Infection, atherosclerosis and ischemic stroke

The established risk factors for ischemic stroke no nor sufficiently explain all clinical and epidemiological features of the disease, such as the winter peak of stroke incidence, the decline of stroke during this century and the time point of cerebral ischemia. A role of infectious disease as stroke risk factor may partly explain above features. Several case-control studies with both hospital and population control groups showed that acute infection within the preceding week and mainly respiratory infection of both viral and bacterial origin increase the risk of cerebral ischemia independent from other risk factors (odds ratio 2.9-14.5). Infection as a risk factor appears to be most important in young age groups. Infection may cause a procoagulant state and thus, trigger thrombosis and cerebral ischemia. There is increasing evidence for chronic infection as stroke risk factor. A case-control study indicated chronic and recurrent bronchitis to increase stroke risk. Two case-control and one cohort study showed that chronic dental infection, mainly parodontitis, is a risk factor for stroke. There ape conflicting results on chronic infection with cytomega-lovirus and insufficient evidence for a role of Helicobacter pylorii infection in pathogenesis of stroke. Seroepidemiological studies and analyses of carotid plaques indicate a role of Chlamydia pneumoniae in ischemic stroke. However, causality can not yet be inferred from present results. Acute and chronic infectious diseases are treatable and partly preventable conditions. Their recognition as stroke risk factors could therefore be important for stroke prevention.