Association between infections with CagA-positive or -negative strains of Helicobacter pylori and risk for gastric cancer in young adults

OBJECTIVE: We assessed the association between infection with CagA-positive and -negative Helicobacter pylori and the risk of gastric cancer in young adults. METHODS: CagA IgG antibodies were measured in sera of subjects participatin g in a case-control study in Japan. The study subjects were 103 gastric can cer patients <40 yr of age, 100 inpatients with benign diseases, and 101 sc reenees younger than age 43 yr. RESULTS: Compared with the H. pylori-negative/CagA-negative (H. pylori-/Cag A-) group, both the H. pylori-positive/CagA-negative (H. pylori+/CagA-) gro up and the H. pylori-positive/CagA-positive (H. pylori+/CagA+) groups showe d elevated odds ratios for intestinal-type, diffuse-type, early, advanced, proximal, and distal gastric cancers. All the relationships were significan t except for the H. pylori+/CagA- group in relation to proximal cancer. The overall odds ratios (95% confidence intervals) for gastric cancer in the H . pylori+/CagA- and the H. pylori+/CagA+ groups were 15.0 (6.4, 35.2) and 1 4.6 (6.7, 31.9), respectively. Between these two groups, no significant dif ference was observed in risks for intestinal-type, diffuse: type, early, ad vanced, proximal, or distal gastric cancer. CONCLUSIONS: In those <40 yr of age, it is concluded that both CagA-positiv e and CagA-negative H. pylori infections are related to risks of intestinal -type, diffuse-type, early, advanced, and distal gastric cancers. (Am J Gas troenterol 1999;94:3455-3459. (C) 1999 by Am. Coll. of Gastroenterology).