[Seasonal incidence of duodenal ulcer--a myth?].

A retrospective study was performed on 1091 acute duodenal ulcers found by endoscopy from 1973-1983. The chi 2-test verified statistically a maximum of ulcers in autumn. The vectorial analysis by means of the Rayleigh-Test showed a maximum of observed ulcers in November for all of the patients as well as for subjects with a duodenal ulcer seen only once, or with one relapse found endoscopically. Patients with three or more successive duodenal ulcers showed an individual pattern with or without seasonal periodicity. In chronic duodenal ulcer disease the individual long-time follow-up might be useful in prophylactic anti-ulcer therapy.