title: Study designs and diagnostic criteria need standardization to effectively compare worldwide ulcer trends.
abstract: The development of technology and worldwide communication systems has spurred the growth of international comparative studies. These comparative epidemiological studies can be fruitful if they utilize a uniform approach. We address some of the strengths and limitations of these types of studies, and suggest they should be carried out using prospectively designed protocols.
authors.forename: J H
authors.initials: JH
authors.lastname: Kurata
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D010437:Peptic Ulcer / Q000453:epidemiology*; D012107:Research Design