Enteroviruses and myocardial infarction.

Abstract:  BACKGROUND: Several lines of evidence suggest that some microbial infections are involved in the pathogenesis of atherosclerosis. The aim of the studies referred to here was to evaluate the possible role of enteroviral infections as potential risk factors for cardiac events. METHODS AND RESULTS: The association of enterovirus-specific antibodies and cardiac events was analyzed in 3 large, prospective population studies with the nested case-control design. Stored sera collected at the study baseline were tested for enterovirus group-specific immunoglobulin G antibodies. The study samples from the North Karelia Project, the Helsinki Heart Study, and the Mobile Clinic Health Service were composed of 183, 241, and 276 men with myocardial infarction, respectively, and their matched control patients. In 2 of the 3 studies, male cases without evidence of heart disease at the baseline had significantly higher levels of antibodies to enteroviruses than their matched control patients. High enterovirus antibody level was found to be a definite independent risk factor for future cardiac events. In the North Karelia study the risk was high in men aged 25 to 49 years, whereas in the Mobile Clinic Health Service study the risk was particularly strong in those with low levels of serum cholesterol. No association with high levels of enterovirus antibodies and cardiac events was seen in the Helsinki Heart Study, which consisted of hypercholesteremic men. CONCLUSIONS: If a high level of enterovirus group-specific antibodies can be considered as a sign of frequent enterovirus infections in the past, these studies suggest that enterovirus infections increase the risk of myocardial infarction at least in normocholesteremic men.