Associations of Inflammatory Markers with Subjective Measures of Knee Osteoarthritis and Dietary Inflammatory Index Score ^†

Abstract

Osteoarthritis (OA) is a leading cause of disability in older adults worldwide. This study aimed to determine the associations between inflammatory markers, dietary intake and OA symptoms and pain. Understanding these associations has the potential to improve OA diagnostic and monitoring outcomes. Data from the ROAM (Researching Osteoarthritis and GreenShell Mussels) study collected from adults 55–80 years screened for OA signs and symptoms (n = 107, 65.7 years ± 6.34, 69% female) were assessed for associations between serum inflammatory markers (pg/mL), dietary inflammatory index (DII) scores and participants’ subjective measures of OA pain and symptoms. These included the Knee Injury and Osteoarthritis Outcome Score questionnaire (KOOS) subscales: pain (P), symptoms other than pain (S), function in activities of daily living (ADL), function in sports/recreation (SP) and quality of life (QoL); Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP); Visual Analogue Scales (VAS) of pain (VAS1) and symptoms (VAS2). The DII score was determined from a food frequency questionnaire and based on 34 components. The inflammatory marker IL-23 was negatively associated with all the KOOS subscales P: β coefficient −0.18, (95%CI −0.31, −0.04), S: −0.31 (−0.48, −0.14), ADL: −0.20 (−0.34, −0.05), SP: −0.43 (−0.72, −0.15) and QoL: −0.28 (−0.48, −0.08) and was positively associated with VAS measures, VAS1: 0.36 (0.17, 0.55) and VAS2: 0.25 (0.002, 0.50). MCP-1 was negatively associated and IL-12 was positively associated with KOOS P: −0.14, (−0.28, −0.01) and 0.23 (0.07, 0.40), respectively. IL-17 was positively associated with KOOS SP: 0.45, (0.14, 0.77), and IFN-α2 was positively associated with VAS1: 0.24 (0.003, 0.48). ICOAP was not associated with inflammatory markers. Inflammatory markers and subjective measures were not associated with DII. The levels of IL-23, MCP-1 and IFN-α2 increase as the symptoms worsen, while the levels of IL-12 and IL-17 increase as the symptoms improve. These markers may be useful as diagnostic and assessment tools, however, further research is needed to confirm their exact roles in OA.