Association between infection with Helicobacter pylori and Chlamydia pneumoniae and risk of ischemic stroke subtypes - Results from a population-based case-control study

Background and Purpose-Helicobacter pylori and Chlamydia pneumoniae have be en associated epidemiologically and pathogenetically with coronary atherosc lerosis. However, population-based data on chronic infection and stroke are lacking. Therefore, we investigated the association of both bacterial path ogens and ischemic stroke subtypes in a population-based case-control study . Methods-Patients with first ischemic stroke in the population-based Erlange n Stroke Project were collected as cases. Neighborhood controls were drawn from the study population, matched for age, sex, and place of residence. Ig G antibodies to H pylori were measured by enzyme immunoassay, and IgG antib odies to C pneumoniae were measured by microimmunofluorescence technique. C onditional logistic regression was used. Analyses were stratified for etiol ogic stroke subtypes according to Trial of Org 10172 in Acute Stroke Treatm ent (TOAST) criteria. Results-A total of 145 case and 260 control subjects were included. Chronic H pylori infection was associated with a higher risk of stroke caused by s mall-artery occlusion (adjusted odds ratio, 3.31; 95% CI, 1.15 to 9.56) and a lower risk of cardioembolic stroke (adjusted odds ratio, 0.21; 95% Cl, 0 .06 to 0.71). Overall, elevated H pylori as well as elevated C pneumoniae a ntibodies were not associated with ischemic stroke. Conclusions-Our population-based study does not provide evidence of any str ong association between the immune response to C pneumoniae as a marker of prior infection and ischemic stroke. Further studies are required to reveal the role of chronic H pylori infection as an independent risk factor for t he subgroup small-artery occlusion.