Occurrence of a cohort phenomenon in peptic ulcer mortality from Switzerland.

The present study was undertaken to examine whether the cohort phenomenon of peptic ulcer mortality is unique to the British population or whether it is a common feature of peptic ulcer disease. The occurrence of a cohort phenomenon was also found in data on peptic ulcer mortality from Switzerland. Swiss birth-cohorts born around 1870 and 1900 had been exposed to a maximum risk of dying of gastric and duodenal ulcer, and they carried this risk throughout their lives. By the time lag between both ulcer types, a common early determinant precipitating both diseases is made unlikely. The British cohort phenomenon was thought to result from high-risk birth-cohorts suffering mostly from the early phase of urbanization, World War I, and world economic crisis. This explanation, however, does not pertain to the high-risk cohorts from Switzerland. The nature of the determinants of peptic ulcer that occur early in the life of a cohort remains unknown.