Weight and Metabolic Outcomes 12 Years after Gastric Bypass.

BACKGROUND: Few long-term or controlled studies of bariatric surgery have been conducted to date. We report the 12-year follow-up results of an observational, prospective study of Roux-en-Y gastric bypass that was conducted in the United States. METHODS: A total of 1156 patients with severe obesity comprised three groups: 418 patients who sought and underwent Roux-en-Y gastric bypass (surgery group), 417 patients who sought but did not undergo surgery (primarily for insurance reasons) (nonsurgery group 1), and 321 patients who did not seek surgery (nonsurgery group 2). We performed clinical examinations at baseline and at 2 years, 6 years, and 12 years to ascertain the presence of type 2 diabetes, hypertension, and dyslipidemia. RESULTS: The follow-up rate exceeded 90% at 12 years. The adjusted mean change from baseline in body weight in the surgery group was -45.0 kg (95% confidence interval [CI], -47.2 to -42.9; mean percent change, -35.0) at 2 years, -36.3 kg (95% CI, -39.0 to -33.5; mean percent change, -28.0) at 6 years, and -35.0 kg (95% CI, -38.4 to -31.7; mean percent change, -26.9) at 12 years; the mean change at 12 years in nonsurgery group 1 was -2.9 kg (95% CI, -6.9 to 1.0; mean percent change, -2.0), and the mean change at 12 years in nonsurgery group 2 was 0 kg (95% CI, -3.5 to 3.5; mean percent change, -0.9). Among the patients in the surgery group who had type 2 diabetes at baseline, type 2 diabetes remitted in 66 of 88 patients (75%) at 2 years, in 54 of 87 patients (62%) at 6 years, and in 43 of 84 patients (51%) at 12 years. The odds ratio for the incidence of type 2 diabetes at 12 years was 0.08 (95% CI, 0.03 to 0.24) for the surgery group versus nonsurgery group 1 and 0.09 (95% CI, 0.03 to 0.29) for the surgery group versus nonsurgery group 2 (P<0.001 for both comparisons). The surgery group had higher remission rates and lower incidence rates of hypertension and dyslipidemia than did nonsurgery group 1 (P<0.05 for all comparisons). CONCLUSIONS: This study showed long-term durability of weight loss and effective remission and prevention of type 2 diabetes, hypertension, and dyslipidemia after Roux-en-Y gastric bypass. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Effect of a randomised 12-week resistance training programme on muscular strength, cross-sectional area and muscle quality in women having undergone Roux-en-Y gastric bypass.

The purpose of this study was to examine the effect of a 12-week resistance training programme on fat-free mass (FFM), muscle cross-sectional area, muscular strength and muscle quality in women who underwent Roux-en-Y gastric bypass surgery. Participants were 16 women (mean age = 44.9 ± 10.2 years) from bariatric surgical groups who were randomly assigned into either a control or an intervention group. Air displacement plethysmography measured FFM and magnetic resonance imaging measured quadriceps muscle cross-sectional area and whole thigh muscle cross-sectional area. Muscular strength and quality was assessed using an estimated 1-Repetition Maximum assessment. All measurements were collected twice, at baseline and at a 12-week follow-up. There were significantly greater improvements in leg press strength (mean differences = 55.4%, P < 0.001, Cohen's d = 2.4), leg extension strength (mean differences = 18.0%, P = 0.014, Cohen's d = 0.86) and leg press muscle quality (mean differences = 54.5%, P < 0.001, Cohen's d = 1.9) in the intervention group compared to the control group following the resistance training programme. The resistance training intervention significantly improved muscular strength and quality; however, it did not illicit changes in FFM or muscle cross-sectional area in women who underwent Roux-en-Y gastric bypass surgery.

APOH interacts with FTO to predispose to healthy thinness.

