Chlamydia pneumoniae, Helicobacter pylori and cytomegalovirus infections and the risk of peripheral arterial disease in young women.

Sero-epidemiological case control studies have observed positive relations between infections with Chlamydia pneumoniae, Helicobacter pylori or cytomegalovirus (CMV) and the occurrence of coronary artery disease (CAD) and stroke. Moreover, positive relations between 'infection burden' and CAD and the role of inflammation have recently been described. However, the relations between infection, inflammation and the occurrence of peripheral arterial disease (PAD) have not been reported so far. We performed a multi-centre population-based case-control study, using serum samples of 228 young female PAD patients and 643 control women to determine IgG antibody titres and C-reactive protein. The odds ratios for PAD in women with serological evidence for infection with C. pneumoniae, H. pylori or CMV were 2.0 (95% CI; 1.3-3.1), 1.6 (95% CI; 1.1-2.2) and 1.6 (95% CI; 1.1-2.3), respectively. The cumulative number of infections was positively related to the risk of PAD; the odds ratio was 1.5 (95% CI; 1.0-2.4), 2.7 (95% CI; 1.6-4.4) and 3.5 (95% CI; 1.5-8.1) for women with one, two or three infections, respectively. This increased risk, related to the 'infection burden', was found again in the subgroup of women with a high CRP level, but not in the subgroup with a low CRP level. Infections might be a causal component in the development of PAD. The risk of PAD is not only related to a single pathogen in particular, but also to the cumulative number of infections. The positive relation between 'infection burden' and PAD was only found in women with a high CRP level, which indicates that inflammation might be involved in the process that leads to PAD.