Chronic infection of Helicobacter pylori (H. pylori) in ischemic stroke (IS) 
incidence has been previously studied in several publications; however, 
conflicting results have been reported. A meta-analysis was used to assess 
whether chronic infection of H. pylori was associated with risk of IS, and which 
of the following was more effective for predication of IS risk, antibody IgG of 
H. pylori (anti-H. pylori IgG), antibody IgG of cytotoxin-associated gene-A 
(anti-Cag A IgG) or the (13)C-urea breath test. We searched the databases of 
Medline and Embase, and latest update was January 1, 2012. Case-control studies 
were considered to be eligible. The odds ratio (OR) and 95 % confidence interval 
(95 % CI) were calculated using the random-effect model. A total of 13 studies 
including 4,041 participants were included in this meta-analysis. Of these 
studies, ten, four and four studies were for anti-H. pylori IgG, anti-Cag A IgG 
and the (13)C-urea breath test, respectively. Combined analysis indicated that 
positive anti-H. pylori IgG, anti-Cag A IgG and (13)C-urea breath test were 
significantly associated with increased risk of IS, respectively, and positive 
anti-Cag A IgG was more effective for predication of IS risk [OR (95 % CI) = 
1.60 (1.21-2.11), P (heterogeneity) = 0.001 for positive versus negative anti-H. 
pylori IgG; 2.33 (1.76-3.09), P (heterogeneity) = 0.71 for positive versus 
negative anti-Cag A IgG and 1.65 (1.11-2.47), P (heterogeneity) = 0.17 for 
positive versus negative (13)C-urea breath test]. In addition, we found that 
positive anti-H. pylori IgG was closely associated with risk of IS caused by 
atherosclerosis and small artery disease, but not for cardioembolic IS. This 
meta-analysis indicated that chronic H. pylori infection was significantly 
associated with an increased risk of IS, especially for non-cardioembolic IS. 
Compared with anti-H. pylori IgG and the (13)C-urea breath test, anti-Cag A IgG 
seemed more effective for prediction of risk of IS.