title: Helicobacter pylori (H pylori) infection in Greece: the changing prevalence during a ten-year period and its antigenic profile.
abstract: BACKGROUND
  To evaluate changes in H pylori infection prevalence in Greece during a ten-year period, and to examine its antigenic profile.
  
  
  METHODS
  Three groups of patients were studied. Group O-87: Banked serum samples of 200 consecutive adult outpatients, from the Hepato-Gastroenterology clinic of a teaching hospital at Athens, collected in 1987. Group O-97: Serum samples of 201 similarly selected outpatients from the same Unit, collected in 1997. Group BD-97: Serum samples of 120 consecutive blood donors from the same hospital, collected in 1997. H pylori IgG antibody seroprevalence was studied by a quantitative ELISA. Antigenic profile was studied by western-blot IgG assay, in 62 IgG positive patients of O-97 and BD-97. Results were analyzed by conventional statistics and multivariate regression analysis.
  
  
  RESULTS
  The H pylori seroprevalence increased with age in the three tested groups. In O-97, seroprevalence did not differ from that, in BD-97. On the contrary, there was a significant decrease in seropositivity between O-87 and O-97 (59.5% vs 49.2%, p = 0.039). Multiple regression analysis showed that age over 35 years (OR:3.45, 95% CI:1.59-7.49, p = 0.002) and year of patients' selection - that is 1987 or 1997 - (OR:1.73, 95% CI:1.14-2.65 for 1987, p = 0.010), were independent risk factors of H pylori infection. The seroprevalence of CagA+ and VacA+ strains was 77.4% and 58.5%, respectively, and type I(CagA+/VacA+) strains were significantly more common than type II(CagA-/VacA-) strains (59.7% vs 22.6%, p < 0.001).
  
  
  CONCLUSIONS
  During a ten-year period, we found a significant decrease of H pylori infection in Greece and our data support the birth cohort phenomenon as an explanation for the age-dependent increase of H pylori infection. The prevalence of CagA and/or VacA positive strains is relatively high, in a country with low incidence of gastric cancer.
authors.affiliation: Gastroenterology Unit of Pathophysiology, Athens University School of Medicine, Laikon General Hospital, Athens, Greece. periklisapo@yahoo.com
authors.forename: Periklis
authors.initials: P
authors.lastname: Apostolopoulos
authors.forename: Irene
authors.initials: I
authors.lastname: Vafiadis-Zouboulis
authors.forename: Michael
authors.initials: M
authors.lastname: Tzivras
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kourtessas
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Katsilambros
authors.forename: Athanasios
authors.initials: A
authors.lastname: Archimandritis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology*; D015153:Blotting, Western; D006115:Greece / Q000453:epidemiology; D016481:Helicobacter Infections / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D012307:Risk Factors; D016036:Seroepidemiologic Studies
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G