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Review
. 2025 Sep 16;30(1):846.
doi: 10.1186/s40001-025-03160-8.

The association between H. pylori infection and cognitive deterioration: a systematic review and meta-analysis

Mahmoud M Elhady  1 , Abdelrahman Zidan  2 , Eslam Mohammed Rabea  3 , Heidi Sherif Farouk  3 , Moustafa Z Elattar  4 , Manar Adel  5 , Mariam Abdulkhaliq Khalil  3 , Amira A Aboali  3   6 , Marwa Abdel Aziz Zeid  7 , Mohamed A Shaltout  8   9 , Alzahraa M Abdel-Daim  10 , Asmaa Gomaa Alwarraqi  3 , Hazem AbuEl-Enien  11 , Mohamed Sayed Zaazouee  8
Affiliations
Review

The association between H. pylori infection and cognitive deterioration: a systematic review and meta-analysis

Mahmoud M Elhady et al. Eur J Med Res. .

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 (I2 > 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.

Keywords: Association; Cognitive decline; Dementia; H. pylori; Infection; Meta-analysis.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Prisma flowchart
Fig. 2
Fig. 2
Forest plot illustrating the pooled association between H. pylori infection and cognitive decline risk
Fig. 3
Fig. 3
Forest plot illustrating the pooled association between H. pylori infection and cognitive decline risk, stratified by disease definitions and by study designs
Fig. 4
Fig. 4
Funnel plot assessing publication bias in the meta-analysis of cognitive decline risk in patients with H. pylori infection
Fig. 5
Fig. 5
Forest plot illustrating the pooled association between risk of H. pylori infection and cognitive decline
Fig. 6
Fig. 6
Forest plot illustrating the pooled association between risk of H. pylori infection and cognitive decline, stratified by disease definitions and by study designs
Fig. 7
Fig. 7
Funnel plot assessing publication bias in the meta-analysis of H. pylori infection risk in patients with cognitive decline
See this image and copyright information in PMC

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