We identified eight candidate thinness predisposition variants from the Illumina HumanExome chip genotyped on members of pedigrees selected for either healthy thinness or severe obesity. For validation, we tested the candidates for association with healthy thinness in additional pedigree members while accounting for effects of obesity-associated genes: NPFFR2, NPY2R, FTO, and MC4R. Significance was obtained for the interaction of FTO rs9939609 with APOH missense variant rs52797880 (minor allele frequency 0.054). The thinness odds ratio was estimated as 2.15 (p < 0.05) for the combination of APOH heterozygote with the homozygote for the non-obesity FTO allele. Significance was not obtained for any other combination of a candidate variant with an obesity gene or for any of the eight candidates tested independently.

All-Cause and Cause-Specific Mortality Associated with Bariatric Surgery: A Review.

The question of whether or not nonsurgical intentional or voluntary weight loss results in reduced mortality has been equivocal, with long-term mortality following weight loss being reported as increased, decreased, and not changed. In part, inconsistent results have been attributed to the uncertainty of whether the intentionality of weight loss is accurately reported in large population studies and also that achieving significant and sustained voluntary weight loss in large intervention trials is extremely difficult. Bariatric surgery has generally been free of these conflicts. Patients voluntarily undergo surgery and the resulting weight is typically significant and sustained. These elements, combined with possible non-weight loss-related mechanisms, have resulted in improved comorbidities, which likely contribute to a reduction in long-term mortality. This paper reviews the association between bariatric surgery and long-term mortality. From these studies, the general consensus is that bariatric surgical patients have: 1) significantly reduced long-term all-cause mortality when compared to severely obese non-bariatric surgical control groups; 2) greater mortality when compared to the general population, with the exception of one study; 3) reduced cardiovascular-, stroke-, and cancer-caused mortality when compared to severely obese non-operated controls; and 4) increased risk for externally caused death such as suicide.

Long-term all-cause and cause-specific mortality for four bariatric surgery procedures.

OBJECTIVE: This retrospective study incorporated long-term mortality results after different bariatric surgery procedures and for multiple age at surgery groups. METHODS: Participants with bariatric surgery (surgery) and without (non-surgery) were matched (1:1) for age, sex, BMI, and surgery date with a driver license application/renewal date. Mortality rates were compared by Cox regression, stratified by sex, surgery type, and age at surgery. RESULTS: Participants included 21,837 matched surgery and non-surgery pairs. Follow-up was up to 40 years (mean [SD], 13.2 [9.5] years). All-cause mortality was 16% lower in surgery compared with non-surgery groups (hazard ratio, 0.84; 95% CI: 0.79-0.90; p < 0.001). Significantly lower mortality after bariatric surgery was observed for both females and males. Mortality after surgery versus non-surgery decreased significantly by 29%, 43%, and 72% for cardiovascular disease, cancer, and diabetes, respectively. The hazard ratio for suicide was 2.4 times higher in surgery compared with non-surgery participants (95% CI: 1.57-3.68; p < 0.001), primarily in participants with ages at surgery between 18 and 34 years. CONCLUSIONS: Reduced all-cause mortality was durable for multiple decades, for multiple bariatric surgical procedures, for females and males, and for greater than age 34 years at surgery. Rate of death from suicide was significantly higher in surgery versus non-surgery participants only in the youngest age at surgery participants.

Long-term cancer outcomes after bariatric surgery.

OBJECTIVE: Obesity is associated with increased cancer risk. Because of the substantial and sustained weight loss following bariatric surgery, postsurgical patients are ideal to study the association of weight loss and cancer. METHODS: Retrospectively (1982-2019), 21,837 bariatric surgery patients (surgery, 1982-2018) were matched 1:1 by age, sex, and BMI with a nonsurgical comparison group. Procedures included gastric bypass, gastric banding, sleeve gastrectomy, and duodenal switch. Primary outcomes included cancer incidence and mortality, stratified by obesity- and non-obesity-related cancers, sex, cancer stage, and procedure. RESULTS: Bariatric surgery patients had a 25% lower risk of developing any cancers compared with a nonsurgical comparison group (hazard ratio [HR] 0.75; 95% CI 0.69-0.81; p < 0.001). Cancer incidence was lower among female (HR 0.67; 95% CI 0.62-0.74; p < 0.001) but not male surgery patients, with the HR lower for females than for males (p < 0.001). Female surgery patients had a 41% lower risk for obesity-related cancers (i.e., breast, ovarian, uterine, and colon) compared with nonsurgical females (HR 0.59; 95% CI 0.52-0.66; p < 0.001). Cancer mortality was significantly lower after surgery in females (HR 0.53; 95% CI 0.44-0.64; p < 0.001). CONCLUSIONS: Bariatric surgery was associated with lower all-cancer and obesity-related cancer incidence among female patients. Cancer mortality was significantly lower among females in the surgical group versus the nonsurgical group.

