Association of periodontitis with radiographic knee osteoarthritis

Background: To examine whether periodontitis is associated with the presence and severity of radiographic knee osteoarthritis (OA). Methods: Using data from the Korea National Health and Nutrition Examination Survey between 2010 and 2013, participants over the age of 50 were included in this study. Dental examinations and knee radiographs are performed in participants aged ≥50 years in this cohort. Periodontitis was defined using the community periodontal index, which was determined by measuring periodontal probing depth. The defini-tion of radiographic knee OA was based on the Kellgren-Lawrence (K-L) grading system, which determined a K-L class ≥2 to be radiographic knee OA. The associa-tions between periodontitis and presence and severity of radiographic knee OA were examined using logistic regression analyses. Results: Among 7969 total participants, 965 men and 2078 women had radiographic knee OA. Periodontitis was observed in 1,185 (39.4%) people among those who had radiographic knee OA. Periodontitis (adjusted odds radio [aOR] 1.21, 95% confi-dence interval 1.05 to 1.40) was associated with radiographic knee OA after adjusting for variables including age, sex, body mass index, socioeconomic status, diabetes, and dental status. Participants were more likely to have radiographic knee OA as the severity of periodontitis increased (non-severe periodontitis, aOR 1.14 [0.98 to 1.32]; severe periodontitis, aOR 1.47 [1.17 to 1.85]). Moreover, the presence of periodontitis significantly increased with an increasing K-L class (class 1, aOR 1.30 [1.09 to 1.54]; class 2, aOR 1.32 [1.08 to 1.60]; class 3, aOR 1.39 [1.14 to 1.70]; class 4, aOR 1.45 [1.11 to 1.90]). Conclusion: Periodontitis is associated with the presence and severity of radiographic knee OA.