-morbidities, nutrition, quality of life, postoperative bowel function, and accumulated healthcare consumption.

RESULTS

The mean body mass index decreased from 54.9 to 30.0 kg/m(2) in the LDS group and 57.8 to 39.8 kg/m(2) in the LRYGB group (P = .005). The hemoglobin A1c level was lower in the LDS group than in the LRYGB group (3.8 +/- .31% versus 4.3 +/- .43%, respectively; P = .01). The LDS patients reported greater energy intake than the LRYGB patients (3132 +/- 1392 kcal versus 2014 +/- 656 kcal, respectively; P = .021). The number of stools daily was 4.1 +/- 3.3 in the LDS group and 1.9 +/- 1.1 in the LRYGB group, P = .0482). Of the 12 patients in the LDS group, 6 reported fecal incontinence or soiling compared with 2 of 16 in the LRYGB group (P = .034). The number of outpatient visits was 5.6 +/- 4.6 for the LDS group and 2.0 +/- 1.9 for the LRYGB group (P = .016), and the number of telephone consultations was 5.0 +/- 5.6 and 1.4 +/- 1.6 for the LDS and LRYGB groups, respectively (P = .043).

CONCLUSION

LDS resulted in greater weight loss than LRYGB in super-obese patients. However, the LDS patients in our series had more frequent gastrointestinal side effects, required greater doses of calcium and vitamin supplementation, and required more postoperative monitoring. Patient satisfaction was high in both groups.

Clinical application of laparoscopic bariatric surgery: an evidence-based review

BACKGROUND

Approximately one-third of U.S. adults are obese. Current evidence suggests that surgical therapies offer the morbidly obese the best hope for substantial and sustainable weight loss, with a resultant reduction in morbidity and mortality. Minimally invasive methods have altered the demand for bariatric procedures. However, no evidence-based clinical reviews yet exist to guide patients and surgeons in selecting the bariatric operation most applicable to a given situation.

METHODS

This evidenced-based review is presented in conjunction with a clinical practice guideline developed by the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). References were reviewed by the authors and graded as to the level of evidence. Recommendations were developed and qualified by the level of supporting evidence available at the time of the associated SAGES guideline publication. The guideline also was reviewed and co-endorsed by the American Society for Metabolic and Bariatric Surgery.

RESULTS

Bariatric surgery is the most effective treatment for severe obesity, producing durable weight loss, improvement of comorbid conditions, and longer life. Patient selection algorithms should favor individual risk-benefit considerations over traditional anthropometric and demographic limits. Bariatric care should be delivered within credentialed multidisciplinary systems. Roux-en-Y gastric bypass (RGB), adjustable gastric banding (AGB), and biliopancreatic diversion with duodenal switch (BPD + DS) are validated procedures that may be performed laparoscopically. Laparoscopic sleeve gastrectomy (LSG) also is a promising procedure. Comparative data find that procedures with more dramatic clinical benefits carry greater risks, and those offering greater safety and flexibility are associated with less reliable efficacy.

CONCLUSIONS

Laparoscopic RGB, AGB, BPD + DS, and primary LSG have been proved effective. Currently, the choice of operation should be driven by patient and surgeon preferences, as well as by considerations regarding the relative importance placed on discrete outcomes.

A brown tumor after biliopancreatic diversion for severe obesity

A case of a brown tumor due to iatrogenic malabsorption following biliopancreatic diversion (BPD) is presented. A 52 year old women with a history of BPD 2 years before was referred to orthopedic surgery because of a painful lytic lesion of the left ankle. A bone biopsy revealed a giant cell tumor compatible with the diagnosis of a brown tumor. Subsequent metabolic evaluation showed severe 25-hydroxy vitamin D deficiency and secondary hyperparathyroidism (PTH 60 ng/L or twice the upper normal limit). Bone mineral density was decreased at the femoral neck (0.50 g/cm(2) ; T score of -3.92 or 66% of the expected value) and lumbar spine (T score of -1.75 or 93% of the expected value). A brown tumor can be the presenting symptom of iatrogenic malabsorption due to BPD. This case illustrates the severity of potential bone complications after BPD and the necessity of lifelong surveillance and vitamin supplements after BPD.

Role of calcium malabsorption in the development of secondary hyperparathyroidism after biliopancreatic diversion

Secondary hyperparathyroidism (SH) is a frequent metabolic complication of bariatric surgery. Around 70%of patients who undergo biliopancreatic diversion (BPD) have this complication in the long term. The aim of this study was to evaluate the relative influence of vitamin D deficiency and calcium malabsorption in the development of SH in patients who underwent BPD. We reviewed the mean values of PTH throughout the post-operative follow-up and of related biochemical data (25-hydroxyvitamin D, calcium, magnesium) of 121 patients who underwent BPD at our institute from November 1996 to November 2004 (mean follow-up 66 months). Mean PTH correlated negatively with mean 25-hydroxyvitamin D (r=-0.27, p=0.003) and with urinary calcium(r=-0.19, p=0.047), and positively with age (r=0.22, p=0.018). However, a high mean PTH was found in 48.7% patients with mean 25-hydroxyvitamin D >or=30 ng/ml and in 80.0% patients with mean 25-hydroxyvitamin D between 20 and 30 ng/ml. The mean PTH was normal in 5 patients without calcium supplements at present, and progressively increased in parallel to the calcium dose in the rest of patients, although mean 25-hydroxyvitamin D levels were not related to the calcium dose. Our data suggest that individual differences in active and/or passive calcium absorption determine intractable SH after BPD in around half of the patients who have normal levels of 25-hydroxyvitamin D and in 80% of patients with 25-hydroxyvitamin D levels between 20 and 30 ng/ml after BPD, worsening with age.

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.

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.

Surgical treatment of obesity

Obesity is very prevalent. Most treatments fail owing to hard-wired survival mechanisms, linking stress and appetite, which have become grossly maladaptive in the industrial era. Antiobesity (bariatric) surgery is a seemingly drastic, efficacious therapy for this serious disease of energy surfeit. Technical progress during the last two decades has greatly improved its safety. The surgical principles of gastric restriction and/or gastrointestinal diversion have remained largely unchanged over 40 years, although mechanisms of action have been elucidated concomitant with advances in knowledge of the molecular biology of energy balance and appetite regulation. Results of bariatric surgery in large case-series followed for at least 10 years consistently demonstrate amelioration of components of the insulin-resistance metabolic syndrome and other comorbidities, significantly improving quality of life. Furthermore, bariatric surgery has convincingly been demonstrated to reduce mortality compared with nonoperative methods. This surgery requires substantial preoperative and postoperative evaluation, teaching, and monitoring to optimize outcomes. In the absence of effective societal changes to restore a healthy energy balance, bariatric surgery is an important tool for treating a very serious disease.

Abnormalities of vitamin D and calcium metabolism after surgical treatment of morbid obesity: a study of 136 patients

OBJECTIVE

To assess the effect of bariatric surgical treatment of morbid obesity on bone mineral metabolism.

METHODS

We analyzed pertinent vitamin D and calcium metabolic variables in 136 patients who had undergone a malabsorptive bariatric operation. Measurements of bone mineral density (BMD), serum 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D [1,25-(OH)2D], parathyroid hormone (PTH), calcium, phosphorus, and alkaline phosphatase were performed. Statistical analyses assessed correlations among various factors.

RESULTS

The mean age (+/-SD) of the study group was 48.34 +/- 10.28 years. Their mean weight loss was 114.55 +/- 45.66 lb, and the mean duration since the bariatric surgical procedure was 54.02 +/- 51.88 months. Seventeen patients (12.5%) had a T-score of -2.5 or less, and 54 patients (39.7%) had a T-score between -1.0 and -2.5. Of 119 patients in whom serum 25-OHD was measured, 40 (34%) had severe hypovitaminosis D (25-OHD <8ng/mL), and 50 patients (42%) had low hypovitaminosis D (serum 25-OHD 8 to 20 ng/mL). The magnitude of weight loss correlated negatively with serum 25-OHD, calcium, phosphorus, and calcium x phosphorus product values and positively with serum alkaline phosphatase level. Serum 25-OHD and calcium concentrations correlated positively with the BMD. PTH, serum 1,25-(OH)2D, and alkaline phosphatase concentrations correlated negatively with the BMD, a reflection of the presence of secondary hyperparathyroidism, an accelerated conversion of 25-OHD to 1,25-(OH)2D by the elevated PTH levels, and increased osteoblastic activity. The mean daily vitamin D supplementation was 6,472 +/- 9,736 IU.