Gastrointestinal surgery: cardiovascular risk reduction and improved long-term survival in patients with obesity and diabetes.

Whereas the initial focus of bariatric surgery primarily focused on weight loss and was considered by many clinicians and the public as a cosmetic-driven procedure, this surgical therapy is now recognized as a successful approach to reducing cardiovascular disease risk and the only substantial and sustainable weight loss treatment for most severely obese patients. In addition, as a result of the multiple metabolic-related benefits associated with bariatric surgery, efforts to understand physiologic and biochemical mechanisms have led to a dramatic increase in scientific discovery. This review focuses on bariatric research conducted during the past two decades in relation to cardiovascular disease risk and the effects of this surgical therapy on diabetes. Cardiovascular and diabetes mortality and morbidity associated with bariatric surgery are reviewed. The opportunity for bariatric (and/or metabolic) surgery to provide a preventive strategy for cardiovascular disease and diabetes as well as treatment therapy is presented for clinical consideration.

Health benefits of gastric bypass surgery after 6 years.

CONTEXT: Extreme obesity is associated with health and cardiovascular disease risks. Although gastric bypass surgery induces rapid weight loss and ameliorates many of these risks in the short term, long-term outcomes are uncertain. OBJECTIVE: To examine the association of Roux-en-Y gastric bypass (RYGB) surgery with weight loss, diabetes mellitus, and other health risks 6 years after surgery. DESIGN, SETTING, AND PARTICIPANTS: A prospective Utah-based study conducted between July 2000 and June 2011 of 1156 severely obese (body mass index [BMI] ≥ 35) participants aged 18 to 72 years (82% women; mean BMI, 45.9; 95% CI, 31.2-60.6) who sought and received RYGB surgery (n = 418), sought but did not have surgery (n = 417; control group 1), or who were randomly selected from a population-based sample not seeking weight loss surgery (n = 321; control group 2). MAIN OUTCOME MEASURES: Weight loss, diabetes, hypertension, dyslipidemia, and health-related quality of life were compared between participants having RYGB surgery and control participants using propensity score adjustment. RESULTS: Six years after surgery, patients who received RYGB surgery (with 92.6% follow-up) lost 27.7% (95% CI, 26.6%-28.9%) of their initial body weight compared with 0.2% (95% CI, -1.1% to 1.4%) gain in control group 1 and 0% (95% CI, -1.2% to 1.2%) in control group 2. Weight loss maintenance was superior in patients who received RYGB surgery, with 94% (95% CI, 92%-96%) and 76% (95% CI, 72%-81%) of patients receiving RYGB surgery maintaining at least 20% weight loss 2 and 6 years after surgery, respectively. Diabetes remission rates 6 years after surgery were 62% (95% CI, 49%-75%) in the RYGB surgery group, 8% (95% CI, 0%-16%) in control group 1, and 6% (95% CI, 0%-13%) in control group 2, with remission odds ratios (ORs) of 16.5 (95% CI, 4.7-57.6; P < .001) vs control group 1 and 21.5 (95% CI, 5.4-85.6; P < .001) vs control group 2. The incidence of diabetes throughout the course of the study was reduced after RYGB surgery (2%; 95% CI, 0%-4%; vs 17%; 95% CI, 10%-24%; OR, 0.11; 95% CI, 0.04-0.34 compared with control group 1 and 15%; 95% CI, 9%-21%; OR, 0.21; 95% CI, 0.06-0.67 compared with control group 2; both P < .001). The numbers of participants with bariatric surgery-related hospitalizations were 33 (7.9%), 13 (3.9%), and 6 (2.0%) for the RYGB surgery group and 2 control groups, respectively. CONCLUSION: Among severely obese patients, compared with nonsurgical control patients, the use of RYGB surgery was associated with higher rates of diabetes remission and lower risk of cardiovascular and other health outcomes over 6 years.

