Validity of dual-energy x-ray absorptiometry for estimation of visceral adipose tissue and visceral adipose tissue change after surgery-induced weight loss in women with severe obesity.

OBJECTIVE: Reliable and simple methods to quantify visceral adipose tissue (VAT) and VAT changes are needed. This study investigated the validity of dual-energy x-ray absorptiometry (DXA) compared with magnetic resonance imaging (MRI) for estimating VAT cross sectionally and longitudinally after surgery-induced weight loss in women with severe obesity. METHODS: Women with obesity (n = 36; mean age 43 [SD 10] years; 89% White) with DXA and MRI before bariatric surgery (T0) at 12 (T12) and 24 months (T24) post surgery were included. CoreScan (GE Healthcare, Chicago, Illinois) estimated VAT from 20% of the distance between the top of the iliac crest and the base of the skull. MRI VAT (total VAT) was measured from the base of the heart to the sacrum/coccyx on a whole-body scan. RESULTS: Mean DXA VAT was 45% of MRI VAT at T0, 46% at T12, and 68% at T24. DXA underestimated change in MRI VAT between T0 and T12 by 26.1% (0.81 kg, p = 0.03) and by 71.7% (0.43 kg, p < 0.001) between T12 and T24. The relationship between DXA VAT and MRI VAT differed between T12 and T24 (p value for interaction = 0.03). CONCLUSIONS: CoreScan lacks validity for comparing VAT across individuals or for estimating the size of changes within individuals; however, within the limits of measurement error, it may provide a useful indicator of whether some VAT change has occurred within an individual.

Weight loss after bariatric surgery in cancer survivors.

BACKGROUND: With improved methods of identification and treatment, the numbers of cancer survivors are increasing. Weight loss is encouraged to reduce recurrence. After cancer treatment, will survivors respond to weight change and receive the benefits of bariatric surgery? OBJECTIVE: To compare weight loss after bariatric surgery of patients treated for cancer with those never diagnosed with cancer. SETTING: The 10 surgical centers participating in the Longitudinal Assessment of Bariatric Surgery (LABS2). METHODS: A retrospective review of the LABS database of 2458 participants was completed to determine which patients had answered the question that they had been told they had cancer with a positive response. Cancer survivors were compared for body mass index (calculated as weight in kilograms divided by height in meters squared) at baseline and 1, 3, 5, and 7 years after bariatric surgery with those who responded negatively to this question. Descriptive statistics, Fisher's exact tests, 2-sample independent t tests, Wilcoxon rank sum tests, and multiple linear regression were used. RESULTS: Groups were significantly different in age (P < .0001) and surgery type (P = .02). Other demographic and clinical comparisons were nonsignificant at the .05 significance level. Cancer survivors demonstrated less weight loss at 1 year (P = .0001). Over 7 years, there was no significant difference between the 2 groups. Adjusting for age, sex, baseline body mass index, and surgery type, cancer history was not found to be significant predictor of body mass index change 1-year postbariatric surgery. CONCLUSIONS: Patients treated for cancer are not different than the general population in their capacity for long-term weight loss with surgical assistance.

Resting Energy Expenditure and Organ-Tissue Body Composition 5 Years After Bariatric Surgery.

