title: Improved serum leptin and ghrelin following bariatric surgery predict better postoperative cognitive function.
abstract: OBJECTIVE
  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.
authors: Department of Psychology, Kent State University, Kent, OH, USA.
authors: Michael L
authors: ML
authors: Alosco
authors: Department of Psychology, Kent State University, Kent, OH, USA.
authors: Mary Beth
authors: MB
authors: Spitznagel
authors: Department of Surgery, Weill Cornell Medical College, New York, NY, USA.
authors: Gladys
authors: G
authors: Strain
authors: College of Physician's and Surgeons, Columbia University Medical Center, New York, NY, USA.
authors: Michael
authors: M
authors: Devlin
authors: Institute on Aging, Department of Aging & Geriatric Research, University of Florida Institute on Aging, Gainesville, FL, USA.
authors: Ronald
authors: R
authors: Cohen
authors: Neuropsychiatric Research Institute, University of North Dakota School of Medicine and Health Sciences, Fargo, ND, USA.
authors: Ross D
authors: RD
authors: Crosby
authors: Neuropsychiatric Research Institute, University of North Dakota School of Medicine and Health Sciences, Fargo, ND, USA.
authors: James E
authors: JE
authors: Mitchell
authors: Department of Psychology, Kent State University, Kent, OH, USA.
authors: John
authors: J
authors: Gunstad
keywords: bariatric surgery; cognitive function; ghrelin; leptin; obesity
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