<i>Helicobacter pylori</i> and Alzheimer's disease risk: The HUNT study

BackgroundInfections may contribute to Alzheimer's disease (AD) pathogenesis. Prior studies on the relationship between <i>Helicobacter pylori</i> (H. pylori) infection and AD or dementia have shown differing results.ObjectiveWe investigated whether H. pylori serology is associated with the risk of AD and dementia in the Trøndelag Health Study (HUNT).MethodsThe HUNT cohort study measured serum H. pylori antibody titers using the Pyloriset EIA-IgG test. 22 years after baseline serum sampling, cognitive assessments were conducted using standardized tests and proxy interviews. We performed logistic regression (n = 1364) adjusted for sex and age to estimate odds ratios for cognitive outcomes. Subgroup analyses were stratified by sex, age, Apolipoprotein E4 <i>(APOE</i> ε4) carrier status and high sensitivity serum C-reactive protein levels and sensitivity analyses further adjusted for lifestyle and co-morbidity risk factors. Cox regression models (n = 4689) were used to estimate hazard ratios for all-cause mortality.ResultsH. pylori titers were not associated with AD (OR 0.99 per 1 SD higher titer, 95% CI 0.82-1.20) or dementia (OR 0.98, 95% CI 0.84-1.15). There were no associations between H. pylori seropositivity (≥ 300 titers) and AD (OR 1.10, CI 0.75-1.63) or dementia (OR 0.96, CI 0.68-1.32). Stratifications by sex, age, CRP, or <i>APOE</i> ε4 genotype and adjusting for additional covariates showed no associations. All-cause mortality was higher with H. pylori positivity (HR 1.07, CI 1.03-1.11).ConclusionsH. pylori was not associated with later AD or dementia in this study. The relationship between specific versus multi-pathogenic infection burden and neurodegenerative diseases warrants further clarification.