Cognitive function after bariatric surgery: evidence for improvement 3 years after surgery

doi:10.1016/j.amjsurg.2013.05.018

The American Journal of Surgery

Volume 207, Issue 6, June 2014, Pages 870-876

https://doi.org/10.1016/j.amjsurg.2013.05.018 Get rights and content

Abstract

Background

Bariatric surgery is associated with improved cognition, and it is possible that such improvements are found at extended follow-ups. We hypothesized that cognitive improvement would be maintained 3 years after bariatric surgery.

Methods

Fifty bariatric patients were recruited from the Longitudinal Assessment of Bariatric Surgery parent project. Participants completed a computerized cognitive test battery to assess cognitive function at 12 weeks, 12 months, 24 months, and 36 months after surgery.

Results

Repeated measures revealed main effects for attention, executive function, and memory. Attention improved up to 24 months and then slightly declined although it still fell within the average range at 36 months. Improvements in executive function reached their peak at 36 months after surgery. Short-term improvements in memory were maintained at 36 months. No main effect emerged for language.

Conclusions

Bariatric surgery may lead to lasting improvements in cognition. Prospective studies with extended follow-ups (eg, 10 years) should examine whether bariatric surgery can attenuate cognitive decline in severely obese patients.

Section snippets

Trial design and participants

A total of 50 consecutive bariatric patients were recruited into this multisite prospective study examining the neurocognitive effects of bariatric surgery. All participants were part of the Longitudinal Assessment of Bariatric Surgery (LABS) parent project and were recruited from 3 LABS sites.¹⁶ Patients participating in the parent project who were eligible for the current study were approached at the time of enrollment regarding this ancillary cognitive study. Greater than 80% of participants

Baseline and 36-month BMI and comorbid medical status

Based on conventional BMI categories, the current sample of bariatric surgery patients were classified as very severely obese at baseline (mean BMI = 46.61 [SD = 5.27]). However, the average BMI reduced to 32.35 (SD = 6.57) (ie, moderately obese) at 36 months, which represents a significant decline (Λ = .13, F_1,46 = 300.06, P < .001). A similar pattern emerged with comorbid medical status. Specifically, relative to baseline, significantly fewer participants had hypertension (chi-square₁ = 4.49,

Comments

The current study hypothesized that bariatric surgery patients would show postoperative improvements in cognitive function that would be maintained at a 36-month follow-up. Our findings support this hypothesis and extend previous work by showing the long-term cognitive benefits of bariatric surgery. Specifically, the current findings show that improvements in memory are maintained at 36 months postoperatively and further indicate that executive function improves up to this time point.

