title: Prevalence of Helicobacter pylori infection by birth year and geographic area in Japan.
abstract: BACKGROUND
  Helicobacter pylori (H. pylori)-related diseases are responsible for a tremendous amount of morbidity and mortality in Japan. We estimated the prevalence of H. pylori infection by sex, birth year, and geographic area among Japanese adults.
  
  
  METHODS
  This cross-sectional study included 14,716 subjects aged 20 years or more who underwent a health checkup between May 1997 and March 2013 in seven geographic areas throughout Japan. Relevant information on the demographics and status of H. pylori infection was retrieved from the electronic database. The univariate log-binominal regression model was used to estimate the prevalence of H. pylori infection, taking birth year into consideration. The multivariate log-binominal regression model was used to compare the prevalence of H. pylori infection between seven geographic areas.
  
  
  RESULTS
  The overall prevalence of H. pylori infection was 37.6% in women and 43.2% in men. Among seven geographic areas, Hokkaido showed the lowest prevalence (29.4%), while Yamagata Prefecture represented the highest (54.5%). The prevalence of H. pylori infection was highest in the 1940-1949 birth cohort and then decreased in the ensuing birth cohorts; the risk ratio (RR) was 0.85 (95% confidence interval (CI) 0.84-0.87) for changes in the 10-year birth cohort. Individuals in Yamagata Prefecture had the highest RR of acquiring H. pylori infection in all three birth cohorts (RR = 1.53 for 1940, RR = 1.69 for 1950, and RR = 1.85 for 1960) when compared with those in Hokkaido.
  
  
  CONCLUSIONS
  The prevalence of H. pylori infection increases with age and exhibits geographic variation in Japan. There has been a striking decrease in the prevalence of H. pylori infection, especially in younger Japanese populations.
authors: Department of Public Health, Aichi Medical University School of Medicine, Aichi, Japan.
authors: Junko
authors: J
authors: Ueda
authors: Masahiko
authors: M
authors: Gosho
authors: Yoshikatsu
authors: Y
authors: Inui
authors: Toru
authors: T
authors: Matsuda
authors: Masatoshi
authors: M
authors: Sakakibara
authors: Katsuhiro
authors: K
authors: Mabe
authors: Shigemi
authors: S
authors: Nakajima
authors: Tadashi
authors: T
authors: Shimoyama
authors: Mitsugi
authors: M
authors: Yasuda
authors: Takashi
authors: T
authors: Kawai
authors: Kazunari
authors: K
authors: Murakami
authors: Tomoari
authors: T
authors: Kamada
authors: Motowo
authors: M
authors: Mizuno
authors: Shogo
authors: S
authors: Kikuchi
authors: Yingsong
authors: Y
authors: Lin
authors: Mototsugu
authors: M
authors: Kato
mesh_terms: D000367:Age Factors; D000375:Aging; D000907:Antibodies, Bacterial / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D014644:Genetic Variation; D005843:Geography; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000453:epidemiology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D013274:Stomach Neoplasms / Q000453:epidemiology
chemical_list: D000907:Antibodies, Bacterial
keywords: H. pylori; birth cohort; gastric cancer; prevalence