Dietary inflammatory index is associated with pain intensity and some components of quality of life in patients with knee osteoarthritis

Objectives We aim to measure dietary inflammatory index (DII) and its association with functional status, pain intensity and quality of life (QOL) in patients with knee osteoarthritis (KOA). Dietary information from 220 qualified patients with KOA was collected by a 168-item food frequency questionnaire. The functional status, pain intensity and QOL were evaluated by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, Visual Analogue Scale (VAS) and SF36 questionnaire respectively. Results Linear regression analysis showed that the DII was significantly associated with VAS (p = 0.040; beta = 0.151), and physical function (p = 0.039; beta = - 0.184), emotional wellbeing (p = 0.048; beta = - 0.158) and pain (p = 0.020; beta = 0.161) scales and physical health (p = 0.047; beta = 0.110) subscale of QOL after adjusting for age, sex, body mass index, and physical activity. There was no significant differences concerning WOMAC across the DII tertiles with and without adjustment to probable confounders (P-trend = 0.091 and 0.181, respectively). After adjustment, a significantly increased severe pain odds was observed in the highest tertile of DII score in comparison with the lowest tertile (OR tertile(3 vs. 1) = 1.55, 95% CI 1.04-2.31; P-trend = 0.04).