Increased Proinflammatory Mediators Are Associated with Gingivitis in Type-2 Diabetes

Objectives: To assess whether type-2 diabetics had increased levels of local and systemic pro-inflammatory mediators and whether those higher levels are associated with enhanced clinical gingival inflammation compared to non-diabetics.

Material and Methods: A cross-sectional database consisting of 726 male and female non-smokers, aged 53 to 74 years was used. Gingival crevicular fluid (GCF) levels of IL-1b and PGE₂ and serum level of IL-6 were measured using ELISA. All participants had no probing pocket depths (PD) > 3mm. Participants with bleeding on probing (BOP) in <10% of sites were classified as healthy, while those with BOP of 10% or more were defined to have gingivitis.

Results: Approximately 53% (n=385) of the sample had gingivitis, and 11% (n=80) had type-2 diabetes. The mean age-adjusted level of GCF-IL-1b was significantly elevated in diabetic compared to non-diabetic groups (GCF-IL-1b, p=0.048; but not serum IL-6, p=0.14 or GCF-PGE2, p=0.98). All mediator levels were higher in participants with gingivitis regardless of diabetic status, and the difference was significant except serum IL-6 in the non-diabetic group. The significance of the interaction between diabetes and GCF-IL-1b or diabetes and serum IL-6 on gingivitis were borderline (p=0.09, p=0.065, respectively). Adjusted odds ratios for the association between proinflammatory mediators and gingivitis case status stratified by diabetic status are shown below.

Mediators	No diabetes	Diabetes
(separate models)	OR (95%CI)*
Serum IL-6	1.01    (0.94 –1.09)	1.61   (1.08 – 2.41)
GCF-IL-1b (100 ng/mL)	1.57    (1.26 – 1.95)	3.19   (1.48 – 6.87)
GCF-PGE2 (100 ng/mL)	1.22    (1.10 – 1.35)	1.73   (1.11 – 2.70)

Reference group: healthy individuals (n=341)

*Controlling for age, gender, education, HDL-cholesterol, fasting glucose, waist-hip ratio, hypertension, BMI, plaque scores, study center

Conclusions: Type-2 diabetes may increase the host inflammatory response to the oral biofilm, which may enhance gingivitis. Furthermore, systemic inflammation (serum IL-6) is associated with gingivitis among diabetics.