Exploring the association between adiposity, pain intensity, and effusion-synovitis in people with knee osteoarthritis: A cross-sectional study

OBJECTIVES: To examine (i) the association of adiposity with pain intensity and/or effusion-synovitis in people with knee osteoarthritis (OA), adjusting for body mass index (BMI), and (ii) whether indicators of systemic immune inflammation (i.e., the systemic immune-inflammation index (SII) and the systemic immune response index (SIRI)) moderate the above associations. METHODS: Individuals with knee OA were sampled from the Western Ontario Registry for Early Osteoarthritis Knee Study. Total body and visceral fat percentages were measured using bioimpedance analysis, and effusion-synovitis was graded using knee ultrasonography. Multiple regression models with interaction terms were used to examine the association between fat percentages and pain intensity (linear)/effusion-synovitis (logistic), and the interaction effect of fat and SII/SIRI on pain intensity/effusion-synovitis. The analyses were adjusted for confounders (age, sex, BMI, radiographic severity of the opposite knee, and anxio-depressive symptoms). RESULTS: Data from 225 participants (mean age: 61.1 (10.9), 68% female, mean BMI: 31.7 (7.7)) were analyzed. The associations for adjusted fat and pain intensity models were as follows: total body fat: β): - 0.03 (-0.54 to 0.46) and visceral fat: β (: -0.25 (-1.03 to 0.51)., The odds ratios for adjusted fat and effusion-synovitis models were total body fat: OR): 0.98 (0.92 to 1.05) and visceral fat: OR (): 1.01 (0.91 to 1.11)). Neither the main nor the interaction effects were significant. CONCLUSION: Our preliminary results do not support an association of adiposity and its interaction with generalized inflammation with pain/effusion-synovitis adjusted for BMI. Further studies are needed.