Antibody levels to single bacteria or in combination evaluated against myocardial infarction

Background: Evidence is accumulating that oral bacteria are associated with myocardial infarctions (MI). We were interested in studying the differences in the association between single bacteria or bacteria in combination and the relation to C-reactive protein (CRP). Material and Methods: We examined the levels of antibodies against four major periodontal pathogens Porphyromonas gingivalis (PG), Aggregatibacter actinomycetemcomitans (AA), Tannerella forsythia (TF) and Treponema denticola (TD) and CRP in 548 men with a self-reported history of MI to 625 controls who took part in the Oslo II study in 2000. Results: The mean levels of bacterial antibodies were higher for the cases than the controls, but not significant as standard deviations were large. The level of CRP was higher in the cases than the controls (p=0.010). Logistic regression analyses comparing the upper quartile value with the lower value of one of either four antibodies (anti-AA, anti-TF, anti-TD and anti-PG) were significantly associated (p=0.032) with MI. Equivalent analyses of either three bacteria showed significant associations for anti-AA, anti-TD and anti-PG (p=0.036) and anti-AA, anti-PG and anti-TF (p=0.040). CRP showed an increased relative risk with increasing quartile value; trend, p=0.016, but not in multivariate analysis including the oral antigens. Conclusions: No single bacterium but rather combinations were related to increasing relative risk for MI independent of known cardiovascular risk factors.