Meta-analysisindependent cross-checkabstract checked I-SRC-121 standard review
How common H. pylori is worldwide
Global Prevalence of Helicobacter pylori Infection: Systematic Review and Meta-Analysis.
Overview
Hooi JKY et al.. Gastroenterology 2017 · PMID 28456631 · DOI 10.1053/j.gastro.2017.04.022
About 70% of people in Africa carry H. pylori, so most positive tests there are correct.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Estimate global prevalence
- How was the study done?
Meta-analysis
- How many people, animals or samples were studied?
184 studies
- What was actually found?
Highest in Africa
- How large was the observed effect?
70.1% Africa
- What do the results mean in everyday life?
Positive tests are usually right where infection is common
- What are the study's limitations?
Heterogeneous studies
- What does it say about Elawady's specific claim?
Contradicts 70% false positives
- Do the results apply to Germany and Europe?
Moderate
- What can explicitly not be concluded from this study?
Egypt-specific figure
Scientific in-depth review
1. Full reference
- Authors
- Hooi JKY et al.
- Journal
- Gastroenterology
- Year
- 2017
- Identifier
- PMID 28456631 DOI 10.1053/j.gastro.2017.04.022
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works record checked
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
NIDDK grant; no COI statement in record.
2. Research question
What is the global prevalence of H. pylori infection?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of prevalence studies
- Population
Populations in 62 countries
- Country
International
- Period
Studies 1970-2016
- Sample size
184 studies
- Inclusion and exclusion criteria
Prevalence studies
4. Methods and endpoints
- Exposure / intervention
not applicable
- Comparator
Regions/countries
- Endpoints
Prevalence
- Statistical methods
Random-effects pooling
5. Actual results
- Results
Africa had the highest pooled prevalence (70.1%; 95% CI 62.6-77.7), Oceania the lowest (24.4%); country estimates from 18.9% (Switzerland) to 87.7% (Nigeria); about 4.4 billion people infected in 2015.
- Absolute risks
not applicable
- Authors' conclusion
More than half the world's population is infected, with large regional variation.
6. Strengths
- Large global synthesis
7. Weaknesses
- Heterogeneous methods; Egypt-specific estimate not in abstract
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Heterogeneity.
9. Assessment of the statistical interpretation
High prevalence raises positive predictive value of any test (see stats/C-SRC-50_ppv_hpylori.py).
10. Relevance to the specific claim
In high-prevalence regions such as Africa (70.1%), most positive tests are true positives, which contradicts '700 of 1000 positives are false'.
11. Independent contrary findings
12. Transferability to Germany and Europe
Prevalence lower in Europe; PPV lower there.
13. Overall methodological judgement
Context for predictive values.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | indirect |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- The common test for H. pylori ('the stomach germ') is the test with the highest rate of false-positive results. – Studies contradicting or limiting the claim