Influenza virus infection and risk of acute myocardial infarction.

Increasing evidences have shown that pathogens might promote atherosclerosis and trigger acute myocardial infarction (AMI). But the conclusions from various studies on the correlation between previous influenza virus (IV) infection and AMI were inconsistent. We conducted a case-control study to assess the association of previous IV infection and AMI. Questionnaire survey was conducted to collect information about demographic characteristics and heart disease risk factors. Fasting blood sample was obtained to measure IgG antibodies to influenza virus A(IV-A), influenza virus B(IV-B), cytomegalovirus (CMV), herpes simplex virus type-1 (HSV-1) and type-2 (HSV-2), adenovirus (ADV), rubella virus (RV) and Chlamydia pneumoniae (CP) and measure the level of some biochemistry markers. Compared to controls, cases were more likely to have positive IgG antibodies to IV-A and IV-B (IV-A: OR, 3.3; 95%CI, 1.5 to 7.4; IV-B: OR, 17.2; 95%CI, 7.7 to 38.0). After adjustment for potential confounding variables, the risk of AMI was still associated with the presence of IgG antibodies to IV-A (adjusted OR, 7.5; 95%CI, 1.3 to 43.0) and IV-B (adjusted OR, 27.3; 95%CI, 6.6 to 113.8). The study supported the hypothesis that previous IV infection took part in the development of atherosclerosis and trigger the occurrence of AMI.