To investigate whether higher dietary inflammatory index (DII®) scores were associated with higher prevalence of radiographic symptomatic knee osteoarthritis in a large cohort of North American people from the Osteoarthritis Initiative database. METHODS: A total of 4358 community-dwelling participants (2527 females; mean age 61.2 years) from the Osteoarthritis Initiative were identified. DII® scores were calculated using the validated Block Brief 2000 Food-Frequency Questionnaire and scores were categorized into quartiles. Knee radiographic symptomatic osteoarthritis was diagnosed clinically and radiologically. The strength of association between divided into quartiles (DII®) and knee osteoarthritis was investigated through a logistic regression analysis, which adjusted for potential confounders, and results were reported as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: Participants with a higher DII® score, indicating a more pro-inflammatory diet, had a significantly higher prevalence of radiographic symptomatic knee osteoarthritis compared to those with lower DII® score (quartile 4: 35.4% vs. quartile 1: 24.0%; p < 0.0001). Using a logistic regression analysis, adjusting for 11 potential confounders, participants with the highest DII® score (quartile 4) had a significantly higher probability of experiencing radiographic symptomatic knee osteoarthritis (OR 1.40; 95% CI 1.14-1.72; p = 0.002) compared to participants with the lowest DII® score (quartile 1). CONCLUSIONS: Higher DII® values are associated with higher prevalence of radiographic symptomatic knee osteoarthritis.