Table_2_Inflammation mediated the effect of dietary fiber on depressive symptoms.docx

Background and aimsPrevious studies showed that inflammation affects depressive symptoms. Dietary fiber may be associated with inflammation and depressive symptoms. We aimed to investigate the relationship between inflammation and depressive symptoms at different levels of dietary fiber intake and to explore whether dietary fiber affects depression through inflammation.MethodsA total of 8,430 National Health and Nutrition Examination Survey (NHANES) samples were collected between 2015 and 2018. Factor analysis was used to determine dietary patterns. Linear regression and logistic regression analysis were used to explore the relationship between nutrients, inflammation, and depressive symptoms, and the mediation analysis was conducted using the bootstrap method.ResultsFactor 3 (dietary fiber and vitamins) was inversely associated with depressive symptoms and inflammation. The upper quartile scores of the dietary inflammatory index (DII) and C-reactive protein (CRP) were associated with depressive symptoms compared with controls (DII: OR = 1.851, 95% CI: 1.267–2.705; CRP: OR = 1.737, 95% CI: 1.136–2.656). The DII score and CRP were associated with depressive symptoms in the group with low dietary fiber intake (DII: OR = 2.736, 95% CI: 1.628–4.598; CRP: OR = 2.092, 95% CI: 1.196–3.658) but not in the high dietary fiber intake group. Mediating analysis showed that CRP partially mediated the effect of dietary fiber intake on depressive symptoms (βindirect = −0.0025, 95% CI: −0.0038 to −0.0013), and the mediated proportion was 10.5%.ConclusionIn this study, we found that DII scores and CRP were not associated with depressive symptoms in participants with high dietary fiber intake, and inflammation partially mediates the effect of dietary fiber on depressive symptoms.

背景与目标：既往研究表明，炎症与抑郁症状相关。膳食纤维可能与炎症和抑郁症状有关。本研究旨在探讨不同膳食纤维摄入水平下炎症与抑郁症状之间的关系，并探究膳食纤维是否通过炎症影响抑郁。方法：收集了2015年至2018年间进行的8,430份国家健康与营养调查（NHANES）样本。采用因素分析确定膳食模式。通过线性回归和逻辑回归分析探讨营养、炎症与抑郁症状之间的关系，并采用自助法进行中介分析。结果：因素3（膳食纤维与维生素）与抑郁症状和炎症呈负相关。与对照相比，膳食炎症指数（DII）和C反应蛋白（CRP）的上四分位数得分与抑郁症状相关（DII：OR = 1.851，95% CI：1.267–2.705；CRP：OR = 1.737，95% CI：1.136–2.656）。在低膳食纤维摄入组中，DII得分和CRP与抑郁症状相关（DII：OR = 2.736，95% CI：1.628–4.598；CRP：OR = 2.092，95% CI：1.196–3.658），但在高膳食纤维摄入组中则无此关联。中介分析表明，CRP部分中介了膳食纤维摄入对抑郁症状的影响（β间接 = −0.0025，95% CI：−0.0038至−0.0013），中介比例达10.5%。结论：本研究发现，在膳食纤维摄入量高的参与者中，DII得分和CRP与抑郁症状无显著关联，炎症部分中介了膳食纤维对抑郁症状的影响。