Abstract WP569: Gut Microbiota and Dementia: A Cross-Sectional Study

Abstract

Background: The gut microbiota is associated with several life-threatening conditions andthus might represent a useful strategy for the prevention of dementia. However, the association between gut microbiota and dementia has not yet been fully clarified. Hypothesis: There are differences in the components of gut microbiota between demented and non-demented patients. Methods: We recruited outpatients who visited our memory clinic to participate in this study. Information on patients’ demographics, risk factors, activities of daily living was collectedand cognitive function was assessed using neuropsychological tests and brain MRI scans. Faecal samples were obtained and the gut microbiota was assessed by terminal restriction fragment length polymorphism (T-RFLP) analysis, one of the most well-established and reliable 16S ribosomal RNA-based methods for classifying gut microbiota. Patients were divided into two groups, demented and non-demented. Multivariable logistic regression models were used to identify the variables independently associated with dementia. Results: We analyzed 128 eligible patients (female: 59%, mean age: 74.2 years). Silent lacunar infarcts and cerebral microbleeds were more frequently observed on MRI scans of patients with dementia. The T-RFLP analysis revealed differences in the components of gut microbiota: levels of Bacteroides (enterotype I) were decreased and other bacteria (enterotype III) were increased in demented compared with non-demented patients. Multivariable analyses showed that enterotype I (OR 0.1, 95%CI 0.02-0.4, P<0.001) and enterotype III (OR 12.7, 95%CI 3.3-65.8, P<0.001) were strongly associated with dementia, independent of the traditional dementia biomarkers. Faecal concentrations of ammonia, indole, skatole, and phenol were higher in demented compared with non-demented patients. Conclusion: Gut microbiota is an independent and strong risk factor for dementia.