Chlamydia pneumoniae and cytomegalovirus seropositivity, inflammatory markers, and the risk of myocardial infarction at a young age

Background Pathogens causing chronic infections may promote atherosclerosis. The aim of our study was to evaluate the association of Chlamydia pneumoniae (Cp) and cytomegalovirus (CMV) infection and of inflammatory activation with premature myocardial infarction (MI). Methods Specific anti-Cp and anti-CMV immunoglobulin G (IgG), fibrinogen, white blood cells (WBC), and C-reactive protein (CRP) were measured in 120 post-Ml patients less than or equal to 50 years old and in 120 age-matched controls. Results Seropositivity to Cp and elevated concentrations of anti-Cp and anti-CMV IgGs were more frequent (P = .01) in patients than in control subjects, and fibrinogen, CRP, and WBC levels (P = .02) were more elevated. After adjustment for coronary risk factors and socioeconomic status, the odds ratios (95% confidence intervals) for premature MI were 2.4 (1.3-4.6) for Cp infection and 2.9 (1.5-5.8) for CMV. The risk of Cp infection was greater in smokers (3.7, 1.8-7.6). When both infections were present (35% of patients vs 8% of controls, P = .001), CRP was higher (P = .01) and the risk increased by 12 times (12.5, 4-38.9) compared with that in subjects without any infection and by 5 times (4.9, 2.2-10.9) if only one was present. Conclusions After adjustment for confounders, seropositivity to both Cp and CMV infections is associated with the diagnosis of premature MI. The combination of both infections is associated with an enhanced inflammatory response and a markedly increased risk of premature MI.