Association of Dietary Inflammatory Index (DII) and depression in the elderly over 55 years in Northern China: analysis of data from a multicentre, cohort study

OBJECTIVES: Our study aimed to assess the association between the Dietary Inflammatory Index (DII) and depression in the elderly over 55 years in Northern China. METHODS: We analysed the data of 2022 Chinese adults aged 55 and over from a community-based neurological disease cohort study from 2018 to 2019. A validated semiquantitative food frequency questionnaire was used to assess eating habits at the time of inclusion. Multiple logistic regression was used for analysis, and social demographics, lifestyle and health-related factors were adjusted. RESULTS: Among the included population, the prevalence of depression was 23.39%. Mean (SD) and range of the DII in the included population were 1.70 (1.42) and −5.20 to +5.68. The risk of depression was significantly higher in participants in the most pro-inflammatory group (quartile 4) than in the participants in the most anti-inflammatory group (quartile 1) (OR 1.53; 1.37 to 1.82; p-trend=0.01). The subgroup analysis of body mass index (BMI) showed that there is a significant association between DII and the risk of depression in overweight and obese people (p＜0.05). The restricted cubic spline results show that the OR value of depression possesses an upward trend with the increase of the DII score. CONCLUSIONS: Aged patients with depression present a higher potential for dietary inflammation. Pro-inflammatory diets might increase the risk of depressive symptoms. Further research in different populations is crucial to confirm the association between DII and depression.