Proteome-wide associations with short- and long-term weight loss and regain after Roux-en-Y gastric bypass surgery.

OBJECTIVE: Gastric bypass surgery results in long-term weight loss. Small studies have examined protein changes during rapid weight loss (up to 1 or 2 years post surgery). This study tested whether short-term changes were maintained after 12 years. METHODS: A 12-year follow-up, protein-wide association study of 1,297 SomaLogic aptamer-based plasma proteins compared short- (2-year) and long-term (12-year) protein changes in 234 individuals who had gastric bypass surgery with 144 nonintervened individuals with severe obesity. RESULTS: There were 51 replicated 12-year protein changes that differed between the surgery and nonsurgery groups. Adjusting for change in BMI, only 12 proteins remained significant, suggesting that BMI change was the primary reason for most protein changes and not non-BMI-related surgical effects. Protein changes were related to BMI changes during both weight-loss and weight-regain periods. The significant proteins were associated primarily with lipid, uric acid, or resting energy expenditure clinical variables and metabolic pathways. Eight protein changes were associated with 12-year diabetes remission, including apolipoprotein M, sex hormone binding globulin, and adiponectin (p < 3.5 × 10-5 ). CONCLUSIONS: This study showed that most short-term postsurgical changes in proteins were maintained at 12 years. Systemic protection pathways, including inflammation, complement, lipid, and adipocyte pathways, were related to the long-term benefits of gastric bypass surgery.

Following Roux-en-Y gastric bypass surgery, serum ceramides demarcate patients that will fail to achieve normoglycemia and diabetes remission.

BACKGROUND: Obesity is a prevalent health threat and risk factor for type 2 diabetes. In this study, we evaluate the relationship between ceramides, which inhibit insulin secretion and sensitivity, and markers of glucose homeostasis and diabetes remission or recursion in patients who have undergone a Roux-en-Y gastric bypass (RYGB). METHODS: The Utah Obesity Study is a prospective cohort study, with targeted ceramide and dihydroceramide measurements performed on banked serum samples. The Utah Obesity Study consists of 1,156 participants in three groups: a RYGB surgery group, a non-surgery group denied insurance coverage, and severely obese population controls. Clinical examinations and ceramide assessments were performed at baseline and 2 and 12 years after RYGB surgery. FINDINGS: Surgery patients (84% female, 42.2 ± 10.6 years of age at baseline) displayed lower levels of several serum dihydroceramides and ceramides at 2 and 12 years after RYGB. By contrast, neither the control group (77% female, 48.7± 6.4 years of age at baseline) nor the non-surgery group (95% female, 43.0± 11.4 years of age at baseline) experienced significant decreases in any species. Using a linear mixed effect model, we found that multiple dihydroceramides and ceramides positively associated with the glycemic control measures HOMA-IR and HbA1c. In surgery group participants with prevalent diabetes, ceramides inversely predict diabetes remission, independent of changes in weight. CONCLUSIONS: Ceramide decreases may explain the insulin sensitization and diabetes resolution observed in most RYGB surgery patients. FUNDING: Funded by the National Institutes of health (NIH), The Juvenile Diabetes Research Foundation, and the American Heart Association.

Genetic evidence for a role of adiponutrin in the metabolism of apolipoprotein B-containing lipoproteins.

