The influence of persistent pathogens on circulating levels of inflammatory markers: a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis
1 Department of Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, CA, USA
2 Department of Epidemiology, University of Michigan School of Public Health, 1415 Washington Heights, Room 3659, Ann Arbor, MI 48109, USA
3 Department of Pathology, University of Vermont College of Medicine, Burlington, VT, USA
4 Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
5 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
BMC Public Health 2010, 10:706 doi:10.1186/1471-2458-10-706Published: 17 November 2010
Systemic inflammation is linked to cardiovascular risk, but the influence of persistent pathogens, which are conventionally dichotomously categorized, on circulating levels of inflammatory markers is not clear. Antibody levels of pathogens have not been examined in relation to inflammation.
Using data from a subsample of the Multi-Ethnic Study of Atherosclerosis, we examined circulating levels of interleukin-6 (IL-6), C-reactive protein (CRP) and fibrinogen in relation to five common persistent pathogens: cytomegalovirus, herpes simplex virus-1, Hepatitis A virus, Helicobacter pylori and Chlamydia pneumoniae. We tested the hypothesis that the number of seropositive pathogens (based on conventional cut-off points) would not be as sensitive a marker of inflammation as immune response measured by antibody levels to pathogens.
High antibody response to multiple pathogens showed graded and significant associations with IL-6 (p < 0.001), CRP (p = 0.04) and fibrinogen (p = 0.001), whereas seropositive pathogen burden did not. In multiple linear regression models, high antibody response to multiple pathogens maintained a positive association only with IL-6 (4.4% per pathogen exhibiting high antibody response, 95% CI 0.0-8.9).
High antibody response to pathogens was a more consistent marker of inflammatory outcomes compared to seropositivity alone and high antibody response to multiple pathogens was a stronger marker compared to any single pathogen.