- •Bariatric surgery is associated with cognitive improvements.
- •Improved liver function may contribute to post-surgery cognitive benefits.
- •Bariatric surgery may reduce dementia risk in obesity via better metabolic function.
The mechanisms for improved cognitive function post-bariatric surgery are not well understood. Markers of kidney and liver function (i.e., cystatin C and alkaline phosphatase (ALP)) are elevated in obese individuals and associated with poor neurocognitive outcomes in other samples. Bariatric surgery can improve cystatin C and ALP levels, but no study has examined whether such changes correspond to post-operative cognitive benefits.
78 bariatric surgery patients completed a computerized cognitive test battery prior to and 12-months after surgery. All participants underwent an eight-hour fasting blood draw to quantify cystatin C and ALP concentrations.
Cognitive function improved after surgery. Cystatin C levels decreased at the 12-month follow-up; however, no changes were found in ALP concentrations. At baseline, higher cystatin C levels predicted worse attention/executive function, but no such effects emerged for ALP. Regression analyses controlling for possible medical and demographic confounds and baseline factors revealed that decreased ALP levels following surgery predicted better attention/executive function and memory abilities. Post-surgery changes in cystatin C did not correspond to cognitive improvements.
Decreased ALP levels predicted better cognition following bariatric surgery, suggesting improved liver function as a possible mechanism of post-operative cognitive benefits. Future studies with neuroimaging and longer follow-up periods are needed to determine whether bariatric surgery can decrease risk for adverse brain changes and dementia in severely obese persons via improved metabolic function.
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- Improved memory function two years after bariatric surgery.Obesity (Silver Spring). 2014; 22: 32-38
- Cognitive function after bariatric surgery: evidence for improvement 3 years after surgery.Am J Surg. 2014; 207: 870-876
- Safety and efficacy of bariatric surgery: longitudinal assessment of bariatric surgery.Surg Obes Relat Dis. 2007; 3: 116-126
- Impact of body mass index on neuronal fiber bundle lengths among healthy older adults.Brain Imaging Behav. 2013; 7: 300-306
- Steatosis and hepatic markers before and shortly after bariatric surgery.Ann Clin Biochem. 2007; 44: 63-69
- Elevation of cystatin C in susceptible neurons in Alzheimer's disease.Am J Pathol. 2001; 159: 1061-1068
- Tissue-nonspecific alkaline phosphatase promotes the neurotoxicity effect of extracellular tau.J Biol Chem. 2010; 285: 32539-32548
- Functional impairment in alcoholic liver disease and non-alcoholic liver disease is significant and persists over 3 years of follow-up.Dig Dis Sci. 2013; 58: 2383-2391
- Practice effects associated with the repeated assessment of cognitive function using the CogState battery at 10-minute, one week and one month test–retest intervals.J Clin Exp Neuropsychol. 2006; 28: 1095-1112
- Effect of bariatric surgery-induced weight loss on renal and systemic inflammation and blood pressure: a 12-month prospective study.Surg Obes Relat Dis. 2013; 9: 559-568
- Areal and subcellular localization of the ubiquitous alkaline phosphatase in the primate cerebral cortex: evidence for a role in neurotransmission.Cereb Cortex. 2004; 14: 595-609
- Plasma cystatin C and risk of developing Alzheimer's disease in subjects with mild cognitive impairment.J Alzheimer Dis. 2010; 22: 985-991
- Heart disease and stroke statistics—2013 update: a report from the American Heart Association.Circulation. 2013; 127: e6-e245
- Elevated serum liver enzymes in obesity: a dilemma during clinical trials.Int J Obes. 1991; 15: 797-801
- Relationship between body mass index and brain volume in healthy adults.Int J Neurosci. 2008; 118: 1582-1593
- Improved memory function 12 weeks after bariatric surgery.Surg Obes Relat Dis. 2011; 7: 465-472
- Plasma alkaline phosphatase is elevated in Alzheimer's disease and inversely correlates with cognitive function.Int J Mol Epidemiol Genet. 2011; 2: 114-121
- The ectonucleotidases alkaline phosphatase and nucleoside triphosphate diphosphohydrolase 2 are associated with subsets of progenitor cell populations in the mouse embryonic, postnatal and adult neurogenic zones.Neuroscience. 2007; 150: 863-879
- Evidence of executive dysfunction in extremely obese adolescents: a pilot study.Surg Obes Relat Dis. 2009; 5: 547-552
- Bariatric surgery patients exhibit improved memory function 12 months post-operatively.Obes Surg. 2013; 23: 1527-1535
- Overweight, obesity, and elevated serum cystatin C levels in adults in the United States.Am J Med. 2008; 121: 341-348
- Preliminary validity of “integneuro” a new computerized battery of neurocognitive tests.Int J Neurosci. 2005; 115: 1549-1567
- Mapping creatinine- and cystatin C-related white matter brain deficits in the elderly.Neurobiol Aging. 2013; 34: 1221-1230
- Validity of the trail making test as an indicator of organic brain damage.Percept Mot Skills. 1958; 8: 271-276
- Cystatin C and subclinical brain infarction.J Am Soc Nephrol. 2005; 16: 3721-3727
- Cystatin C and the risk of death and cardiovascular events among elderly persons.N Engl J Med. 2005; 19: 2049-2060
- Body mass index and neurocognitive functioning across the adult lifespan.Neuropsychology. 2013; 27: 141-151
- Effects of laparoscopic Roux-en-Y gastic bypass (LRYGP) on weight loss and biomarker parameters in morbidly obese patients: a 12-month follow-up.Obes Surg. 2011; 21: 1834-1842
- Alkaline phosphatase is increased in both brain and plasma in Alzheimer's disease.Neurodegener Dis. 2012; 9: 31-37
- Interpretation and clinical significance of alkaline phosphatase isoenzyme patterns.Crit Rev Clin Lab Sci. 1994; 31: 197-293
- Alkaline phosphatase, serum phosphate, and incident cardiovascular disease and total mortality in older men.Areterioscler Thromb Vasc Biol. 2013; 33: 1070-1076
- Understanding brain damage — a primer of neuropsychological evaluation.Churchill Livingstone, Melbourne1985
- The test–retest reliability of a standardized neurocognitive and neurophysiological test battery: “neuromarker”.Int J Neurosci. 2005; 115: 1605-1630
- Midlife overweight and obesity increase late-life dementia risk: a population-based twin study.Neurology. 2011; 76: 1568-1574
- Cystatin C as a marker of cognitive function in elders: findings from the health ABC study.Ann Neurol. 2008; 63: 798-802
- Effects of intentional weight loss on physical and cognitive function in middle-aged and older obese participants: a pilot study.J Am Coll Nutr. 2012; 31: 79-86
Published online: July 22, 2014
Accepted: July 15, 2014
Received in revised form: June 25, 2014
Received: April 28, 2014
© 2014 Elsevier B.V. Published by Elsevier Inc. All rights reserved.