Helicobacter pylori infection and mode of transmission in a population at high risk of stomach cancer

Background Helicobacter pylori (H. pylori) is a recognized cause of chronic gastritis and peptic ulcer disease, and is strongly suspected to play a role in the aetiology of stomach cancer but little is known about the mode of transmission. Aim To determine the prevalence of H. pylori infection in children and investigate potential modes of transmission in rural China. Subjects and setting We examined 98 children aged 3-12 years and 289 adults aged 35-64 years in a village in Linqu County, China, which has one of the highest rates of stomach cancer in the world. Method H. pylori infection was determined by C-13-urea breath test in children and by an enzyme-linked immunosorbent assay in adults. Results Among 98 tested children, 68 (69%) were H. pylori positive, but the prevalence rates varied as a function of age, rising from about 50% at ages 3-4 to 85% at ages 9-10 before falling to 67% at ages 11-12. Boys had a higher infection rate than girls (77.8% versus 59.1%, P <0.05). Among 289 adults, 195 (68%) were H. pylori positive, with a somewhat higher rate of positivity in younger compared to older age groups. The prevalence of H. pylori infection clustered within families. In families with at least one infected parent, 85% of children were H, pylori positive, while in families with both parents uninfected, only 22% of children were H. pylori positive (odds ratio [OR] = 30.4, 95% CI : 4.0-232). Conclusions These findings demonstrate the acquisition of H. pylori infection during early childhood in a population at high risk of stomach cancer, in a manner consistent with a person-to-person mode of transmission between parents and children.