The inter-relationship between Helicobacter pylori infection, dementia and mortality in type 2 diabetes: The Fremantle Diabetes Study Phase I

Background: Given sparse relevant data, the aim of this study was to determine whether Helicobacter pylori infection, including cytotoxin-associated gene-A (CagA) producing strains, is associated with dementia in type 2 diabetes (T2DM). Methods: Longitudinal data from 1115 participants in the community-based Fremantle Diabetes Study Phase I (mean age 64.0 years, 48.0 % males; 38.0 % H. pylori seronegative, 24.3 % H. pylori seropositive/CagA seronegative, and 37.7 % H. pylori/CagA seropositive at baseline) were analyzed. Results: During up to 19 years of follow-up, 50.3 % and 83.5 % of participants without and with incident dementia, respectively, died. In Cox proportional hazards models, H. pylori/CagA seropositivity (hazard ratio (95 % CI) 1.68 (1.15, 2.46), P = 0.008), but not H. pylori seropositivity/CagA seronegativity (P = 0.541) was an independent predictor of incident dementia, but neither H. pylori seropositivity/CagA seronegativity nor H. pylori/CagA seropositivity were significant predictors in competing risks models (P ≥ 0.280). Conclusions: Although CagA seropositivity in T2DM may have a contributory etiologic role in the risk of dementia, this may be through its association with reduced cardiovascular/all-cause mortality.