Background & aims: CagA-positive Helicobacter pylori infection has been more closely associated with gastric disease than CagA-negative infection. This study evaluated whether geographic variation in the prevalence of CagA could explain variation in gastric cancer rates.
Methods: The Eurogast study was conducted in 17 centers in 13 countries. Gastric cancer rates were calculated for each center, and serum samples from approximately 2850 subjects were assayed for immunoglobulin G antibodies to H. pylori and CagA and for pepsinogens A and C.
Results: The proportion of CagA-positive H. pylori infections varied across the centers, but this variation did not explain any more of the variation in gastric cancer rates than H. pylori alone. Subjects with CagA-positive infection had, however, significantly higher pepsinogen levels and a lower pepsinogen A/C ratio than subjects with CagA-negative infection; this pattern was observed consistently across the study centers.
Conclusions: Variation in the seroprevalence of CagA did not explain geographic variation in gastric cancer rates any better than H. pylori alone. However, the consistent variation in pepsinogen levels with CagA status across the study centers supports the importance of the role of CagA in the development of gastric disease.