Chlamydia pneumoniae infection is not involved in carotid artery stenosis

Recent studies have suggested the existence of a close relationship between Chlamydia pneumoniae infection and atherosclerosis. However, it has been speculated that C. pneumoniae infection is not associated with early atherosclerosis but with advanced atherosclerosis. In the present study, we test this hypothesis. In 524 consecutive patients who underwent cerebral angiography were recruited for the study. From the films obtained during angiography, percent stenosis of neck internal carotid artery was calculated according to the method of the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Serum C. pneumoniae IgG and IgA antibodies were measured by a commercial ELISA enzyme immunoassay kit. Cerebrovascular risk factors such as age, gender, hypertension, diabetes mellitus, hyperlipidemis and smoking were assessed by interview. Old age above 60 years and diabetes mellitus were found to be independent risk factors for carotid artery stenosis in this study after adjustment for cerebrovascular risk factors. When we defined carotid artery stenosis as the presence of greater than 30% stenosis of one artery, there was no association after adjustment for other risk factors between C. pneumoniae IgG and IgA seropositivity and the presence of carotid artery stenosis for any cut-off value of seropositivity. When we defined carotid artery stenosis as the presence of greater than 70%, there was also no association between C. pneumoniae IgG and IgA seropositivity and the presence of carotid artery stenosis for any cut-off value of seropositivity. These results suggest that C. pneumoniae infection is not associated with carotid artery atherosclerosis.