The relation between Chlamydia pneumoniae infection and abdominal aortic aneurysm: case-control study.

Due to recent interest in the role of Chlamydia pneumoniae as a pathogen of the vascular system, a case-control study was conducted to investigate the association between serological evidence of infection with C. pneumoniae and the occurrence of abdominal aortic aneurysm. Detectable IgG antibody to C. pneumoniae was more common among abdominal aortic aneurysm cases than among control patients (adjusted odds ratio, 5.97; P = .08), as was detectable IgM antibody (10% vs. 0%; P = .02). These findings suggest that infection with C. pneumoniae may play a role in the pathogenesis of abdominal aortic aneurysm; therefore, further research in this area is warranted.