Adiponutrin (PNPLA3) is a predominantly liver-expressed transmembrane protein with phospholipase activity that is regulated by fasting and feeding. Recent genome-wide association studies identified PNPLA3 to be associated with hepatic fat content and liver function, thus pointing to a possible involvement in the hepatic lipoprotein metabolism. The aim of this study was to examine the association between two common variants in the adiponutrin gene and parameters of lipoprotein metabolism in 23,274 participants from eight independent West-Eurasian study populations including six population-based studies [Bruneck (n = 800), KORA S3/F3 (n = 1644), KORA S4/F4 (n = 1814), CoLaus (n = 5435), SHIP (n = 4012), Rotterdam (n = 5967)], the SAPHIR Study as a healthy working population (n = 1738) and the Utah Obesity Case-Control Study including a group of 1037 severely obese individuals (average BMI 46 kg/m2) and 827 controls from the same geographical region of Utah. We observed a strong additive association of a common non-synonymous variant within adiponutrin (rs738409) with age-, gender-, and alanine-aminotransferase-adjusted lipoprotein concentrations: each copy of the minor allele decreased levels of total cholesterol on average by 2.43 mg/dl (P = 8.87 x 10(-7)), non-HDL cholesterol levels by 2.35 mg/dl (P = 2.27 x 10(-6)) and LDL cholesterol levels by 1.48 mg/dl (P = 7.99 x 10(-4)). These associations remained significant after correction for multiple testing. We did not observe clear evidence for associations with HDL cholesterol or triglyceride concentrations. In conclusion, our study suggests that adiponutrin is involved in the metabolism of apoB-containing lipoproteins.

A common variant in the adiponutrin gene influences liver enzyme values.

BACKGROUND: Two recent genome-wide association studies identified the liver expressed transmembrane protein adiponutrin to be associated with liver related phenotypes such as non-alcoholic fatty liver disease and liver function enzymes. These associations were not uniformly reported for various ethnicities. The aim of this study was to investigate a common non-synonymous variant within adiponutrin (rs738409, exon 3) with parameters of liver function in three independent West Eurasian study populations including a total of 4290 participants. METHODS: The study was performed in (1) the population based Bruneck Study (n=783), (2) the Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk Study from Austria based on a healthy working population (n=1705), and the Utah Obesity Case-Control Study including a group of 1019 severely obese individuals (average body mass index 46.0 kg/m(2)) and 783 controls from the same geographical region of Utah. Liver enzymes measured were alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT). RESULTS: A strong recessive association of this polymorphism was found with age and gender adjusted ALT and AST concentrations: being homozygous for the minor allele resulted in a highly significant increase of ALT concentration of 3.53 U/l (p=1.86 x 10(-9)) and of AST concentration of 2.07 U/l (p=9.58 x 10(-6)), respectively. The associations were consistently found in all three study populations. CONCLUSION: The highly significant associations of this transversion polymorphism within the adiponutrin gene with increased ALT and AST concentrations support a role for adiponutrin as a susceptibility gene for hepatic dysfunction.

Associations of Visceral, Subcutaneous, Epicardial, and Liver Fat with Metabolic Disorders up to 14 Years After Weight Loss Surgery.

Background: Bariatric surgery leads to long-term remission and reduced incidence of diabetes, hypertension, and dyslipidemia. Short-term studies suggest reduction in specific fat depots may be more predictive of health improvement than reduced body mass index (BMI). Visceral, subcutaneous, epicardial, and liver fat, measured 11 years after bariatric surgery, were associated with long-term remission and incidence of diabetes, dyslipidemia, and hypertension. Methods: Fat depots an average of 11 (maximum 14) years after surgery were quantified by noncontrast computed tomography in subjects who did (N = 261; 86% gastric bypass) or did not (N = 243) have bariatric surgery. Multiple regression related fat depots to disease endpoints with and without adjustment for change in BMI and surgical status. Results: Visceral fat was 42% lower, subcutaneous fat 20% lower, epicardial fat 30% lower, and liver-to-spleen density ratio 9% higher at follow-up in the bariatric surgery group compared with the nonsurgery group (all P < 0.01). Higher visceral fat at follow-up exam was significantly associated with reduced remission and increased incidence of diabetes, hypertension, and dyslipidemia. Subcutaneous fat was not associated with disease. The liver-to-spleen ratio was associated with the remission and incidence of hypertriglyceridemia and not with other fat depots. Epicardial fat was related to incidence of elevated low-density lipoprotein cholesterol and low high-density lipoprotein cholesterol. Conclusions: Whether or not a patient shows greater long-term diabetes, dyslipidemia, or hypertension remission or incidence after bariatric surgery appears dependent on the amount of fat within specific fat depots measured at follow-up. Furthermore, associations of the three disease endpoints with different fat depots suggest varied fat depot pathology.

