Background: An association between coronary heart disease (CHD) and clinically diagnosed periodontitis has been found in several epidemiological studies. However, seroepidemiologic evidence based on prospective data on this association is totally lacking.

Design: The aim of the study was to investigate serum antibodies to major periodontal pathogens for their prediction of myocardial infarction (MI) in men free of CHD at baseline.

Methods: Cases and controls were ascertained from a random population sample of 4255 men aged 30 to 59 years at baseline. The study cases included 63 men with nonfatal MI or coronary death within the follow-up time of 10 years. Age-matched control subjects (n=63) were randomly chosen from the same cohort. Serum antibody levels to two major periodontopathogenic bacteria, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, were determined.

Results: There was no significant association between the risk for MI and IgG- or IgA-class antibody levels to A. actinomycetemcomitans or IgG-class antibody levels to P. gingivalis. However, a high P. gingivalis IgA-class antibody level predicted MI independently of classical cardiovascular risk factors. The risk for MI increased by increasing quartiles of antibody levels (P for the trend 0.021). Compared with the first quartile, the multivariate odds ratios of MI in the second, third and fourth quartiles were 2.47 (95% CI 0.75-8.11), 3.30 (1.03-10.58) and 3.99 (1.22-13.10), respectively.

Conclusion: The study provides serological evidence that an infection caused by the periodontal pathogen, P. gingivalis, increases the risk for MI.