Background: Recent data indicate that interleukin (IL)-1 polymorphism may influence the susceptibility to periodontitis and coronary heart diseases. The aim of this study was to evaluate the impact of the composite IL-1 genotype (allele 2 at IL-1A -889 and IL-1B +3954) in the association between acute myocardial infarction (AMI) and periodontitis.
Methods: One hundred four white subjects (54 patients with AMI and 50 healthy controls) were studied; each received a comprehensive periodontal examination, including measurement of periodontal probing depth (PD) and clinical attachment level (CAL). The extent of periodontitis was assessed by the percentage of sites with clinical AL >3 mm. Polymorphisms in the IL-1 gene cluster were assessed using a reverse hybridization assay.
Results: Compared to controls, mean values for PD (4.6 mm versus 3.7 mm; P <0.0001) and CAL (5.4 mm versus 4.5 mm; P = 0.0001) were significantly increased among patients with AMI. Significantly more subjects with moderate or severe periodontitis (> or =33% of sites with clinical AL >3 mm) were found in the AMI group compared to controls (31.5% versus 8%; P = 0.0016). These differences remained statistically significant after adjustment for smoking, age, and gender. No significant differences were observed in the allele frequencies of the gene loci IL-1A -889 and IL-1B +C3954 between patients with AMI and controls. Also, there was no difference in the frequency of the composite IL-1 genotype. IL-1 genotype-positive patients with AMI had slightly increased PD and AL compared to IL-1 genotype-negative patients with AMI.
Conclusions: The results confirmed an association between periodontitis and AMI but failed to detect a modifying impact of the composite IL-1 genotype. Although the IL-1 genotype was only weakly associated with compromised periodontal health, it was not associated with AMI.