Bariatric Surgery Linked to Lower Dementia, Parkinson's Risk

TOPLINEAmong individuals with a BMI of 35 or above, those who underwent bariatric surgery had a lower incidence of dementia and Parkinson's disease than those who did not undergo bariatric surgery. Bariatric surgery was also linked to a lower incidence of cardiovascular disease (CVD), obesity-associated cancers, and all-cause mortality.METHODOLOGYUsing data from the TriNetX network, researchers conducted a retrospective, observational cohort study to assess whether bariatric surgery was associated with the incidence of dementia and Parkinson's disease.They included 32,552 individuals with at least one recorded BMI of 35 or above who underwent bariatric surgery (mean age at the index date, 42.1 years; 82.4% female individuals) between 2005 and 2022. Using propensity score matching, they were matched with 32,552 individuals who did not undergo bariatric surgery (mean age at the index date, 42.5 years; 82.5% female individuals).The median follow-up duration was 4.7 years for individuals who underwent bariatric surgery and 5.9 years for those who did not.Incidences of dementia and Parkinson's disease were compared between individuals who underwent bariatric surgery and those who did not.Incidences of Alzheimer's disease, vascular dementia, CVD, obesity-associated cancers, and all-cause mortality were also compared between the two groups.TAKEAWAYIndividuals who underwent bariatric surgery had a lower incidence of dementia (hazard ratio [HR], 0.48; 95% CI, 0.39-0.58) and Parkinson's disease (HR, 0.70; 95% CI, 0.51-0.96) than those who did not undergo surgery.The incidence of Alzheimer's disease (HR, 0.58; 95% CI, 0.38-0.88) and vascular dementia (HR, 0.27; 95% CI, 0.15-0.48) was also lower among those who underwent bariatric surgery than among those who did not.Bariatric surgery was associated with a lower incidence of CVD (HR, 0.53; 95% CI, 0.51-0.56), obesity-associated cancers (HR, 0.66; 95% CI, 0.60-0.72), and all-cause mortality (HR, 0.46; 95% CI, 0.41-0.51).Individuals who underwent bariatric surgery and those who did not undergo surgery had 20-year survival probabilities of 84.7% and 81.8%, respectively.IN PRACTICE"[The study] results extend the known benefits of surgical WL [weight loss] into the domain of neurodegenerative disease prevention and align with prior research on the cardiometabolic and oncologic benefits of BS [bariatric surgery]," the authors wrote.SOURCEThis study was led by Suhail I. Shiekh, Diabetes Research Centre, Leicester General Hospital, College of Life Sciences, University of Leicester, Leicester, UK. It was published online on October 07, 2026, in the International Journal of Obesity.LIMITATIONSThe study included individuals who had a healthcare visit up to 6 months following a BMI reading of 35 or above, which may have introduced selection bias. The observational design limited the ability to draw causal inference. Baseline diabetes medications such as metformin and GLP-1 receptor agonists were not adjusted for as these medications may be modified due to bariatric surgery and metabolic changes.DISCLOSURESThis study received funding from the University of Leicester's College of Life Sciences PhD Studentship Scheme. Some authors declared receiving honorarium/advisory fees, grants, or funding and/or serving as paid consultants, speakers, or advisory board members of various pharmaceutical and biopharmaceutical companies or other sources. One author reported being a former employee of TriNetX and worked for the company when the study was conducted.This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.