Long-term mortality after gastric bypass surgery.

BACKGROUND: Although gastric bypass surgery accounts for 80% of bariatric surgery in the United States, only limited long-term data are available on mortality among patients who have undergone this procedure as compared with severely obese persons from a general population. METHODS: In this retrospective cohort study, we determined the long-term mortality (from 1984 to 2002) among 9949 patients who had undergone gastric bypass surgery and 9628 severely obese persons who applied for driver's licenses. From these subjects, 7925 surgical patients and 7925 severely obese control subjects were matched for age, sex, and body-mass index. We determined the rates of death from any cause and from specific causes with the use of the National Death Index. RESULTS: During a mean follow-up of 7.1 years, adjusted long-term mortality from any cause in the surgery group decreased by 40%, as compared with that in the control group (37.6 vs. 57.1 deaths per 10,000 person-years, P<0.001); cause-specific mortality in the surgery group decreased by 56% for coronary artery disease (2.6 vs. 5.9 per 10,000 person-years, P=0.006), by 92% for diabetes (0.4 vs. 3.4 per 10,000 person-years, P=0.005), and by 60% for cancer (5.5 vs. 13.3 per 10,000 person-years, P<0.001). However, rates of death not caused by disease, such as accidents and suicide, were 58% higher in the surgery group than in the control group (11.1 vs. 6.4 per 10,000 person-years, P=0.04). CONCLUSIONS: Long-term total mortality after gastric bypass surgery was significantly reduced, particularly deaths from diabetes, heart disease, and cancer. However, the rate of death from causes other than disease was higher in the surgery group than in the control group.

Longitudinal Changes in Cardiac Structure and Function in Severe Obesity: 11-Year Follow-Up in the Utah Obesity Study.

Background Progressive cardiac remodeling and worsening myocardial function over time have been proposed as potential mediators of heart failure in obesity. Methods and Results We serially assessed cardiac structure and function in 254 subjects participating in a longitudinal study of obesity. Demographic, clinical, laboratory, and echocardiographic features were determined at baseline and 2-, 6-, and 11-year follow-up. We measured body mass index (BMI) exposure as the area under the curve of the BMI at each of the 4 visits. At enrollment, mean age of the subjects was 47 years, 79% were women, mean BMI was 44 kg/m2, 26% had diabetes mellitus, 48% had hypertension, and 53% had hyperlipidemia. Between baseline and 11 years, BMI increased by 1.1 and 0.3 kg/m2 in men and women, respectively. There were modest increases in left ventricular (LV) end-diastolic volume, LV mass, and left atrial volume, and significant decreases in early/late mitral diastolic flow velocity ratio and E wave deceleration time. However, there were no significant changes in LV ejection fraction or ratio of early mitral diastolic flow velocity/early mitral annular velocity, whereas right ventricular fractional area change increased. Significant predictors of the change in LV mass were male sex, baseline BMI, BMI area under the curve, and change in LV stroke volume, but not smoking, hypertension, or diabetes mellitus. Conclusions In long-standing, persistent severe obesity, there was evidence of cardiac remodeling over a period of 11 years, but no clear worsening of systolic or diastolic function. Measures of remodeling were most strongly related to BMI. The observed changes might predispose to heart failure with preserved ejection fraction, but are not classic for an evolving dilated cardiomyopathy.

Gut microbiota differs a decade after bariatric surgery relative to a nonsurgical comparison group.

