Recurring Gastrointestinal Infections Increase the Risk of Dementia

BACKGROUND: Gastrointestinal infections cause significant health problems, including those affecting the immune, musculoskeletal, and nervous system, and are one of the leading causes for death worldwide. Recent findings suggest that microbiota of the gastrointestinal tract contribute to dementia. OBJECTIVE: In this nested case-control study we investigated the role of common gastrointestinal infections on the subsequent risk of dementia. METHODS: We used a longitudinal sample of 202,806 individuals from health claims data of the largest German health insurer and applied a nested case-control design with 23,354 initial dementia cases between 2006 and 2014 and 23,354 matched controls. We used conditional logistic regression to compute odds ratios (ORs) for dementia and corresponding 95%confidence intervals (CIs), adjusting for potential confounders. RESULTS: The risk of dementia was increased in patients with recurring incidences of quarters with diagnosed gastrointestinal infections when compared to the unexposed population (one quarter: OR = 1.49, 95%CI = 1.40–1.58; two quarters: OR = 1.70, 95%CI = 1.51–1.91; three or more quarters: OR = 1.64, 95%CI = 1.40–1.93), adjusted for potential confounders. CONCLUSION: Our findings suggest that recurring gastrointestinal infections are associated with an increased risk of subsequent dementia.