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Cognitive functioning in adolescents with severe obesity undergoing bariatric surgery or intensive non-surgical treatment in Sweden (AMOS2): a multicentre, open-label, randomised controlled trial
2024, eClinicalMedicine
Severe obesity during childhood is associated with cognitive deficits. Studies in adults have suggested improvements in executive functioning and memory after bariatric surgery. Our aim was to explore changes in cognitive function in adolescents over two years after bariatric surgery or intensive non-surgical treatment.
The Adolescent Morbid Obesity Surgery 2 (AMOS2) is a multicentre, open-label, randomised controlled trial in which adolescents (aged 13–16 years) with severe obesity (defined as body mass index (BMI) ≥35 kg/m²) at three specialised obesity centres in Sweden, were randomly assigned to receive bariatric surgery or intensive non-surgical treatment. Herein we report the results of the prespecified exploratory endpoint of change in cognitive functioning. Inclusion in AMOS2 required Tanner pubertal stage ≥3, previous participation in lifestyle obesity treatment for at least one year, and passed assessment form a paediatrician and a paediatric psychologist. Adolescents with severe intellectual disability or other severe, pervasive developmental disorder were excluded. Participants underwent baseline assessment of general intellectual ability, executive functioning, and memory before randomisation. Tests were administrated by clinical psychologists and repeated at one- and two-year follow-up timepoints. Differences in means between groups during follow-up are provided with confidence intervals. The trial is registered at ClinicalTrials.gov, NCT02378259.
Between October 28 2015 and June 7 2017, 46 adolescents (74% girls), with a mean age of 15.8 (±0.92) years and a mean BMI of 42.8 (±5.4) kg/m², were included and randomised (23 to bariatric surgery and 23 to intensive non-surgical treatment). At baseline 23/46 (50%) of the adolescents had general intellectual functioning classified as borderline or below. For 15/18 (83%) aspects of cognitive functioning, no significant differences in change over two years were identified between groups; Immediate (average difference during follow-up 1.0 [95% CI: −2.6 to 4.6]) and Delayed (0.5 [95% CI: −0.6 to 1.6]) Verbal Recall, Category Fluency (1.1 [95% CI: −1.6 to 3.8]) and Switching (1.5 [95% CI: −0.0 to 2.9]), Number (−6.0 [95% CI: −12.3 to 0.3]) and Letter (0.1 [95% CI: −5.2 to 5.3]) Sequencing, Number-Letter Switching (−10.3 [95% CI: −26.4 to 5.8]), Motor Speed (−8.3 [95% CI: −17.5 to 0.9]), Colour Naming (−1.9 [95% CI: −4.2 to 0.3]), Inhibition (−3.6 [95% CI: −9.6 to 2.5]), Inhibition Switching (−6.7 [95% CI: −15.3 to 1.9]), Mazes (−0.5 [95% CI: −4.9 to 3.9]), Digit Span Forward (0.1 [95% CI: −0.6 to 0.9 ]) and Backward (0.6 [95% CI: −0.4 to 1.6 ]), and Estimated IQ (0.4 [95% CI: −3.9 to 4.8]; all p > 0.05). Three sub-tests assessing fundamental cognitive skills improved more over two years in operated adolescents than in intensive non-surgical treatment; Letter Fluency (average difference during follow-up 3.8 [95% CI: 0.1–7.5]; p = 0.046), Visual Scanning (−6.5 [95% CI: −11.6 to −1.5]; p = 0.011), and Word Reading (−1.9 [95% CI: −3.3 to −0.4]; p = 0.011).
In contrast to non-randomised studies in adults, we could not demonstrate an association of bariatric surgery and its accompanying significant weight loss with overall greater improvement in executive functions and memory in adolescents over two years compared with a non-surgical group without weight loss. However, lack of statistical power is a potential limitation. The clinical relevance of greater improvements in basic cognitive skills needs to be explored.
Sweden's innovation agency (VINNOVA), Swedish Research Council, Joanna Cocozza foundation for paediatric research, The Skane University Hospital Psychology Research and Development Grant, Tore Nilsson’s Foundation, SUS Foundations and Donations, and Mary von Sydow’s Foundation.
Prevention of cardiorenal complications in people with type 2 diabetes and obesity
2024, Cell Metabolism
Traditional approaches to prevention of the complications of type 2 diabetes (T2D) and obesity have focused on reduction of blood glucose and body weight. The development of new classes of medications, together with evidence from dietary weight loss and bariatric surgery trials, provides new options for prevention of heart failure, chronic kidney disease, myocardial infarction, stroke, metabolic liver disease, cancer, T2D, and neurodegenerative disorders. Here I review evidence for use of lifestyle modification, SGLT-2 inhibitors, GLP-1 receptor agonists, selective mineralocorticoid receptor antagonists, and bariatric surgery, for prevention of cardiorenal and metabolic complications in people with T2D or obesity, highlighting the contributions of weight loss, as well as weight loss-independent mechanisms of action. Collectively, the evidence supports a tailored approach to selection of therapeutic interventions for T2D and obesity based on the likelihood of developing specific complications, rather than a stepwise approach focused exclusively on glycemic or weight control.
Cognitive function 10 years after adolescent bariatric surgery
2024, Surgery for Obesity and Related Diseases
Adolescent bariatric surgery produces substantial weight loss and reduction of medical co-morbidities. Research in adult samples shows improved cognitive function postoperatively, although much less is known about the potential cognitive benefits of bariatric surgery in adolescents—especially at extended follow-up.
Examine cognitive function 10 years after adolescent bariatric surgery.
University hospital.
A total of 99 young adults who underwent bariatric surgery as adolescents completed a computerized cognitive test battery as part of a larger 10-year postoperative assessment. All had been long-term participants in the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study.
Cognitive dysfunction was prevalent on tests of attention and executive function (e.g., Continuous Performance Test – Reaction Time 30%; Maze Errors – Overrun 30%), and 53.5% met research criteria for mild cognitive impairment (MCI). Modified Poisson regression with robust error variance revealed participants with preoperative hypertension and those completing Roux-en-Y gastric bypass were more likely to meet criteria for MCI at 10-year follow-up.