INTRODUCTION: Bariatric surgery-induced weight loss may reduce resting energy expenditure (REE) and fat-free mass (FFM) disproportionately thereby predisposing patients to weight regain and sarcopenia. METHODS: We compared REE and body composition of African-American and Caucasian Roux-en-Y gastric bypass (RYGB) patients after surgery with a group of non-operated controls (CON). REE by indirect calorimetry; skeletal muscle (SM), trunk organs, and brain volumes by MRI; and FFM by DXA were measured at post-surgery visits and compared with CON (N = 84) using linear regression models that adjusted for relevant covariates. Ns in RYGB were 50, 42, and 30 for anthropometry and 39, 27, 17 for MRI body composition at years 1, 2, and 5 after surgery, respectively. RESULTS: Regression models adjusted for age, weight, height, ethnicity, and sex showed REE differences (RYGB minus CON; mean ± s.e.): year 1 (43.2 ± 34 kcal/day, p = 0.20); year 2 (- 27.9 ± 37.3 kcal/day, p = 0.46); year 5 (114.6 ± 42.3 kcal/day, p = 0.008). Analysis of FFM components showed that RYGB had greater trunk organ mass (~ 0.4 kg) and less SM (~ 1.34 kg) than CON at each visit. REE models adjusted for FFM, SM, trunk organs, and brain mass showed no between-group differences in REE (- 15.9 ± 54.8 kcal/day, p = 0.8; - 46.9 ± 64.9 kcal/day, p = 0.47; 47.7 ± 83.0 kcal/day, p = 0.57, at years 1, 2, and 5, respectively). CONCLUSIONS: Post bariatric surgery patients maintain a larger mass of high-metabolic rate trunk organs than non-operated controls of similar anthropometrics. Interpreting REE changes after weight loss requires an accurate understanding of fat-free mass composition at both the organ and tissue levels. CLINICAL TRIAL REGISTRATION: Long-term Effects of Bariatric Surgery (LABS-2) NCT00465829.

The impact of bariatric surgery on asthma control differs among obese individuals with reported prior or current asthma, with or without metabolic syndrome.

BACKGROUND: Both obesity and the metabolic syndrome have been independently associated with increased asthma morbidity. However, it is unclear whether metabolic syndrome limits the beneficial effects of weight loss on asthma. OBJECTIVES: To evaluate whether bariatric weight loss is associated with improved asthma control, and whether this association varies by metabolic syndrome status. METHODS: We determined the changes in asthma control, defined by the Asthma Control Test (ACT), before and after bariatric surgery among participants with asthma in the multi-center Longitudinal Assessment of Bariatric Surgery (LABS) study, stratifying our analysis by the presence or absence of metabolic syndrome. RESULTS: Among 2,458 LABS participants, 555 participants had an asthma diagnosis and were included in our analysis. Of these, 78% (n = 433) met criteria for metabolic syndrome (MetSyn) at baseline. In patients without MetSyn, mean ACT increased from 20.4 at baseline to 22.1 by 12-24 months, ending at 21.3 at 60 months. In contrast, among those with MetSyn there was no significant improvement in ACT scores. The proportion of patients without MetSyn with adequate asthma control (ACT >19) increased from 58% at baseline to 78% and 82% at 12 and 60 months, respectively, whereas among those with MetSyn, it was 73.8% at baseline, 77.1% at 12 months, dropping to 47.1% at 60 months (p = 0.004 for interaction between metabolic syndrome and time). Having MetSyn also increased the likelihood of losing asthma control during follow-up (HR = 1.92, 95% confidence interval [CI] 1.24-2.97, p = 0.003). CONCLUSIONS: Metabolic syndrome may negatively modify the effect of bariatric surgery-induced weight loss on asthma control.

Changes in Sexual Functioning in Women and Men in the 5 Years After Bariatric Surgery.

