Background: A number of epidemiological studies have reported on associations of coronary heart disease and raised levels of IgG serum antibodies to Helicobacter pylori. There is substantial uncertainty about the interpretation of these reports, however, as some authors have emphasised the most extreme findings to claim that a causal association exists, whereas others have reported the existence of no strong correlations.
Methods: A systematic review of the published literature was conducted.
Results: More than twenty relevant epidemiological reports were identified. There was a tendency towards larger odds ratios in smaller case-control studies that recruited controls opportunistically (e.g., hospital inpatients without heart disease) and that did not adjust for many confounders. Overall, the prospective studies reported no strong correlations between coronary heart disease and H. pylori infection. Even in a combined analysis, however, these studies were too small to be able to confirm or refute the existence of weak associations.
Conclusion: Residual confounding by causal risk factors may well account for the weak associations that have been reported between coronary heart disease and H. pylori.