Periodontitis and systemic markers of neurodegeneration: A case-control study

Aim To investigate whether periodontitis is associated with amyloid beta (A beta) peptides and whether systemic inflammation could act as a potential mediator of this link. Materials and Methods A case-control study was designed including 75 patients with periodontitis (cases) and 75 age-balanced and gender-matched participants without periodontitis (controls). Full-mouth periodontal evaluation was performed in all participants. Demographic, clinical and behaviour data were also recorded. Fasting blood samples were collected, and serum levels of interleukin 6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), A beta(1-40) and A beta(1-42) were determined. Results Cases showed higher levels of IL-6 (8.7 +/- 3.2 vs. 4.8 +/- 0.5 pg/ml), hs-CRP (3.3 +/- 1.2 vs. 0.9 +/- 0.7 mg/L), A beta(1-40) (37.3 +/- 6.0 vs. 30.3 +/- 1.8 pg/ml) and A beta(1-42) (54.5 +/- 10.6 vs. 36.5 +/- 10.0 pg/ml) when compared to controls (all p < .001). Diagnosis of periodontitis was statistically significantly associated with circulating A beta(1-40) (beta coefficientadjusted = 6.9, 95% CI: 5.4-8.3; p < .001) and A beta(1-42) (beta coefficientadjusted = 17.8, 95% CI: 14.4-21.3; p < .001). Mediation analysis confirmed hs-CRP and IL-6 as mediators of this association. Conclusions Periodontitis is associated with increased peripheral levels of A beta. This finding could be explained by enhanced systemic inflammation that can be seen in patients with periodontitis.