BACKGROUND: Few studies have assessed differences in the gut microbiota composition after bariatric surgery in the long term or whether differences are correlated with remission of type 2 diabetes. OBJECTIVES: This observational study assessed differences in the gut microbiota between individuals at up to 13 years after surgery and a comparison group of individuals with severe obesity. The relationship between type 2 diabetes remission and the gut microbiota was also assessed. SETTING: University. METHODS: Stool samples were collected from individuals completing bariatric surgery (surgery group; n = 16) and individuals with severe obesity that did not receive surgery (nonsurgery group; n = 19) as part of the 12-year follow-up in the Utah Obesity Study. Metabolic health data were collected at baseline and the follow-up examination. The gut microbiota was quantified by sequencing the V4 region of the 16 S rRNA gene. Significant differences in microbiota composition with surgery and other covariates were determined by Unifrac distance analysis and permutational multivariate analysis of variance. Significant differences in the relative abundance of individual bacterial taxa were assessed using analysis of composition of microbiomes software. RESULTS: The surgery group had higher relative abundances of Verrucomicrobiaceae (5.7 ± 1.3% versus 1.1 ± .3%) and Streptococcaceae (6.3 ± 1.0% versus 3.2 ± .8%), but lower relative abundances of Bacteroidaceae (8.8 ± 1.8% versus 18.6 ± 2.3%) 10.6 years after surgery. In a small subset of 8 individuals, a higher relative abundance of Akkermansia muciniphila was correlated with type 2 diabetes remission. CONCLUSIONS: Differences in the gut microbiota are evident a decade after bariatric surgery compared with individuals with severe obesity that did not undergo surgery. The observed long-term differences are consistent with previous findings.

Cancer and obesity: effect of bariatric surgery.

Recent international cancer prevention guidelines recommend weight loss, where appropriate, for the purpose of cancer risk reduction. However, limited research associates voluntary weight loss to subsequent cancer incidence because of the difficulty of achieving long-term weight loss maintenance among large participant groups. Bariatric surgery has demonstrated long-term sustained weight loss, and as a result, patients after bariatric surgery represent an ideal population to explore the relationship between long-term, voluntary weight loss and cancer incidence. This paper briefly reviews cancers that have shown to be associated with overweight and obesity and looks at studies that demonstrate reduced total mortality after bariatric surgery. Reduced cancer mortality and incidence as well as reduced cancer-related physician visits after bariatric surgery are presented. Study limitations and future research questions related to cancer and bariatric surgery are briefly discussed.

Two-year changes in health-related quality of life in gastric bypass patients compared with severely obese controls.

BACKGROUND: Few weight loss surgery trials have evaluated the changes in health-related quality of life (HRQOL) relative to obese individuals not participating in weight loss interventions. In a prospective study at a bariatric surgery practice, we evaluated the 2-year changes in HRQOL in gastric bypass patients compared with 2 severely obese groups who did not undergo surgical weight loss. METHODS: A total of 308 gastric bypass patients were compared with 253 individuals who sought but did not undergo gastric bypass and 272 population-based obese individuals using the weight-related (Impact of Weight on Quality of Life-Lite) and general (Medical Outcomes Study 36-item Short-Form Health Survey) HRQOL questionnaires at baseline and 2 years of follow-up. RESULTS: The percentage of weight loss was 34.2% for the gastric bypass and 1.4% for the no gastric bypass groups, with a .5% gain for population-based obese group. Both measures of HRQOL showed greater improvements for the gastric bypass group, even after controlling for baseline differences. Effect sizes for changes in physical and weight-related HRQOL were very large for gastric bypass, but small to medium for the 2 comparison groups. Effect sizes for changes in the psychosocial aspects of HRQOL were moderate to very large for gastric bypass, but small for the 2 comparison groups. Of the gastric bypass patients, 97% had meaningful improvements in the Impact of Weight on Quality of Life-Lite total score compared with 43% of the no gastric bypass group and 30% of the population-based obese group. CONCLUSION: Dramatic improvements had occurred in weight-related and physical HRQOL for gastric bypass patients at 2 years after surgery compared with 2 severely obese groups who had not undergone surgery. These results support the effectiveness of gastric bypass surgery in improving patients' HRQOL.