Importance: Short-term improvements in sexual functioning are reported after bariatric surgery, but to our knowledge, little is known about the durability of these improvements. Objective: To determine the percentage of adults with impairment in sexual functioning who experience durable improvements in sexual functioning after bariatric surgery and to identify factors associated with improvements. Design, Setting, and Participants: The Longitudinal Assessment of Bariatric Surgery-2 is an observational cohort study conducted at 10 hospitals in 6 US clinical centers. Adults undergoing their first bariatric procedure were recruited from 2005 through 2009, data were collected through August 2014. Data analysis was conducted from 2016 to April 2018. Interventions: Participants completed assessments before the procedure and annually thereafter for 5 years. Main Outcomes and Measures: A self-administered questionnaire was used to assess clinically meaningful differences before and after surgery in past-month sexual satisfaction, desire, and activity and physical health limitations to sexual activity among subgroups who reported sexual functioning at less than domain-specific thresholds before surgery. Results: Of 2215 participants eligible for sexual function follow-up, 2036 (91.9%) completed 1 or more follow-up assessment (1431 [64.6%] at year 5), of whom 1607 (78.9%) were women. At the presurgery assessment, median (interquartile range) age was 47 (37-55) years, and the median (interquartile range) body mass index was 45.8 (41.7-51.3). Among those who were not satisfied with their sexual life before surgery (1015 of 1456 women [69.7%]; 304 of 409 men [74.3%]), 56.0% of women (95% CI, 52.5%-59.5%) and 49.2% of men (95% CI, 42.4%-55.9%) experienced clinically meaningful improvements at year 1; these percentages did not significantly differ during further follow-up. Among those who reported physical limitations to sexual activity at baseline (892 of 1490 women [59.9%] and 267 of 406 men [65.8%]), the percentage experiencing improvement in this domain decreased during follow-up, but 73.6% (95% CI, 69.3%-78.0%) of women and 67.6% (95% CI, 59.6%-75.6%) of men continued to report improvements at year 5. Greater postsurgical reduction in depressive symptoms was independently associated with improvement in 4 domains of sexual life among women (frequency of sexual desire: adjusted relative risk [aRR] per 5-point decrease in Beck Depression Inventory score, 1.12 [95% CI, 1.07-1.18]; P < .001; frequency of sexual activity: aRR, 1.13 [95% CI, 1.08-1.18]; P < .001; the degree to which physical health limited sexual activity: aRR, 1.19 [95% CI, 1.14-1.23]; P < .001; and satisfaction with sexual life: aRR, 1.25 [95% CI, 1.19-1.31]; P < .001) and 2 domains among men (physical health limitations: aRR, 1.14 [95% CI, 1.04-1.26]; P = .008 and satisfaction with sexual life: aRR, 1.55 [95% CI, 1.33-1.81]; P < .001). Surgical procedure was not associated with improvement. Conclusions and Relevance: Per this study, approximately half of women and men who were not satisfied with their sexual life prior to bariatric surgery experienced improvements in satisfaction in 5 years of follow-up. Trial Registration: ClinicalTrials.gov Identifier: NCT00465829.

Fat-Free Mass and Skeletal Muscle Mass Five Years After Bariatric Surgery.

OBJECTIVE: This study investigated changes in fat-free mass (FFM) and skeletal muscle 5 years after surgery in participants from the Longitudinal Assessment of Bariatric Surgery-2 trial. METHODS: A three-compartment model assessed FFM, and whole-body magnetic resonance imaging (MRI) quantified skeletal muscle mass prior to surgery (T0) and 1 year (T1), 2 years (T2), and 5 years (T5) postoperatively in 93 patients (85% female; 68% Caucasian; age 44.2 ± 11.6 years) who underwent gastric bypass (RYGB), sleeve gastrectomy, or adjustable gastric band. Repeated-measures mixed models were used to analyze the data. RESULTS: Significant weight loss occurred across all surgical groups in females from T0 to T1. FFM loss from T0 to T1 was greater after RYGB (mean ± SE: -6.9 ± 0.6 kg) than adjustable gastric band (-3.5 ± 1.4 kg; P < 0.05). Females with RYGB continued to lose FFM (-3.3 ± 0.7 kg; P < 0.001) from T1 to T5. A subset of males and females with RYGB and MRI-measured skeletal muscle showed similar initial FFM loss while maintaining FFM and skeletal muscle from T1 to T5. CONCLUSIONS: Between 1 and 5 years following common bariatric procedures, FFM and skeletal muscle are maintained or decrease minimally. The changes observed in FFM and muscle during the follow-up phase may be consistent with aging.

Nutrient Status 9 Years After Biliopancreatic Diversion with Duodenal Switch (BPD/DS): an Observational Study.

