Infection with virulent strains of Helicobacter pylori is not associated with ischaemic heart disease: evidence from a population-based case-control study of myocardial infarction

Background: Although the majority of evidence does not support association between Helicobacter pylori infection and ischaemic heart disease. the natu re of this relationship may differ when Virulence of the infecting strains are examined. Methods and results: The prevalence of IgG antibody evidence of infection with CagA positive stains of H. pylori was investigated in sto red plasma samples from 259 cases of myocardial infarction (aged 25-70 year s, 74 males) and 259 population based controls from the same area in Northe rn Ireland. Two-hundred and seventy (52.1%) subjects were seropositive for anti-CagA IgG. CagA seropositivity was more common in cases than in control s: 56.4 vs 47.9%, odds ratio for seropositivity in cases (95% CI) 1.41 (1.0 0, 1.99). Substantial attenuation of this relationship occurred on adjustme nt for age, sex, number of siblings, smoking and measures of socio-economic status: odds ratio (95% CI) 1.16 (0.79, 1.70). A similar pattern was seen for seropositivity for all H. pylori strains. Conclusion: Infection with th e more virulent strains of H. pylori, as with all strains, is not associate d with myocardial infarction. (C) 2000 Elsevier Science Ireland Ltd. All ri ghts reserved.