The current findings indicate that cognitive deficits are common 10 years after bariatric surgery. Additional studies are needed to clarify possible cohort effects, determine whether these cognitive deficits persist to even later follow-up (e.g., 20 yr after surgery), and identify underlying mechanisms and mitigation strategies.
Examining sex differences in the association between sedentary behavior and cognitive function in bariatric surgery patients
2023, Surgery for Obesity and Related Diseases
Obesity is associated with cognitive impairment. A potential contributor to these deficits is sedentary behavior (SB), which is linked to poorer cognitive functioning in other populations. Little is known about the association between SB and cognitive function in bariatric surgery populations.
This cross-sectional study examined the association between SB and cognitive function in preoperative bariatric surgery patients, as well as possible sex differences in this relationship.
Data were collected at 2 health centers in the United States.
A total of 121 participants (43.2 ± 10.3 yr of age) scheduled for Roux-en-Y gastric bypass or sleeve gastrectomy completed the National Institute of Health (NIH) Toolbox for the Assessment of Neurological and Behavioral Function Cognition Domain, a computerized neuropsychological assessment battery. Participants wore a waist-mounted accelerometer for 7 consecutive days to measure SB and light-intensity physical activity (LPA).
Pearson and partial correlations found no significant relationships between cognitive function and SB or LPA in the full sample. However, partial correlations controlling for LPA found that greater SB was associated with poorer performance on List Sorting Working Memory Test in women (r = −.28; P = .006), whereas there was a positive relationship between SB and Dimensional Change Card Sort for men (r = .51; P = .015; 95% CI [.25, .73]).
These results showed that greater SB, independent of LPA, is associated with poorer working memory in women and better set shifting ability in men. Future studies should examine the possibility of domain-specific cognitive effects associated with SB in bariatric surgery samples and clarify possible sex differences.
Effects of bariatric surgery on cognitive function in older adults: a prospective longitudinal study
2023, Surgery for Obesity and Related Diseases
Obesity is now well-recognized as an independent risk factor for cognitive decline. Although extensive research has been conducted on cognitive outcomes following bariatric surgery in young adults, very little is known about the impact of advanced age on the cognitive benefits of weight-loss procedures.
This study aimed to assess cognitive function in older Iranian patients before and after bariatric surgery.
University Hospital
In this prospective longitudinal study, 24 older adults were examined before and 4 months after bariatric surgery using the Digit Span Test (DGS), the computerized version of the Wisconsin Card Sorting Test-64 (WCST-64), and the paper-and-pencil versions of the Trail Making Test (TMT), parts A and B, spanning the 4 cognitive domains of attention, working memory, processing speed, and executive functioning. The bariatric surgery group was simultaneously compared to a waiting list control group.
At 4 months of follow-up, comparisons between the groups revealed that the surgical group performed significantly better than the control group on the forward DGS, WCST, and TMT parts A and B. In contrast, there was no significant difference between groups on the backward DGS. Further within-group comparisons demonstrated significant improvements from baseline in forward DGS, WCST, and TMT components A and B. Nevertheless, the same variables did not alter significantly over time in the control group.
The study suggests measurable cognitive benefits following bariatric surgery in older adults.
Distinct adaptations of endocrine and cognitive functions may contribute to high variability in long-term weight loss outcome after bariatric surgery
2023, Physiology and Behavior
Background: Bariatric surgery has been widely recognized as the most efficient long-term treatment method in severe obesity, yet therapy success shows considerable interindividual variability. Postoperative metabolic adaptations, including improved gut hormone secretion (GLP-1, PYY and ghrelin), and restored executive function may play an explanatory role in weight loss, yet causes for poor success in individual patients remain unknown. This study investigates gut-hormonal and cognitive characteristics in extreme weight loss responders to bariatric surgery. Methods: Patients (n = 47) with high or low excessive weight loss (EWL) at least 2 years after Roux-en-Y-gastric bypass or sleeve gastrectomy were allocated into good responders (GR, EWL 82.4 ± 11.6%) and poor responders (PR, EWL 24.0 ± SD 12.8%) to study differences in postprandial secretion of GLP-1, PYY, ghrelin and in working memory (WM). Results: Mean BMI was 47.1 ± 6.2 kg/m² in PR (n = 21) and 28.9 ± 3.1 kg/m² in GR (n = 26, p < 0.001). Fasted GLP-1 and PYY were comparable for GR and PR (p > 0.2) and increased strongly after a standardized test meal (300 kcal liquid meal) with a peak at 15 to 30 min. The increase was stronger in GR compared to PR (GLP-1, PYY: Time x Group p < 0.05). Plasma ghrelin levels already differed between groups at fasted state, showing significantly higher levels for GR (p < 0.05). Postprandially, ghrelin secretion was suppressed in both groups, but suppression was higher in GR (Time x Group p < 0.05). GR showed significantly higher WM scores than PR (p < 0.05). Postprandial ghrelin (iAUC), but not GLP-1 or PYY plasma levels, significantly mediated the relationship between EWL and a WM subscore (IS score, CI = 0.07 - 1.68), but not WM main score (MIS score, CI = -0.07 - 1.54), in mediation analyses. Conclusion: Excess weight loss success after bariatric surgical procedures is associated with distinct profiles of gut-hormones at fasted and postprandial state, and differences in working memory. Better working memory performance in GR might be mediated by higher postprandial reduction in ghrelin plasma levels. Future studies need to integrate longitudinal data, larger samples and more sensitive cognitive tests.