BACKGROUND: Since biliopancreatic diversion with duodenal switch (BPD/DS) produces hypoabsorption, evaluation of long-term nutrient changes is appropriate. METHODS: Measurements of micronutrients, trace elements, PTH, iron studies, and protein were completed for consented patients at baseline prior to surgery and at yearly intervals. The patients were advised and supplements were adjusted by blood studies with compliance checks. Independent t tests and ANOVAs compared changes between cross-sectional cohorts based on follow-up time from surgery. A p value of 0.05 was considered significant. RESULTS: Between 1999 and 2010, 284 patients had BPD/DS. At baseline, nutrient analysis was available for only 190 patients (70% women), age 42.7 ± 10.0 years, BMI 53.0 ± 11.9 kg/m2; at year 1, 189 were available; at year 3, 193; at year 5, 132; at year 7, 98; and at year 9, 68. Gender distribution was not significantly different between cohorts. Baseline vitamin D was low and PTH high. All of the patients took some supplements. Fat-soluble vitamins remained low. Protein deficiency appeared at year 3 and increased to 30% at year 9. Baseline zinc was normal, but at year 5, 45% were low. Over time, hematocrit was low for 40% and hemoglobin for 46%. Iron deficiency continued through year 9, more marked in males. Calcium deficiency increased from year 3 and remained steady. Half of the patients had abnormal PTH at baseline, and the percentage increased over time. Twenty percent had abnormal baseline magnesium values. Magnesium fluctuated during observation. CONCLUSIONS: Major deficits in nutrient status occurred and persisted after surgery although supplementation was prescribed. Interventions are mandated to avoid nutrient deficiency.

Fat-free mass is not lower 24 months postbariatric surgery than nonoperated matched controls.

OBJECTIVE: Concerns about an excessive loss of fat-free mass (FFM) after bariatric surgery prompted this comparison of operated versus matched nonoperated controls regarding FFM. SETTING: University Hospital and University Research Unit in an urban medical center. METHODS: Body composition with bioelectric impedance (Tanita 310, Tanita Corp, Arlington Heights, IL) was measured approximately 2 years after bariatric surgery in weight stable patients and nonoperated weight stable controls matched for body mass index (BMI), gender, and age. t tests provided comparisons. Analysis of variance was used to compare FFM changes for 4 procedures. Levene's test evaluated variance. RESULTS: Patients (n = 252; 24.7±15 mo after surgery) and nonoperated controls (n = 252) were matched for gender (71.8% female), age (44.5±11.0 yr), and BMI (32.8±7.0 kg/m2). Patients had different surgical procedures: 107 gastric bypasses (RYGBs), 62 biliopancreatic diversions with duodenal switch (BPD/DSs), 40 adjustable gastric bands (AGBs), and 43 sleeve gastrectomies (LSGs). FFM percentage was significantly higher in the operated patients than controls, 66% versus 62%, P<.0001. For 3 procedures, the FFM was significantly higher; however, AGBs changed only 7.3 BMI units and FFM was not significantly different from their matched controls, 59.8% versus 58.2%. Across surgical groups, FFM percentage differed, P<.0001 (RYGB 66.5±9.2%, BPD/DS 74.0±9.3%, AGB 59.8±7.0%, LSG 59.6±9.3%). Variance was not different (P = .17). CONCLUSION: Weight-reduced bariatric surgery patients have greater FFM compared with nonoperated matched controls. These findings support surgically assisted weight loss as a physiologic process and in general patients do not suffer from excessive FFM depletion after bariatric procedures.

Sexual functioning of men and women with severe obesity before bariatric surgery.

