Aim: The aim of this study was to investigate whether genetic polymorphism in certain cytokine and receptor molecule genes and diabetic status associate with the extent of periodontal disease in type 1 diabetes mellitus (DM).
Material and methods: Eighty patients with type 1 DM participated. Visible plaque, bleeding on probing (BOP), probing pocket depth (PD) and attachment level (AL) were examined clinically and glycosylated haemoglobin (HbA1c) levels were used to assess the glycemic control of DM. CD-14, IL-6, TNF-alpha, IL-10, IL-1alpha, IL-1beta and TLR-4 gene polymorphisms were studied using the polymerase chain reaction (PCR).
Results: The 3-year HbA1c was good (<7.5%) in 16%, acceptable (7.5-8.5%) in 36% and poor (>8.5%) in 48% of the subjects. IL-6(-174) genotype and 3-year GHbA1c associated significantly with BOP and PD>or=4 mm, subjects with the GG genotype of the IL-6(-174) exhibiting more severe periodontal disease than those with the GC/CC genotype. After stratification by IL-6 genotype, associations between the extent of periodontal disease and 3-year HbA1c levels remained significant in subjects carrying the GC/CC but not the GG genotype.
Conclusions: In addition to the HbA1c level, the IL-6(-174) genotype is a significant susceptibility factor for periodontal disease among type 1 diabetics.