title: High prevalence of potentially virulent strains of Helicobacter pylori in the general male British population.
abstract: BACKGROUND
  Strains of Helicobacter pylori that express the cytotoxin associated gene product A (CagA) may be more strongly associated with serious gastric diseases, such as gastric cancer and peptic ulceration, than other strains. Data, however, are sparse on the prevalence, risk factors, and other correlates of these strains in the general population.
  
  
  OBJECTIVE
  To characterise aspects of the seroepidemiology of CagA(+) strains of H pylori in the general British population.
  
  
  METHODS
  We measured serum IgG antibodies to mixed H pylori antigens and separately to CagA in 1025 men aged 40-59 years who were randomly selected from a larger group of participants in a community based survey conducted in 18 different British towns.
  
  
  RESULTS
  Overall, 44% (95% confidence interval 41-47%) of the men were seropositive to CagA antibodies, representing about 61% (57-65%) of the men seropositive to mixed antigen H pylori. The risk factors for seropositivity to CagA antibodies were similar to those for seropositivity to mixed antigen H pylori, apart from an increased prevalence of reported bedroom sharing in childhood (p<0.01).
  
  
  CONCLUSIONS
  In a nationwide study of potentially virulent H pylori strains, there was a high prevalence of the infection, with some evidence that acquisition of such strains might occur earlier in life than other strains.
authors.affiliation: Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Radcliffe Infirmary, Oxford OX2 6HE, UK.
authors.forename: J
authors.initials: J
authors.lastname: Danesh
authors.forename: P
authors.initials: P
authors.lastname: Whincup
authors.forename: M
authors.initials: M
authors.lastname: Walker
authors.forename: L
authors.initials: L
authors.lastname: Lennon
authors.forename: A
authors.initials: A
authors.lastname: Thomson
authors.forename: P
authors.initials: P
authors.lastname: Appleby
authors.forename: C
authors.initials: C
authors.lastname: Hawkey
authors.forename: J C
authors.initials: JC
authors.lastname: Atherton
mesh_terms: D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology; D014774:Virulence
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; C080866:cagA protein, Helicobacter pylori