Published online Feb 28, 2008. doi: 10.3748/wjg.14.1286
Revised: December 9, 2007
Published online: February 28, 2008
AIM: To study the relationship between the cytotoxin-associated gene-A (CagA) status of H pylori strains and cerebral infarction among European Caucasians and Chinese Han by conducting a meta-analysis.
METHODS: Ten case-control studies, with data on a total of 907 cases and 966 controls, were retrieved and considered; disqualified studies were excluded. The included studies were then tested for heterogeneity, and a meta-analysis was performed.
RESULTS: The combined data revealed CagA-bearing strains of H pylori which cause chronic infection are associated with an increased risk of cerebral infarction (OR = 2.66, 95% CI: 2.17-3.26), but no such relationship was found with CagA-negative strains (OR = 0.74, 95% CI: 0.49-1.10) in the overall population. We performed subgroup analyses, dividing the overall population into European Caucasians and Chinese Han subgroups, and analyzed the studies according to their subgroup classification. Through the subgroup analysis, an association between cerebral infarction and CagA-bearing strains was found in both subgroups (OR = 2.60, 95% CI: 1.93-3.49 in Chinese Han; OR = 2.71, 95% CI: 2.05-3.59 in European Caucasians), but no significant association was found between cerebral infarction and CagA-negative strains (OR = 0.81, 95% CI: 0.45-1.48 in Chinese Han; OR = 0.64, 95% CI: 0.37-1.09 in European Caucasians).
CONCLUSION: These results suggest CagA-bearing strains of H pylori are significantly associated with susceptibility to cerebral infarction in Chinese Han and European Caucasians, but that CagA-negative strains are not a definite predisposing factor in either subgroup. The magnitude of this association with cerebral infarction needs to be confirmed by prospective studies and combined studies of H pylori eradication.