title: Apparent incidence of Helicobacter pylori in adulthood: to what extent do new infections reflect misclassification?
abstract: BACKGROUND
  Helicobacter pylori infection is a key risk factor for a variety of gastrointestinal diseases. About half of the world population is infected. Most infections are acquired early in childhood, but the occurrence of new infections among adults has also been suggested.
  
  
  METHODS
  We review epidemiological studies providing estimates of incidence of H. pylori infection among adults and evaluate to what extent incidence estimates might have been affected by measurement error of infection status.
  
  
  RESULTS
  Thirty-two studies could be included in the review. Annual incidence was lower than 1.0 % in 17 studies; no correlation between length of follow-up and cumulative incidence was observed. Apparent cumulative incidences of the magnitudes observed in most studies would be expected, because of less than perfect sensitivity and specificity of the diagnostic tests, even in the absence of any true new infections. CONCLUSION/IMPACT: Apparent incidence rates of H. pylori infection among adults in Western populations should be interpreted with utmost caution.
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, D-69120 Heidelberg, Germany. m.weck@dkfz.de
authors.forename: Melanie N
authors.initials: MN
authors.lastname: Weck
authors.forename: Hermann
authors.initials: H
authors.lastname: Brenner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D055815:Young Adult