Does H. pylori infection cause gastric adenocarcinoma?
Many case-control and cohort studies have shown a relationship between H. pylori infection and gastric adenocarcinoma (2-4). A meta-analysis of 19 studies showed summary odds ratio for gastric cancer in H. pylori-infected patients is about 2 (4). The studies suggest that H. pylori-infected younger patients have a higher relative risk for gastric cancer than older patients with odds ratios of 9 at age 29 years but 1.05 at age 70 years. These studies indicated that H. pylori infection is equally associated with the intestinal or diffuse type of gastric cancer. Since many patients with gastric cancer may lose evidence of prior H. pylori infection and the studies did not consistently use the most sensitive methods of detecting H. pylori infection, the influence of H. pylori on gastric cancer was underestimated by these studies. A recent prospective study from Japan gave clearer data (5). They prospectively studied 1526 Japanese patients. 1246 had H. pylori infection and 280 did not. The me
