Plasma levels of tumour necrosis factor-α in patients with chronic periodontitis and type 2 diabetes

Objectives: Studies suggest that elevated circulating tumour necrosis factor-α (TNF-α) may contribute to insulin resistance in patients with type 2 diabetes. The source of plasma TNF has been thought to be adipocytes associated with obesity, but inflammation and infection result in TNF-α production as well. Methods: We studied 46 patients with type 2 diabetes and chronic periodontitis to determine the relationship between plasma TNF-α levels and clinical measures of periodontitis, gingival crevicular fluid (GCF) interleukin-1β (IL-1β), plasma endotoxin, serum glucose, and glycated haemoglobin (HbA1c). TNF-α levels were measured using a high sensitivity enzyme-linked immunosorbent assay. Results: TNF-α showed a significant positive correlation with attachment loss (r=0.40, p=0.009), plasma endotoxin (r=0.33, p=0.03), and GCF IL-1β (r=0.33, p=0.035), but not probing depth (r=0.28, p=0.07), bleeding on probing (r=0.30, p=0.053), plaque index (r=0.22, p=0.17), serum glucose, HbA1c (r=0.10, p=0.50), or body mass index (r=0.077, p=0.62). A dose-response relationship was observed between periodontitis severity and TNF-α (p=0.012). Conclusion: The finding that chronic periodontitis is associated with plasma TNF-α levels in subjects with type 2 diabetes supports the hypothesis that periodontal infection and inflammation may contribute to insulin resistance.