View all citing articles on Scopus

: Data collection supported by DK075119. Manuscript supported in part by HL089311.

: The authors declare no conflict of interest.

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Clinical ScienceCognitive function after bariatric surgery: evidence for improvement 3 years after surgery

Abstract

Background

Methods

Results

Conclusions

Section snippets

Trial design and participants

Baseline and 36-month BMI and comorbid medical status

Comments

Lancet

Surg Obes Relat Dis

Surg Obes Relat Dis

Compr Psychiatry

Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010

JAMA

The disease burden associated with overweight and obesity

JAMA

Midlife and late-life obesity and the risk of dementia: cardiovascular health study

Arch Neurol

Relationship between body mass index and brain volume in healthy adults

Int J Neurosci

Relation between body mass index and cognitive function in healthy middle-aged men and women

Neurology

Longitudinal examination of obesity and cognitive function: results from the Baltimore Longitudinal Study of Aging

Neuroepidemiology

Gastric bypass as treatment for obesity: trends, characteristics, and complications

Obes Res

Medicares search for effective obesity treatments: diets are not the answer

Am Psychol

Bariatric surgery: shedding the monetary weight of prescription costs in the managed care arena

Obes Surg

The impact of weight reduction surgery on health care costs in morbidly obese patients

Obes Surg

Overview of outcomes of laparoscopic and open roux-en-Y gastric bypass in the United States

Surg Technol Int

Improved memory function two years after bariatric surgery

Obesity (Silver Spring)

Clinical Science
Cognitive function after bariatric surgery: evidence for improvement 3 years after surgery