title: No increase in gastric acid secretion in healthy Japanese over the past two decades.
abstract: BACKGROUND
  The prevalence of gastroesophageal reflux disease (GERD) has been increasing worldwide over recent decades. A previous study demonstrated that gastric acid secretion, thought to be an important factor in the increase in the rate of GERD, in Japanese individuals increased in the era from the 1970s to the 1990s. The aim of this study was to evaluate whether gastric acid secretion has altered over the past two decades with and without the influence of Helicobacter pylori infection in nonelderly and elderly Japanese.
  
  
  METHODS
  Gastric acid secretion, the concentrations of serum gastrin, pepsinogen I, and pepsinogen II, and H. pylori infection were determined in 78 healthy Japanese subjects. The findings were compared with data obtained in the 1990s.
  
  
  RESULTS
  Basal acid output (BAO) and maximal acid output (MAO) gradually decreased with age in H. pylori-negative subjects. In addition, those with H. pylori infection tended to show decreased gastric acid secretion as compared with those without infection, particularly in the elderly group. MAO decreased gradually with age in males, whereas it remained unchanged with age in females. MAO in H. pylori-negative subjects has not changed over the past two decades (17.7 mEq/h vs 17.6 mEq/h in nonelderly subjects, and 15.2 mEq/h vs 12.7 mEq/h in elderly subjects).
  
  
  CONCLUSIONS
  In contrast to the increased prevalence of GERD, gastric acid secretion has not increased over the past two decades in Japanese. However, secretion has decreased with age in males but not in females, which may partly explain the sex difference in the age-related GERD prevalence.
authors.affiliation: Department of Gastroenterology and Hepatology, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan, ishimura@med.shimane-u.ac.jp.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Ishimura
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Owada
authors.forename: Masahito
authors.initials: M
authors.lastname: Aimi
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Oshima
authors.forename: Tomoari
authors.initials: T
authors.lastname: Kamada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Inoue
authors.forename: Hironobu
authors.initials: H
authors.lastname: Mikami
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Hiroto
authors.initials: H
authors.lastname: Miwa
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Higuchi
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kinoshita
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism; D015992:Body Mass Index; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005755:Gastrins / Q000097:blood; D016481:Helicobacter Infections / Q000097:blood*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020116:Pepsinogen A / Q000097:blood; D020115:Pepsinogen C / Q000097:blood; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D005755:Gastrins; D020115:Pepsinogen C; D020116:Pepsinogen A