RESUMO
OBJECTIVES: To investigate plasma concentrations of Interleukin-16 (IL-16) and Interleukin-10 (IL-10) in Lebanese knee osteoarthritis (KOA) patients and to examine the association between the diet-associated inflammation and increased risk for KOA. METHODS: A total of 208 study participants were assigned to one of the 3 groups: Diagnosed Knee Osteoarthritis group (DKOA) (N = 78); Undiagnosed Knee Osteoarthritis group (UKOA) (N = 60) and controls matched on age, sex and sociodemographic characteristics (N = 70). UKOA represents KOA features before they are altered by therapeutic intervention and lifestyle modifications that follow the diagnosis. Energy-adjusted dietary inflammatory index (E-DII™) scores were calculated using 2-day 24-hour recalls. IL-10 and IL-16 were measured using commercially available sandwich enzyme-linked immunosorbent assay kits. RESULTS: The UKOA group and controls did not show any significant difference in plasma IL-16 levels (p = 0.28), whereas significantly higher levels of IL-10 were observed in the UKOA group compared to controls (21 ± 41 vs 7.5 ± 12 pg/mL; p = 0.01). The UKOA group had significantly higher IL-16 levels compared to the DKOA group (177 ± 215 vs 80 ± 57 pg/ml; p = 0.001) and significantly higher IL-10 levels compared to the DKOA group (21 ± 41 vs 8 ± 14 pg/mL; p = 0.02). Significantly higher levels of IL-16 were observed in the control group compared to the DKOA group (140 ± 161 vs 80 ± 57 pg/ml; p = 0.009) whereas the DKOA group and controls did not show any significant difference in plasma IL-10 levels (p = 0.82). Additionally, we found significantly higher E-DII scores in the UKOA group compared to controls (0.53 ± 1.028 vs 0.04 ± 1.580; p = 0.04) and in the UKOA group compared to the DKOA group (0.53 ± 1.028 vs -0.37 ± 1.899; p = 0.001). However, there was significant difference in E-DII scores between the DKOA group and controls (p = 0.16). CONCLUSIONS: Our findings indicate an association between circulating levels of IL-10 and KOA in Lebanese population, and a potential role of pro-inflammatory diet in KOA pathology. We did not find an association between circulating levels of IL-16 and KOA.