BACKGROUND: The association between periodontitis and systemic diseases, including cardiovascular diseases and diabetes mellitus (DM), has been recognized repeatedly. Paraoxonase-1 (PON-1) is involved in the prevention of atherosclerosis, and decreased enzyme activity in patients with DM has been shown. The aim of this study is to investigate a possible correlation between decreased PON-1 activity and the association between impaired glucose metabolism or DM and periodontitis.

METHODS: PON-1 phenotype distribution and enzyme activities were characterized by measuring the hydrolysis of phenylacetate and paraoxon in serum samples of 87 patients with type 2 DM and 46 patients with pre-DM showing impaired fasting plasma glucose and/or impaired oral glucose tolerance. The control group comprised 64 individuals with normal fasting plasma glucose and normal glucose tolerance. Altogether, 154 study participants were available for complete clinical periodontal examination.

RESULTS: No difference in periodontitis prevalence existed between the study groups. However, patients with DM had an increased risk of suffering from generalized periodontitis (adjusted odds ratio = 4.05; 95% confidence interval = 1.24 to 13.18; P = 0.02), and their PON-1 activity was reduced compared to controls. In contrast, patients with pre-DM showed neither an increased periodontitis risk nor an impaired paraoxonase status. PON-1 was not associated directly with periodontitis. Nevertheless, concerning patients with DM, poor oral hygiene, male sex, and PON-1 phenotype were found to be significant predictors for periodontitis extent.

CONCLUSIONS: Type 2 DM, but not a prediabetic state, increases the risk of generalized periodontitis. PON-1 status in patients with type 2 DM may contribute to this association.