Interaction between alimentary surgery and risk of dementia: a nationwide population-based case–control study.

Background Based on current research, it is known that the gastrointestinal tract microbiota and its genome play a crucial role in mental illnesses. Studies indicate a direct correlation between gastrointestinal tract microbiota and the onset of dementia, mediated by metabolic diseases and low-grade inflammation. The association between various gastrointestinal symptoms and neurodegenerative diseases has been recently discussed. However, there is a lack of research regarding the comparative effects of different surgical procedures on neurodegenerative diseases. Therefore, this study primarily focuses on comparing the association between various gastrointestinal surgeries and dementia, aiming to provide guidance for future clinical practice. Method A nationwide study using the Taiwanese National Health Insurance Research Database included 26 059 patients diagnosed with dementia or Alzheimer's disease and 104 236 controls without diseases. Primary exposures were defined as alimentary surgeries, encompassing cholecystectomy, gastrectomy, bowel resection, and appendectomy. Conditional logistic regression was used to examine the odds ratio and 95% confidence interval for prior alimentary surgery between cases and controls. Results The results showed that individuals with dementia had a higher rate of gastrectomy. Additionally, individuals with dementia seemed to exhibit a reduced rate of cholecystectomy and appendectomy. Regarding Alzheimer's disease, all four alimentary surgeries showed comparable trends to those observed with dementia. No significant interaction was observed between alimentary surgery and dementia among the four types of surgery evaluated. Conclusion Our study demonstrates that gastrectomy is associated with an elevated risk of dementia. We aim to uncover more direct evidence in future experiments. Key messages What is already known on this topic — In the past, numerous clinical and animal experiments have delved deep into the gut–brain axis. In these studies, some have focused on psychiatric disorders, while others have emphasized neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Based on the existing research, some investigations have approached the topic from the perspective of gastrointestinal diseases, others have extended their exploration into the realm of genetics, and some have scrutinized the composition of the gut microbiota in relation to dementia. It is evident that in certain patients with gastrointestinal diseases, alterations in the gut microbiota can potentially lead to the onset of dementia. What this study adds — Dementia and Alzheimer's disease have always been significant neurological disorders, impacting the autonomy of patients and posing a substantial societal burden. To the best of our knowledge, there are currently no dementia-related research papers associated with gastrointestinal surgery. However, gastrointestinal surgery has a profound impact on the gut microbiota, and it is a commonly performed procedure, thus holding significant implications for public health. Through this study, we can uncover the connection between gastrointestinal surgery and dementia, providing valuable insights for future research in prevention, treatment, and prognosis. How this study might affect research, practice, or policy — In this research, we offer further interventions following gastrointestinal surgery to prevent the onset of dementia. This can serve as a foundation for related animal and clinical studies, fundamentally alleviating the burden of dementia on patients, their families, and society as a whole. [ABSTRACT FROM AUTHOR]