Table 1

Studies on the number of Helicobacter pylori-infected individuals and prevalence rate of infection

First authorNo of subjectsPopulationStudy designObservation year
Asaka27 426Asymptomatic children, students and adults (participating at the health screening centre) living in Sapporo, HokkaidoObservational study1990
Fujisawa31 349Healthy persons living in seven prefectures in the central part of JapanObservational study1974
Watabe32 6 983Participants in a mass health appraisal programmeObservational study1996
Ueda33 14 716Individuals who underwent a health check-up in seven prefectures (Hokkaido, Aomori, Yamagata, Gunma, Aichi, Shiga and Kagawa)Observational study2005
Shiota34 5 550Patients of Oita University Hospital, Oita, JapanObservational study2009