Impact of Infectious Burden on Extent and Long-Term Prognosis of Atherosclerosis

Background — Recent findings suggest a causative role of infections in the pathogenesis of atherosclerosis. In hypothesizing an association between infectious agents and the development of atherosclerosis, we would expect a correlation to the extent of atherosclerosis. Moreover, this effect could be multiplied by the number of pathogens to which an individual had been exposed. Methods and Results — In 572 patients, IgG or IgA antibodies to herpes simplex virus 1 and 2, cytomegalovirus, Epstein-Barr virus, Hemophilus influenzae , Chlamydia pneumoniae , Mycoplasma pneumoniae , and Helicobacter pylori were measured. The extent of atherosclerosis was determined by coronary angiography, carotid duplex sonography, and evaluation of the ankle-arm index. Elevated IgA antibodies against C pneumoniae ( P <0.04) and IgG antibodies against H pylori ( P <0.02), cytomegalovirus ( P <0.05), and herpes simplex virus 2 ( P <0.01) were associated with advanced atherosclerosis (≥2 vascular regions), adjusted for age, sex, cardiovascular risk factors, and highly sensitive C-reactive protein. Infectious burden divided into 0 to 3, 4 to 5, and 6 to 8 seropositivities was significantly associated with advanced atherosclerosis, with an odds ratio (95% CI) of 1.8 (1.2 to 2.6) for 4 to 5 ( P <0.01) and 2.5 (1.2 to 5.1) for 6 to 8 seropositivities ( P <0.02) (adjusted). After a mean follow-up of 3.2 years, cardiovascular mortality rate was 7.0% in patients with advanced atherosclerosis and seropositive for 0 to 3 pathogens compared with 20.0% in those seropositive for 6 to 8 pathogens. Conclusions — Our results support the hypothesis that infectious agents are involved in the development of atherosclerosis. We showed a significant association between infectious burden and the extent of atherosclerosis. Moreover, the risk for future death was increased by the number of infectious pathogens, especially in patients with advanced atherosclerosis.