The Study
Association between autoimmune thyroid disease and presence of CagA and gastric intestinal metaplasia among patients with H. pylori: a cross-sectional endoscopic study
This study looked at people who already had stomach tests and thyroid problems, and found that those with Graves' disease were more likely to have a certain type of stomach bacteria. But it doesn't prove the bacteria caused the disease — maybe the disease made it easier for that bacteria to stick around.
Analysis score
Maximum 58 for a case-control study.
Where the score came from
Some people with a stomach bacteria called H. pylori also get thyroid problems. This study looked at whether a more dangerous version of the bacteria (cagA-positive) is more common in people with Graves’ disease — an autoimmune condition that makes the thyroid overproduce hormones.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 558 / 100
Quality score
Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This suggests the bacteria might be helping trigger or worsen Graves’ disease in some people — especially if the thyroid is still intact and not destroyed by treatment.
- 2All 7 Graves’ patients in the study had the dangerous cagA version of H.
- 3pylori.
- 4Only 64% of people without thyroid disease had it.
- 5Hashimoto’s patients were less likely to have it (39%), but this wasn’t strong enough to be sure.
- 6After treating the bacteria, some Graves’ patients’ thyroid hormone levels dropped.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
BMC Endocrine Disorders
Year
2026
Authors
Angel Hailemariam, K. Han, Jacqueline Emerson, Bryan C Batch, Shannon J. McCall, Nina Salama, Frances Wang, Katherine S. Garman, M. Epplein
Related Content
Claims (6)
In this study, all individuals with Graves' disease were Black, and cagA-positive Helicobacter pylori was more common among Black people overall, suggesting that race may affect how this bacterial strain relates to Graves' disease.
In people with Graves' disease and a specific strain of H. pylori bacteria, removing the bacteria leads to lower levels of thyroid-stimulating hormone when no other thyroid treatment is given.
In people infected with Helicobacter pylori, those who have Graves' disease are more likely to carry bacterial strains with the cagA gene than those without Graves' disease.
In people infected with Helicobacter pylori, those diagnosed with Hashimoto’s thyroiditis have a lower rate of infection with cagA-positive bacterial strains compared to those without Hashimoto’s thyroiditis, though the difference is not statistically significant.
In people with a confirmed Helicobacter pylori infection, the presence of a precancerous stomach condition called gastric intestinal metaplasia occurs at the same rate regardless of whether the person has Graves' disease or Hashimoto's thyroiditis.
Infection with Helicobacter pylori leads to Graves' disease by triggering an immune response that mistakenly targets the thyroid gland due to structural similarities between bacterial and thyroid proteins.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.