IL-6 Gene Polymorphism and Periodontal disease in Diabetic Patients

Objective: Periodontal disease is a frequent complication in diabetic patients and may have an impact on glycemic control. Interleukin-6(IL-6) is a candidate cytokine and has been reported to be associated with insulin resistance and bone resorption. Hence, IL-6 may play an important role in both periodontitis and diabetes mellitus. In this study, we investigated the relationships among IL-6 gene polymorphism (-572), IL-6 level of plasma, periodontal status and glycermic control parameters in diabetic patients.

Methods: We recruited 185 unrelated Taiwanese patients with type 2 diabetes. All subjects had at least 20 or more teeth. Community periodontal index (CPI) and plaque index (PLI) were examined by trained dentists and IL-6 polymorphism and IL-6 level of plasma were determined by PCR-RFLP analysis and enzyme-linked immunoabsorbent assay respectively.

Results: There were 70% (130/185) patients with periodontitis (CPI>2) and 63.8% (118/185) patients with poor glycermic control (HbA1c>7%). The frequency of the -572C/C genotype was significantly associated with periodontitis (P=0.04). The odds ratio(OR) for periodontitis was 1.95 with 95%CI of 1.02-3.72 for diabetic patients of CC genotype compared with those of CG or GG genotype. Among those with HbA1c>7%, the OR increased to 2.46 with 95%CI of 1.04-5.86. However, no significant association was found between IL-6 level of plasma and, periodontitis, blood glucose control status and IL-6 genotype.

Conclusion: IL-6 gene polymorphism was associated with susceptibility to chronic periodontitis in a population of Taiwanese diabetic patients. In diabetic patients with poor glycemic control, those with CC genotype may have a higher risk for susceptibility to periodontitis than those with CG or GG genotype.