BACKGROUND: Obesity may impair sexual function through multiple mechanisms, but little is known about sexual dysfunction among adults with severe obesity seeking bariatric procedures. OBJECTIVES: To describe sexual function and associated factors before bariatric surgery. SETTING: Ten U.S. clinical facilities. METHODS: Before bariatric surgery, 2225 of 2458 Longitudinal Assessment of Bariatric Surgery-2 study participants (79% female, median age 45 years and median body mass index 46 kg/m2) completed a survey about sexual function over the past month. Mixed effects ordinal logistic regression models were used to identify factors independently related to 4 domains of sexual function. RESULTS: One third of women (34%) and one quarter of men (25%) were not sexually active, alone or with a partner, in the past month. Twenty-six percent of women and 12% of men reported no sexual desire. Physical health limited sexual activity at least moderately in 38% of women and 44% of men. About one half of the women (49%) and the men (54%) were moderately or very dissatisfied with their sexual life. Among women, older age, being Caucasian, urinary incontinence, depressive symptoms, and antidepressant medication use were associated with poorer sexual function in multiple domains. In men, older age, not being married, depressive symptoms, and antidepressant medication use were associated with poorer sexual function in multiple domains. CONCLUSION: Before bariatric surgery, approximately one half of women and men with severe obesity are dissatisfied with their sexual life. Older age, severity of depressive symptoms, and antidepressant medication use are associated with poorer sexual function in both sexes.

The Impact of Biliopancreatic Diversion with Duodenal Switch (BPD/DS) Over 9 Years.

BACKGROUND: There is limited information on the multiple long-term effects of the biliopancreatic diversion with duodenal switch (BPD/DS). METHODS: Patients who consented to a BPD/DS from 1999 to 2010 were evaluated for weight change, complications, comorbidity resolution, body composition, quality of life, and depressive symptoms during visits at 1, 3,5, 7, and 9 years. Descriptive statistics, analysis of variance, and pair-wise comparisons were calculated for each of the five follow-up cohorts vs. the baseline cohort. RESULTS: Between 1999 and 2010, 284 patients received a BPD/DS; 275 patients (69.8 % women) age 42.7 years, BMI 53.4 kg/m2 qualified for baseline analysis. Two hundred seventy-five patients were available in year 1; 275 patients in year 3; 273 patients in year 5; 259 patients in year 7; and 228 patients in year 9. Gender distribution was not different. BMI was 30.1 at 1 year and 32.0 at 9 years. Body fat was reduced to 26 % after 2 years. Complications requiring surgery were significant. Nutritional problems developed in 29.8 % of patients over the course of observation. The baseline Beck Depression Index (BDI) was 13.9 and 7.2 in year 1. Year 1 through 9 remained unchanged. There were significant positive changes in quality of life between baseline and year 1 for most domains. These positive changes were maintained for the follow-up cohorts. After surgery the resolution of comorbidities continued for the 9 years. CONCLUSIONS: Weight loss during the first year was well maintained, resolving comorbidities and improving quality of life. Rates of surgical complications resemble other bariatric procedures. Long-term nutrient deficiencies are of concern.

Mild cognitive impairment is prevalent in persons with severe obesity.

OBJECTIVE: This study examines the prevalence of mild cognitive impairment (MCI) in a sample of adults with severe obesity and whether undergoing bariatric surgery reduces the frequency of MCI. METHODS: A total of 171 participants with severe obesity (mean age = 43.07 ± 11.21) completed computerized cognitive testing. A subset of participants underwent bariatric surgery as part of the Longitudinal Assessment of Bariatric Surgery project. MCI was operationalized using commonly used criteria to establish prevalence in the overall sample and to examine possible changes after bariatric surgery. RESULTS: More than half of the overall sample met criteria for MCI at baseline (53.8%), and MCI was prevalent even in young and middle-aged adults with severe obesity. Within the subset of participants who underwent bariatric surgery, the prevalence of MCI was reduced by 48.9% at 12-month follow-up (from 53.4% to 27.3%). CONCLUSIONS: Findings suggest that many individuals with severe obesity meet criteria for MCI and that prevalence rates decline after bariatric surgery. A better understanding of the mechanisms linking severe obesity to adverse neurological outcomes is much needed.

Adolescent weight history and adult cognition: before and after bariatric surgery.

