Complex Systems

Infection and Atherosclerosis: Is There an Association? Download PDF

Mojdeh Mohtashemi
MITRE Corporation,
202 Burlington Road,
Bedford, MA 01730-1420, USA
MIT Department of Computer Science,
77 Massachusetts Avenue,
Cambridge, MA 02139-4307, USA

Brandon W. Higgs
MITRE Corporation,
7515 Colshire Drive,
McLean, VA 22102-7508, USA

Richard Levins
Harvard School of Public Health,
677 Huntington Avenue,
Boston, MA 02115, USA


The role of infectious agents in the etiology of atherosclerosis has long been implicated. More recently, however, a few epidemiological studies have provided data to dispute the positive association between infection and atherosclerosis. We present a complex system approach using the method of loop analysis to examine the association between infection and atherosclerosis under varied assumptions. We find that both positive and negative associations between infection and atherosclerosis can arise, depending on the study design, the etiological assumptions, and sources and directions of change into the system under study. Finally, we demonstrate a set of conditions under which data can be falsely interpreted as lack of any association between infection and atherosclerosis. The method of loop analysis can be used as an effective guide for designing epidemiological studies before such investigations are undertaken.