CONCLUSION

Hypovitaminosis D and subsequent bone loss are common in patients who have undergone a bariatric surgical procedure for morbid obesity. These patients require rigorous vitamin D supplementation.

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.

[Nutritional deficiencies associated with bariatric surgery]

Morbidly obese patients often have nutritional deficiencies, particularly in fat-soluble vitamins, folic acid and zinc. After bariatric surgery, these deficiencies may increase and others can appear, especially because of the limitation of food intake in gastric reduction surgery and of malabsorption in by-pass procedures. The latter result in more important weight loss but also increase the risk of more severe deficiencies. The protein deficiency associated with a decrease in the fat-free mass has been described in both procedures. It can sometimes require an enteral or parenteral support. Anemia can be secondary to iron deficiency, folic acid deficiency and even to vitamin B12 deficiency. Neurological disorders such as Gayet-Wernicke encephalopathy due to thiamine deficiency, or peripheral neuropathies may also be observed. Malabsorption of fat-soluble vitamins and other nutrients, especially if diagnosed after by-pass surgery, rarely cause clinical symptoms. However, some complications have been reported such as bone demineralization due to vitamin D deficiency, hair loss secondary to zinc deficiency or hemeralopia from vitamin A deficiency. A careful nutritional follow-up should be performed during pregnancy after obesity surgery, because possible deficiencies can affect the health of both the mother and child. In conclusion, increased awareness of the risk of deficiency and the systematic dosage of micronutrients are needed in the pre- and postoperative period in obese patients undergoing bariatric surgery. The case by case correction of these deficiencies is mandatory, and their systematic prevention should be evaluated.

Short-, mid- and long-term results of Larrad biliopancreatic diversion

BACKGROUND

In an effort to reduce the complications of Scopinaro's biliopancreatic diversion (BPD), in 1989 we introduced the modification of lengthening the alimentary channel preserving most of the jejunum-ileum, by creating a short biliopancreatic limb (50 cm) and maintaining 50 cm of common limb (Larrad 50-50 BPD).

METHODS

Of 343 patients who consecutively underwent Larrad 50-50 BPD surgery, 325, 194 and 65 patients were evaluated at 2, 5 and 10 years after surgery, respectively, in terms of surgical morbidity, mortality, metabolic sequelae and weight. Mean age was 41.2 years (range 17-62), mean initial weight 151.2 kg (range 97-260), and BMI was 52.2 kg/m2. Maximum follow-up was 120 months.

RESULTS

Mortality was 0.87% and surgical morbidity 7.6%. There were no cases of suture dehiscence, peritonitis or stomal stenosis. Percent excess weight loss (%EWL) stabilized 2 years after surgery and at 10 years was 77.8 +/- 11.2% for morbidly obese patients and 63.2 +/- 11.8% for super-obese patients. The main complications were 43.8% clinical incisional hernia, 2.5% severe diarrhea, 10.8% mild diarrhea and 9.2% constipation. 30% experienced anemia and/or iron deficiency, and 3% required iron parenterally or lifelong zinc supplements. 28% showed preoperative PTH elevation and 30% vitamin D deficiency; these values postoperatively increased to 45% and 43% respectively. Both these alterations were resolved using supplements, although 12% needed increased doses of vitamin D. The incidence of severe hypoproteinemia was 0.29%. No patient required surgical reversal. When independently evaluated, failure rates in terms of insufficient weight loss were 9% at 5 years and 11.3% at 10 years for morbidly obese, and 12.2% and 14% for super-obese patients respectively. According to the BAROS questionnaire, 75% of surgery outcomes were excellent or very good, 18% good, 5% fair and 2% failures.

