UK: A study published in the International Journal of Obesity has found that bariatric surgery was associated with a lower incidence of dementia and Parkinson’s disease among individuals with a body mass index (BMI) of 35 kg/m² or higher. The procedure was also linked to reduced risks of cardiovascular disease, obesity-associated cancers, and all-cause mortality.

The study was conducted by Suhail I. Shiekh, Leicester Real World Evidence Unit, Diabetes Research Centre, College of Life Sciences, University of Leicester, Leicester, UK, and colleagues. The findings suggest that bariatric surgery may offer health benefits beyond weight loss, including a potential protective association against neurodegenerative diseases in people with obesity.
For the study, the researchers examined electronic health records from the TriNetX network to investigate the relationship between bariatric surgery and the subsequent development of dementia and Parkinson’s disease. They also assessed outcomes related to cardiovascular disease, obesity-associated cancers, and overall mortality.
The longitudinal cohort study included individuals aged 16 or older with at least one recorded BMI measurement of 35 kg/m² or higher between January 1, 2005, and December 31, 2022. Participants were divided into two groups based on whether they had undergone bariatric surgery.
To improve comparability between the groups, the researchers used propensity score matching based on factors including age, sex, race, ethnicity, BMI, hypertension, type 2 diabetes, socioeconomic status, smoking, alcohol use, and a history of neurological conditions. Following matching, each group comprised 32,552 individuals. The median follow-up period was 4.7 years for those who underwent surgery and 5.9 years for those who did not.
The analysis revealed the following findings:
  • Dementia: Individuals who underwent bariatric surgery had a 52% lower incidence of dementia than those who did not undergo the procedure (hazard ratio [HR] 0.48).
  • Parkinson’s disease: The surgical group had a 30% lower incidence of Parkinson’s disease (HR 0.70).
  • Cardiovascular disease: Bariatric surgery was associated with a 47% lower incidence of cardiovascular disease (HR 0.53).
  • Obesity-associated cancers: The incidence was 34% lower among individuals who underwent surgery (HR 0.66).
  • All-cause mortality: The surgical group had a 54% lower risk of death from any cause (HR 0.46).
  • The estimated 20-year survival probability was 84.7% in the bariatric surgery group, compared with 81.8% among individuals who did not undergo surgery.
The study’s observational design prevents causal conclusions, and the findings may be influenced by differences in healthcare access, patient selection, and unmeasured factors such as education and insurance coverage. The small number of Parkinson’s disease cases may also limit the reliability of this association.
The researchers concluded that bariatric surgery was associated with lower incidences of dementia and Parkinson’s disease, in addition to reduced cardiovascular disease, obesity-associated cancers, and mortality. Further studies are needed to confirm these findings and establish whether surgery directly reduces neurodegenerative disease risk.
Reference:
Shiekh, S. I., Papamargaritis, D., Goldney, J., Hernandes, G., Davies, M. J., Khunti, K., Yates, T., & Zaccardi, F. (2026). Bariatric surgery and risk of dementia and Parkinson’s disease in patients with obesity. International Journal of Obesity, 1-7. https://doi.org/10.1038/s41366-026-02222-z


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Article Source : International Journal of Obesity

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Medha Baranwal

Medha Baranwal holds a Bachelor’s degree in Biomedical Sciences from the University of Delhi and a Master’s degree in Biotechnology from Amity University. Since May 2018, she has been contributing to Medical Dialogues, writing and editing medical news articles that translate complex research into clear, accessible information for healthcare professionals.

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