Concurrent increased high sensitivity C-reactive protein and chronic infections are associated with coronary artery disease: A population-based study

BACKGROUND: An elevated serum level of C-reactive protein (CRP) is an independent predictor of coronary artery disease (CAD). Chronic infections have also been implicated in the pathogenesis of CAD.
AIMS: To investigate how concomitant chronic infection and CRP related to electrocardiogram-defined CAD in a general population.
SETTING AND DESIGN : A population-based cross-sectional study, which was conducted in three Iranian ports in the northern Persian Gulf.
MATERIALS and METHODS : For evaluation of CAD, we used Minnesota coding criteria of a 12-lead resting electrocardiogram in 1,754 subjects, aged 25 years and over, selected by cluster random sampling. Sera were analyzed for IgG antibodies to Chlamydia pneumoniae (C. pneumoniae), Herpes simplex virus type 1 (HSV-1), Helicobacter pylori (H. pylori) and cytomegalovirus (CMV) using ELISA. Measurement of CRP by a high-sensitivity CRP assay was done.
STATISTICAL ANALYSIS: Multiple logistic regression analysis was used.
RESULTS: None of the infectious agents (CMV, H. pylori, C. pneumoniae and HSV-1) showed a significant association with electrocardiogram-defined CAD after adjusting for sex and age. Elevated CRP levels did not show significant association with electrocardiogram-defined CAD independent of seropositivity to one of the four infectious agents, but concurrent elevated CRP levels (>10.0 mg/L) and anti-C. pneumoniae [OR = 1.68 (CI, 1.24-2.59; P=0.04)], H. pylori [OR = 1.98 (CI, 1.26-3.13; P=0.003)], CMV [OR = 1.66 (CI, 1.10-2.49; P=0.01)] or HSV-1 [OR=1.79 (CI, 1.18-2.72; P=0.006)] IgG antibodies were associated with prevalence of electrocardiogram-defined CAD in the general population, after adjustment for multiple risk factors, including age, sex and the components of the metabolic syndrome.
CONCLUSIONS: Beyond traditional cardiovascular risk factors, concomitant chronic infection and elevated CRP are significantly correlated with electrocardiogram-defined CAD.

Keywords
Chlamydia pneumoniae, coronary artery disease, C-reactive protein, cytomegalovirus, Helicobacter pylori, herpes simplex virus