BACKGROUND: Cognitive deficits occur in a subset of individuals with obesity. Deficits can be reversed with bariatric surgery, though cognitive recovery is not equally exhibited across patients. Recent work has found that obesity during adolescence portends medical complications in adulthood; it is unknown if obesity in adolescence predicts adult cognition or cognitive recovery after weight loss surgery. OBJECTIVES: The present study examines the relationship between weight history and cognitive function in obese adults undergoing bariatric surgery. SETTING: Academic medical centers with bariatric care services. METHODS: Seventy-eight bariatric surgery patients (mean age = 43.2 years) enrolled in an ancillary study to the Longitudinal Assessment of Bariatric Surgery (LABS) project completed a questionnaire recalling weight history at age 18. Cognitive testing was completed preoperatively and at 12-month follow-up. RESULTS: Weight status at age 18 was linked to performance in several aspects of cognition. Higher body mass index at age 18 predicted poorer preoperative verbal fluency (B = -.26, P = .045) as well as postoperative cognitive recovery in attention (B = -.30, P = .01) at 12-month follow-up. CONCLUSION: Higher body mass index at age 18 predicts verbal fluency performance in adults with obesity, as well as postoperative recovery of attention after bariatric surgery. The mechanisms underlying this connection are not fully clear, though findings may reflect effects of obesity on the brain during a crucial period of neural maturation or duration of obesity and cumulative impact of co-morbidities on cognition. Future work examining possible causal factors involved in these relationships is needed.

Urinary Incontinence Before and After Bariatric Surgery.

IMPORTANCE: Among women and men with severe obesity, evidence for improvement in urinary incontinence beyond the first year after bariatric surgery-induced weight loss is lacking. OBJECTIVES: To examine change in urinary incontinence before and after bariatric surgery and to identify factors associated with improvement and remission among women and men in the first 3 years after bariatric surgery. DESIGN, SETTING, AND PARTICIPANTS: The Longitudinal Assessment of Bariatric Surgery 2 is an observational cohort study at 10 US hospitals in 6 geographically diverse clinical centers. Participants were recruited between February 21, 2005, and February 17, 2009. Adults undergoing first-time bariatric surgical procedures as part of clinical care by participating surgeons between March 14, 2006, and April 24, 2009, were followed up for 3 years (through October 24, 2012). INTERVENTION: Participants undergoing bariatric surgery completed research assessments before the procedure and annually thereafter. MAIN OUTCOMES AND MEASURES: The frequency and type of urinary incontinence episodes in the past 3 months were assessed using a validated questionnaire. Prevalent urinary incontinence was defined as at least weekly urinary incontinence episodes, and remission was defined as change from prevalent urinary incontinence at baseline to less than weekly urinary incontinence episodes at follow-up. RESULTS: Of 2458 participants, 1987 (80.8%) completed baseline and follow-up assessments. At baseline, the median age was 47 years (age range, 18-78 years), the median body mass index was 46 kg/m2 (range, 34-94 kg/m2), and 1565 of 1987 (78.8%) were women. Urinary incontinence was more prevalent among women (49.3%; 95% CI, 46.9%-51.9%) than men (21.8%; 95% CI, 18.2%-26.1%) (P < .001). After a mean 1-year weight loss of 29.5% (95% CI, 29.0%-30.1%) in women and 27.0% (95% CI, 25.9%-28.6%) in men, year 1 urinary incontinence prevalence was significantly lower among women (18.3%; 95% CI, 16.4%-20.4%) and men (9.8%; 95% CI, 7.2%-13.4%) (P < .001 for all). The 3-year prevalence was higher than the 1-year prevalence for both sexes (24.8%; 95% CI, 21.8%-26.5% among women and 12.2%; 95% CI, 9.0%-16.4% among men) but was substantially lower than baseline (P < .001 for all). Weight loss was independently related to urinary incontinence remission (relative risk, 1.08; 95% CI, 1.06-1.10 in women and 1.07; 95% CI, 1.02-1.13 in men) per 5% weight loss, as were younger age and the absence of a severe walking limitation. CONCLUSIONS AND RELEVANCE: Among women and men with severe obesity, bariatric surgery was associated with substantially reduced urinary incontinence over 3 years. Improvement in urinary incontinence may be an important benefit of bariatric surgery.

