Dietary inflammatory index and depression risk in patients with chronic diseases and comorbidity

The coexistence of depression and chronic diseases can lead to greater disability and increased mortality. The objective of this study was to examine the association between Dietary Inflammatory Index (DII) and depression in patients with chronic diseases and comorbidity.Multivariable logistic regression analysis was used to investigate the relationship between DII and depression. Dose response relationship was analyzed using a generalized additive model with the smoothing plot.A total of 7870 chronic diseases patients were enrolled. In multivariate model, the highest quintile of DII was associated with increased risk of depression in patients with diabetes (OR:1.73, 95CI%: 1.17, 2.57), hypertension (OR:1.93, 95CI%: 1.47, 2.52), coronary heart disease (OR:2.65, 95CI%: 1.18, 5.94). The dose response relationship curve suggested the DII tended to be linearly associated with depression in patients with chronic diseases and comorbidity, and the ORs for risk of depression increased with the increase of DII. Furthermore, in patients had at least one chronic comorbidity, the subgroup analysis results showed that those who age<60 years or male participants had higher risk of depression, with ORs (95% CIs) of 2.60 (1.81, 3.74) and 2.51 (1.65, 3.81), respectively.The current study demonstrates that a higher DII is associated with an increased risk of depression in participants with chronic diseases and comorbidity, especially among those less than 60 years and men. Considering diet as a modifiable factor, limiting pro-inflammatory diet or encouraging anti-inflammatory diet may be an effective way to prevent depression and reduce depressive symptoms.