Aim:To investigate whether periodontitis is associated with amyloid beta (Aβ) 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), Aβ 1-40 and Aβ 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), Aβ 1-40 (37.3 ± 6.0 vs. 30.3 ± 1.8 pg/ml) and Aβ 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 cir-culating Aβ 1-40 ( coefficient adjusted = 6.9, 95% CI: 5.4-8.3; p < .001) and Aβ ( coefficient adjusted = 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 Aβ. This finding could be explained by enhanced systemic inflammation that can be seen in patients with periodontitis.

AimTo assess whether periodontitis is associated with cognitive decline and its progression as well as with certain blood‐based markers of Alzheimer's disease.Materials and MethodsData from a 2‐year follow‐up prospective cohort study (n = 101) was analysed. Participants with a previous history of hypertension and aged ≥60 years were included in the analysis. All of them received a full‐mouth periodontal examination and cognitive function assessments (Addenbrooke's Cognitive Examination (ACE) and Mini‐Mental State Examination [MMSE]). Plasma levels of amyloid beta (Aβ)1‐40, Aβ1‐42, phosphorylated and total Tau (p‐Tau and t‐Tau) were determined at baseline, 12 and 24 months.ResultsPeriodontitis was associated with poor cognitive performance (MMSE: β = −1.5 [0.6]) and progression of cognitive impairment (hazard ratio [HR] = 1.8; 95% confidence interval: 1.0–3.1). Subjects with periodontitis showed greater baseline levels of p‐Tau (1.6 [0.7] vs. 1.2 [0.2] pg/mL, p < .001) and Aβ1‐40 (242.1 [77.3] vs. 208.2 [73.8] pg/mL, p = .036) compared with those without periodontitis. Concentrations of the latter protein also increased over time only in the periodontitis group (p = .005).ConclusionsPeriodontitis is associated with cognitive decline and its progression in elderly patients with a previous history of hypertension. Overexpression of p‐Tau and Aβ1‐40 may play a role in this association.