Relationship between the birth cohort pattern of Helicobacter pylori infection and the epidemiology of duodenal ulcer.

BACKGROUND Helicobacter-pylori-related duodenal ulcer (DU) is an important cause of dyspepsia. AIM To determine the relationship between the pattern of H. pylori infection and the epidemiology of duodenal ulcer in a single population. DESIGN Prospective two-part study of (i) patients with DU referred for endoscopy because of dyspepsia, and (ii) the incidence of H. pylori infection in the general population of the same area. METHODS Details of 533 DU patients were recorded, and related to the pattern of H. pylori infection among 10 537 adults in the same community, determined by the (13)C-urea breath test. RESULTS In patients with DU, birth year was more important than age in determining the rate of presentation for endoscopy (the 'birth cohort' effect). H. pylori infection showed a similar birth cohort effect, and the prevalence decreased steadily in those born in successive years, from 28.8% in the 1930s to 3.5% in the 1970s. The proportion of dyspeptic patients who had duodenal ulcers also fell progressively, from 22.2% in 1979 to 5.7% in 1998. H. pylori prevalence and duodenal ulcer incidence were closely correlated at all ages. DISCUSSION Duodenal ulcer prevalence (as judged by the rate of referral of duodenal ulcer patients for endoscopy) is determined principally by the distribution of H. pylori infection in the local population. The birth cohort effect seen in adult duodenal ulcer patients reflects the acquisition of H. pylori in childhood. In Bristol, H. pylori prevalence and duodenal ulcer incidence are both declining to very low levels.