Abstract
BACKGROUND: The association between cognitive decline and Helicobacter pylori (H. pylori) infection remains controversial, with some evidence suggesting that H. pylori eradication may slow the progression of the disease. This meta-analysis aims to investigate the bidirectional relationship between H. pylori and cognitive decline. METHODS: We searched PubMed, Web of Science, the Cochrane Library, and Scopus for double-arm studies that reported either the prevalence of cognitive decline in individuals with H. pylori-positive status or the prevalence of H. pylori infection in patients with cognitive decline. A random-effects meta-analysis was conducted using Comprehensive Meta-Analysis software to pool the odds ratios from the included studies. Study quality was assessed using the Newcastle-Ottawa Scale. RESULTS: Our search identified 1,240 records, with 16 studies meeting the inclusion criteria. Meta-analysis showed that patients with H. pylori had a significantly higher risk of cognitive decline (OR = 1.338, 95% CI 1.046-1.713), with the strongest association seen in studies grouping cognitive dysfunction and dementia (OR: 3.190, 95% CI 1.853-5.490). However, the risk of Alzheimer's disease was insignificant. Cognitive decline cohorts showed a significantly higher prevalence of H. pylori (OR = 1.5, 95% CI 1.131-1.989), with a significant association with Alzheimer's disease (OR: 1.630, 95% CI 1.064-2.497), but not with dementia or cognitive dysfunction. The association varied across study designs, with cross-sectional studies showing no association in both analyses. Heterogeneity was substantial (I(2) > 70% in most analyses), highlighting variability in the findings. CONCLUSION: This meta-analysis indicates a bidirectional association between H. pylori and cognitive decline. While H. pylori infection increased the overall risk of cognitive decline, no significant link was found with Alzheimer's disease. Conversely, Alzheimer's disease patients had a higher prevalence of H. pylori infection. High heterogeneity underscores the need for further well-designed studies to clarify this relationship.