CONCLUSIONS

After 2, 5 and 10 years, Larrad's BPD has offered excellent results in terms of weight loss and quality of life, a low rate of metabolic sequelae, including a hypoproteinemia rate < 0.5%, and a revision surgery rate 0%.

Phosphocalcic Metabolism after Biliopancreatic Diversion

BACKGROUND

Malabsorptive techniques to treat morbid obesity have been followed by alterations in phosphocalcic metabolism. Knowledge of the preoperative situation is important to assess the influence of these techniques on phosphocalcic metabolism and to consider treatments for these alterations.

METHODS

61 consecutive morbidly obese patients (50 women, 11 men, age 19 to 63 years) having had biliopancreatic diversion (BPD) were studied in a prospective manner. Preoperative and postoperative levels of calcium, phosphorus, 25-hydroxyvitamin D, tartrate resistant acid phosphate, plasma parathormone (PTH), tubular absorption of phosphate, and urinary calcium and pyridinolines were analyzed, as well as the potential risk factors for their alterations. Follow-up of all patients was a minimum of 4 years.

RESULTS

Before BPD, 42.3% of patients presented an increase in PTH and 54% a decrease in the 25-OH vitamin D, but the values of calcium and plasma phosphorus maintained at normal level. 81.8% of the patients with an increase in the PTH maintained high levels after BPD, while 60% of those with a normal preoperative PTH also presented hyperparathyroidism 4 years after the intervention. A correlation between the levels of plasma PTH and body mass index was not found.

CONCLUSION

Morbid obesity is accompanied by a high percentage of hyperparathyroidism. BPD produces malabsorption of vitamin D during the first years, favoring the persistence or appearance of hyperparathyroidism. It is important to recognize and treat the secondary hyperparathyroidism. The postoperative period could necessitate more energetic interventions to get more efficient control of the phosphocalcic metabolism.

Hypovitaminosis D and Morbid Obesity

There is scarce and flawed data regarding vitamin D status in morbidly obese patients. More often than not, vitamin D deficits have been linked with bariatric surgery, not considering that the deficit may well precede surgery. Moreover, several pathophysiologic mechanism might explain, in part, vitamin D deficits. Conversely, the association between vitamin D deficits and secondary hyperparathyroidism in morbidly obese patients has been reported before and after bariatric surgery. Taking into account the elevated prevalence of vitamin D deficits in morbidly obese patients, its associated comorbidity, and the efficacy and low cost of its treatment to restore normal serum values of 25-OH-vitamin D, it seems advisable to recommend routine monitoring of serum calcium, phosphorus, and 25-OH-vitamin D levels in morbidly obese patients and to implement calcium and vitamin D supplementation whenever necessary.

Surgery for morbid obesity

The prevalence of morbid obesity in the UK population is rising, bringing with it increased levels of cardiovascular disease, diabetes, arthritis and early mortality. The overall cost to the health service is high, and is set to increase over the coming decades as the overweight population ages. Dietary, lifestyle and pharmacological interventions offer at best reasonable, short-term weight reduction and often fail. Surgical intervention is a safe and effective means of delivering marked long-term weight reduction. This article compares and contrasts the options available for surgical treatment of morbid obesity based on a review of the current literature.

Common channel length predicts outcomes of biliopancreatic diversion alone and with the duodenal switch surgery

BACKGROUND

The optimal common channel (CC) length for malabsorptive weight loss surgeries is unknown even though these surgeries were developed in the 1970s (biliopancreatic diversion [BPD]) and the 1990s (biliopancreatic diversion with a duodenal switch [BPD DS]). We hypothesized that the length of the CC correlates with a successful weight loss result.

METHODS

We evaluated 3 groups of patients based on the length of the CC whose duration of follow-up evaluation was at least 1 year. We reviewed all patients who had either an open BPD (5 patients) or a BPD DS (119 patients) from August 1998 to October 2003, for which D.B.M. was the participating surgeon.

