Effect of age on the frequency of active Campylobacter pylori infection diagnosed by the [13C]urea breath test in normal subjects and patients with peptic ulcer disease.

We studied the frequency of active Campylobacter pylori infection in persons from North America (n = 53) or the People's Republic of China (n = 15) who had no gastrointestinal symptoms or a history of ulcer disease and in patients with active or recently active duodenal or gastric ulcers diagnosed by endoscopy (n = 105). C. pylori infection was significantly (P less than .001) more frequent in patients with peptic ulcers (88%) than in the normal group (45%). An age-related increase in the frequency of C. pylori infection in subjects with no gastrointestinal symptoms paralleled the known age-related increase in prevalence of gastritis. The frequency of C. pylori infection in patients with duodenal ulcers was greater than 80%, irrespective of age. C. pylori infection was more common in the Chinese group (age, 20-39 y) than in the North American group of the same age (60% vs. 24%). Association of C. pylori with specific diseases should not be inferred without knowing the prevalence of C. pylori infection in reference populations of the same age and ethnic background.