Enterovirus infections as a possible risk factor for myocardial infarction

BACKGROUND: An increasing body of evidence suggests that, in addition to the well-known classic risk factors, some microbial infections may be associated with the development of atherosclerosis and myocardial infarction (MI). The aim of our study was to evaluate the possible role of enteroviral infections in the pathogenesis of MI. METHODS AND RESULTS: Stored sera, collected in Eastern Finland in 1977, from a set of 12 155 randomly selected men and women aged 25 to 64 years were used in prospective, nested case-control study. The study sample comprised 183 men and 81 women with MI and matched controls. The sera were tested for IgG antibodies to a newly identified enterovirus-common (EVC) antigen, to heat-denatured coxsackievirus B5 (CBV-5), and to adenovirus hexon protein. Raw data from enzyme immunoassays were converted to relative units before analysis. In univariate analysis, EVC antibodies were significantly associated with the risk of MI in men (P=0.009) but not in women. Men with MI had a significantly higher mean level of EVC antibodies than matched controls (P=0.014). High antibody levels to EVC were associated with an increased risk of MI in men aged 25 to 49 years (relative risk [RR] 4.34, P<0.001) but not in older men (>50 years of age). Women with MI also showed a trend toward higher antibody levels than control women, but the difference was not statistically significant. Antibody levels to whole CBV-5 or adenovirus hexon protein appeared to be no different among case patients versus control subjects. CONCLUSIONS: If we assume that a high level of EVC antibodies reflects a history of relatively frequent enterovirus infections, the present observation might suggest that enterovirus infections increase the risk of MI at least in middle-aged men. Further studies are needed to understand possible clinical significance of this observation.