RESULTS

Group I comprised 15 patients: their preoperative body mass index (BMI) was 53.9 kg/m(2); 73.3% of patients had a BMI more than 50, and the CC length was 150 cm. Group II comprised 76 patients: their preoperative BMI was 54.25 kg/m(2); 73.3% of patients had a BMI more than 50, and the CC length was 100 cm. Group III comprised 33 patients: their preoperative BMI was 60.1 kg/m(2); 84% of patients had a BMI more than 50, and the CC length was 80 to 90 cm. The mean weight loss in group I was 45 kg (44% mean excess weight loss). The mean weight loss in groups II and III was 55.8 and 61.5 kg, respectively (a 57% and 54.8% mean excess weight loss, respectively) (all P < .05 by analysis of variance). A weight loss of greater than 50% of excess body weight occurred in 40% of patients in group I versus 63% of patients in groups II and III combined (P < .01 by chi(2)).

CONCLUSIONS

The length of the CC contributes significantly to successful excess weight loss in BPD and BPD DS patients. In general, the length of the CC should not exceed 100 cm.

Follow-up of nutritional and metabolic problems after bariatric surgery

Over the next several years, the number of patients who will have had bariatric surgery for morbid obesity will reach close to a million. Several well-described nutritional problems such as B12 and iron deficiency will be noted in these patients. Many of these patients will be lost to the original surgeon and will now be in the care of the "other physicians." These and other mineral and vitamin problems will need to be screened and treated. If these problems are left undiagnosed, severe and irreparable problems can result. Early problems, such as vomiting and dumping syndrome, will be easily recognized and treated, but other long-term problems, such as changes in bone metabolism, will need to be monitored. Again, if some of these long-term problems are not addressed in a timely fashion, then eventual treatment becomes much more difficult. This commentary will cover the common as well newer problems that are now developing in the patient who has had bariatric surgery. Patients who have undergone bariatric surgery require medical follow-up for reasons that are often determined by the type of surgical procedure performed. The majority of this review will deal with patients who have had the standard Roux-en-Y gastric bypass, which is a primarily restrictive procedure with a mild component of noncaloric malabsorption. At the end of this report, a short section will be devoted to the problems associated with the malabsorptive procedures.

Bone and gastric bypass surgery: effects of dietary calcium and vitamin D

OBJECTIVE

To examine bone mass and metabolism in women who had previously undergone Roux-en-Y gastric bypass (RYGB) and determine the effect of supplementation with calcium (Ca) and vitamin D.

RESEARCH METHODS AND PROCEDURES

Bone mineral density and bone mineral content (BMC) were examined in 44 RYGB women (> or = 3 years post-surgery; 31% weight loss; BMI, 34 kg/m(2)) and compared with age- and weight-matched control (CNT) women (n = 65). In a separate analysis, RYGB women who presented with low bone mass (n = 13) were supplemented to a total 1.2 g Ca/d and 8 microg vitamin D/d over 6 months and compared with an unsupplemented CNT group (n = 13). Bone mass and turnover and serum parathyroid hormone (PTH) and 25-hydroxyvitamin D were measured.

RESULTS

Bone mass did not differ between premenopausal RYGB and CNT women (42 +/- 5 years), whereas postmenopausal RYGB women (55 +/- 7 years) had higher bone mineral density and BMC at the lumbar spine and lower BMC at the femoral neck. Before and after dietary supplementation, bone mass was similar, and serum PTH and markers of bone resorption were higher (p < 0.001) in RYGB compared with CNT women and did not change significantly after supplementation.

DISCUSSION

Postmenopausal RYGB women show evidence of secondary hyperparathyroidism, elevated bone resorption, and patterns of bone loss (reduced femoral neck and higher lumbar spine) similar to other subjects with hyperparathyroidism. Although a modest increase in Ca or vitamin D does not suppress PTH or bone resorption, it is possible that greater dietary supplementation may be beneficial.

