Seroprevalence of Helicobacter pylori and incident myocardial infarction - A population-based Swedish nested case-control study

Aims: Helicobacter pylori (H. pylori) and its cytotoxin-associated gene A (CagA) have been associated with myocardial infarction (MI), but existing data are conflicting possibly due to limitations in study designs and lack of data on important confounders. The aim of this study was to determine whether H. pylori or CagA seropositivity is associated with incident MI, including MI phenotypes, and to describe temporal trends.

Methods: We used the Northern Sweden Health and Disease study, a prospective biobank with data from residents enrolled in a population-based cohort from health examinations between 1986 and 2006. A total of 826 first time MI cases with available blood samples from their index health examination were identified up to 2006. Each case was 1:2 matched with controls by age, sex, sample date and geographical area. Blood samples were analysed using ELISA to determine seroprevalence of H. pylori and CagA, which were then used to study the association with incident MI.

Results: The median age at baseline was 50 years, and 71% of participants were male. Seroprevalence of H. pylori and CagA was 46.5% and 32.1% in cases, respectively, compared to 43.7% and 30.6% in controls. Overall, H. pylori prevalence decreased over the study period. After multivariable adjustments, no significant association was observed between H. pylori seropositivity and incident MI (odds ratio: 1.15, 95% CI 0.94-1.42) nor between CagA-positive H. pylori and incident MI.

Conclusion: In a Swedish population-based cohort, no significant association was observed between H. pylori or CagA seropositivity and incidence of MI.