title: Virulent strains of Helicobacter pylori and vascular diseases: a meta-analysis.
abstract: BACKGROUND
  Cytotoxin-associated gene A (CagA)-positive strains of Helicobacter pylori are an etiological factor for peptic ulcer and gastric cancer. Studies on the role of these virulent strains in vascular diseases yield conflicting results.
  
  
  METHODS
  We searched the MEDLINE database for relevant studies. Meta-analysis was performed using the random effects method.
  
  
  RESULTS
  We found 10 retrospective case-control studies (with 1527 case patients and 1661 control subjects) and 3 prospective cohort studies (with 701 case patients and 1439 control subjects) on CagA status and ischemic heart disease and 4 retrospective case-control studies (with 513 case patients and 590 control subjects) on CagA status and cerebral ischemia. In the case-control studies, an association of ischemic heart disease with CagA-positive strains (OR 1.87, 95% CI 1.46-2.40) but no significant association with CagA-negative strains (OR 1.15, 95% CI 0.83-1.60) has been found; in the 3 prospective studies, association with ischemic heart disease was weaker but still significant (OR 1.26, 95% CI 1.05-1.51). In the 4 case-control studies, CagA-positive strains were significantly associated with cerebral ischemia (OR 2.43, 95% CI 1.89-3.13), again with no association for CagA-negative strains.
  
  
  CONCLUSIONS
  We found a small but significant association between vascular diseases and virulent CagA-positive strains of H. pylori. The lack of association with CagA-negative strains further supports the hypothesis of an independent relationship between virulent strains of H. pylori and vascular diseases. The magnitude of the association with cerebral ischemia needs to be confirmed by prospective studies.
authors.affiliation: Cardiology Department, San Filippo Neri Hospital, Rome. vpasceri@hotmail.com
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Pasceri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Patti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cammarota
authors.forename: Christian
authors.initials: C
authors.lastname: Pristipino
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Richichi
authors.forename: Germano
authors.initials: G
authors.lastname: Di Sciascio
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D002561:Cerebrovascular Disorders / Q000821:virology*; D003327:Coronary Disease / Q000821:virology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000472:pathogenicity*; D006801:Humans
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori