Abraham Nomura, Grant N. Stemmermann, Po-Huang Chyou, Guillermo I. Perez-Perez, Martin J. Blaser

To determine whether a preexisting Helicobacter pylori infection increases the risk for developing duodenal or gastric ulcer. A nested case-control study based on a cohort of 5443 Japanese-American men who had a physical examination and a phlebotomy from 1967 to 1970. All 10 general hospitals on the Hawaiian island of Oahu. 150 patients with gastric ulcer and 65 patients with duodenal ulcer identified in the cohort of study participants after a hospital surveillance period of more than 20 years. Stored serum specimens from patients and from matched controls were tested for the presence of serum IgG antibody to H. pylori using enzyme-linked immunosorbent assay. 93% of the 150 patients with gastric ulcer and 78% of the matched controls had a positive antibody level for H. pylori-specific IgG, yielding an odds ratio of 3.2 (95% CI, 1.6 to 6.5). For duodenal ulcer, 92% of the 65 patients and 78% of the matched controls had a positive test result, yielding an odds ratio of 4.0 (CI, 1.1 to 14.2). As the level of antibody to H. pylori increased, a statistically significant increase was noted in the risk for gastric and duodenal ulcer. The association with H. pylori infection was statistically significant for both types of ulcer, even when the diagnosis was made 10 or more years after the serum sample had been obtained. Preexisting H. pylori infection increases the risk for subsequent development of either duodenal or gastric ulcer disease.