Biliopancreatic diversion in the surgical treatment of morbid obesity

Biliopancreatic diversion is a malabsorptive technique of bariatric surgery that has gained wide acceptance in the Western world. It is performed in one of two ways: In its classic form it consists of partial gastrectomy with a Roux-en-Y gastroenterostomy; in its duodenal switch form a vertical sleeve gastrectomy is combined with a duodenoenterostomy. Both techniques realize diversion of biliopancreatic juice, thereby creating a mild form of malabsorption. Weight loss has been approximately 70% of initial excess weight, exceeding that obtained with most other bariatric procedures. Iron, calcium, and vitamin deficiencies may occur, especially with classic biliopancreatic diversion, and must be prevented with adequate supplements during vigorous follow-up. Weight loss is followed by a substantial reduction in the co-morbidities that are present in many morbidly obese patients. Biliopancreatic diversion should be included in each obesity clinic program and be proposed for morbidly obese patients who are having difficulty with the prospect of continuous restraint of food intake or problems due to failed gastric restrictive interventions. The postoperative results in such patients have been good and have substantially improved quality of life and self-esteem in this category of morbidly obese patients.

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 and its surgical management

Obesity is increasing in epidemic proportions world-wide. Even mild degrees of obesity have adverse health effects and are associated with diminished longevity. For this reason aggressive dietary intervention is recommended. Patients with body mass indices exceeding 40 have medically significant obesity in which the risk of serious health consequences is substantial, with concomitant significant reductions in life expectancy. For these patients, sustained weight loss rarely occurs with dietary intervention. For the appropriately selected patients, surgery is beneficial. Various operations have been proposed for the treatment of obesity, many of which proved to have serious complications precluding their efficacy. A National Institutes of Health Consensus Panel reviewed the indications and types of operations, concluding that the banded gastroplasty and gastric bypass were acceptable operations for treating seriously obese patients. Surgical treatment is associated with sustained weight loss for seriously obese patients who uniformly fail nonsurgical treatment. Following weight loss there is a high cure rate for diabetes and sleep apnea, with significant improvement in other complications of obesity such as hypertension and osteoarthritis.

Vitamin A deficiency in a newborn resulting from maternal hypovitaminosis A after biliopancreatic diversion for the treatment of morbid obesity

BACKGROUND

Biliopancreatic diversion (BPD) has been advocated for the treatment of morbid obesity. This procedure has the theoretical advantage that patients retain normal eating capacity and lose weight irrespective of their eating habits. However, vitamin deficiencies may develop because BPD causes malabsorption.

OBJECTIVE

This report describes a 40-y-old mother and her newborn infant, who developed vitamin A deficiency as a result of iatrogenic maternal malabsorption after BPD. Our primary objective is to show that BPD patients need close follow-up and lifelong micronutrient supplementation to prevent nutrient deficiencies in themselves and their offspring.

DESIGN

The medical records of the mother and infant were reviewed, and their clinical course was followed until 10 mo postpartum. The mother was also interviewed on several occasions about her medical care, follow-up, and supplemental vitamin use.

RESULTS

The mother developed night blindness with undetectable serum vitamin A concentrations in the third trimester of her pregnancy. Her vitamin A deficiency was untreated until she delivered her infant. At delivery, the infant also had vitamin A deficiency. He may have permanent retinal damage, but this is still unclear because the ophthalmologic examination performed at 2 mo of age was inconclusive.

CONCLUSIONS

Complications of BPD may take many years to develop, and the signs and symptoms may be subtle. Because of the malabsorption that results from BPD, patients need lifelong follow-up and appropriate vitamin supplementation to prevent deficiencies. These nutrient deficiencies can also affect the offspring of female BPD patients.

Surgery for obesity

As were most types of gastrointestinal surgery, antiobesity surgery was dominated by the development of laparoscopic techniques during the last decade. The feasibility of performing any primary antiobesity operation safely laparoscopically was convincingly demonstrated during the last 2 years. This represents a significant continued improvement in the perioperative safety of "bariatric" surgery. However, antiobesity surgery entails very much more than technique. Unfortunately, little progress has been made in optimizing patient selection, improving follow-up, and devising strategies for reoperative antiobesity surgery. The latest publications in the field are mainly confirmatory, demonstrating durable medically significant weight loss resulting in comorbidity reduction with increased life expectancy. The most interesting contribution of this surgery is provision of "experimental models" using gastrointestinal physiology to study the pathophysiology of obesity and undernutrition by guaranteeing substantial weight loss maintained long-term. It is unfortunate that surgery for obesity is seriously underutilized.

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.