Bariatric surgery in cancer survivorship: does a history of cancer affect weight loss outcomes?

BACKGROUND: Weight loss is recommended for obese cancer survivors who are at increased risk of recurrence and non-cancer-related mortality. It remains unknown if this vulnerable population benefits from bariatric surgery to the same extent as those without a history of cancer. METHODS: A retrospective chart review of 1013 patients identified 29 bariatric surgery patients with a history of cancer who were then matched to patients without a history of cancer. RESULTS: At 1-year postsurgical follow-up, individuals with a history of cancer had lost less weight than those without a history of cancer (14.2 versus 14.8); however, this difference was not significant (P = .76). CONCLUSION: Cancer survivors appear to draw similar benefit from bariatric surgery as those without a history of cancer, although a larger study with greater statistical power to detect differences is needed to confirm these results. These preliminary results are encouraging in light of the increasing focus on weight loss among this population.

Glucose regulation and cognitive function after bariatric surgery.

INTRODUCTION: Obesity is associated with cognitive impairment, and bariatric surgery has been shown to improve cognitive functioning. Rapid improvements in glycemic control are common after bariatric surgery and likely contribute to these cognitive gains. We examined whether improvements in glucose regulation are associated with better cognitive function following bariatric surgery. METHOD: A total of 85 adult bariatric surgery patients underwent computerized cognitive testing and fasting blood draw for glucose, insulin, and glycated hemoglobin (HbA1c) at baseline and 12 months postoperatively. RESULTS: Significant improvements in both cognitive function and glycemic control were observed among patients. After controlling for baseline factors, 12-month homeostatic model assessment of insulin resistance HOMA-IR predicted 12-month digits backward (ß = -.253, p < .05), switching of attention-A (ß = .156, p < .05), and switching of attention-B (ß = -.181, p < .05). Specifically, as HOMA-IR decreased over time, working memory, psychomotor speed, and cognitive flexibility improved. Decreases in HbA1c were not associated with postoperative cognitive improvements. After controlling for baseline cognitive test performance, changes in body mass index (BMI) were also not associated with 12-month cognitive function. CONCLUSIONS: Small effects of improved glycemic control on improved aspects of attention and executive function were observed following bariatric surgery among severely obese individuals. Future research is needed to identify the underlying mechanisms for the neurocognitive benefits of these procedures.

Improved serum leptin and ghrelin following bariatric surgery predict better postoperative cognitive function.

BACKGROUND AND PURPOSE: Bariatric surgery is associated with improved cognitive function, but the mechanisms underlying these gains remain poorly understood. Disturbed leptin and ghrelin systems are common in obese individuals and are associated with impaired cognitive function in other samples. Bariatric surgery has been shown to improve serum leptin and ghrelin levels, and these changes may underlie postoperative cognitive improvements. METHODS: Eighty-four patients completed a computerized cognitive test battery prior to bariatric surgery and at 12 months postoperatively. Participants also submitted to an 8-hour fasting blood draw to quantify serum leptin and ghrelin concentrations at these same time points. RESULTS: Baseline cognitive impairments and disturbed leptin and ghrelin levels improved at the 12-month follow-up compared to presurgery. Higher leptin levels were associated with worse attention/executive function at baseline; no such findings emerged for ghrelin. Regression analyses controlling for baseline factors and demographic characteristics showed that both decreased leptin and increased ghrelin following surgery was associated with better attention/executive function at the 12-month follow-up. These effects diminished after controlling for the postoperative change in body mass index (BMI); however, BMI change did not predict 12-month cognitive function. CONCLUSIONS: Improvements in leptin and ghrelin levels following bariatric surgery appear to contribute to postoperative cognitive benefits. These gains may involve multiple mechanisms, such as reduced inflammation and improved glycemic control. Future studies that employ neuroimaging are needed to clarify the underlying mechanisms and determine whether the effects of bariatric surgery on leptin and ghrelin levels can attenuate adverse brain changes and/or risk of dementia in severely obese individuals.