Department of General Practice, Erasmus MC University Medical Center Rotterdam, Rotterdam, the Netherlands.
Department of Biostatistics and Data Science, Wake Forest School of Medicine, Winston-Salem, USA.
Osteoarthritis Cartilage. 2019 Aug;27(8):1118-1123. doi: 10.1016/j.joca.2019.04.009. Epub 2019 Apr 20.
Diet restriction and exercise form key treatments for osteoarthritis (OA) related symptoms in overweight and obese individuals. Although both interventions are known to influence systemic low-grade inflammation, which is related to pain levels and functional limitations, little is known about the potential changes in systemic inflammation as a working mechanism of diet restriction and exercise in knee OA.
Data from the Arthritis, Diet, and Activity Promotion Trial (ADAPT) were used. Through causal mediation analyses, the proportion of the effect of a 18 months diet and exercise intervention explained by the 18 months change in interleukin (IL)-6, TNF-α, soluble IL-6 receptor, soluble IL-1 receptor, CRP, and BMI were assessed, using self-reported pain and function as outcomes.
The change in inflammatory factors accounted for 15% of the total effect on pain and was totally independent of the change in BMI. The change in inflammatory factors accounted for 29% of the effect on function, with the change in BMI adding only 4% to the total mediated effect.
The change in inflammatory factors after the diet and exercise intervention was a 'medium' size mediator of the effect on pain and a 'strong' mediator for the effect on function in overweight and obese individuals with knee OA. The change in BMI added minimally to the mediated effect on function. These results highlight the relevance of changes in systemic inflammation as drivers for clinically relevant effects after diet and exercise in overweight and obese individuals with knee OA.
饮食限制和运动是超重和肥胖人群治疗骨关节炎（OA）相关症状的主要方法。虽然这两种干预措施都已知会影响全身低度炎症，而全身低度炎症与疼痛水平和功能受限有关，但对于饮食限制和运动对膝骨关节炎的全身炎症的潜在变化作为作用机制知之甚少。
使用关节炎、饮食和活动促进试验（ADAPT）的数据。通过因果中介分析，评估了 18 个月饮食和运动干预的效果中，由白细胞介素（IL）-6、肿瘤坏死因子（TNF）-α、可溶性 IL-6 受体、可溶性 IL-1 受体、C 反应蛋白（CRP）和 BMI 变化解释的比例，使用自我报告的疼痛和功能作为结果。
炎症因子的变化占疼痛总效应的 15%，且与 BMI 的变化完全独立。炎症因子的变化占功能效应的 29%，而 BMI 的变化仅增加了总中介效应的 4%。
超重和肥胖膝骨关节炎患者饮食和运动干预后炎症因子的变化是疼痛效应的“中等”大小的中介，是功能效应的“强”中介。BMI 的变化对功能的中介效应增加很小。这些结果强调了全身炎症变化作为超重和肥胖膝骨关节炎患者饮食和运动后临床相关效应的驱动因素的相关性。
