The mediating role of dietary inflammatory index on the association between eating breakfast and depression: Based on NHANES 2007-2018.

Background: Depression is a significant, pervasive, global public health problem, associated with many factors, such as diet, social factors, and lifestyle habits. We aimed to evaluate the association between eating breakfast, dietary inflammatory index (DII) and depression, and to verify the mediating role of DII on the effect of eating breakfast on depression.

Methods: 21,865 participants from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018 were included in this study. Binary logistic regression and mediated effect analysis were conducted to analyze the associations between eating breakfast, DII and depression. Dietary inflammation was divided into pro-inflammatory diet and anti-inflammatory diet according to the DII.

Results: Both pro-inflammatory diet and skipping breakfast were risk factors for depression. After adjusting for covariables, compared with participants reporting breakfast in both recalls, reporting breakfast in one recall had a higher OR 95%CI (1.54(1.20, 1.98)) of depression. These associations in stratified analysis and sensitivity analysis without cardiovascular diseases (CVD) and diabetes were robust. DII mediated the association between eating breakfast and depression, the proportion of participants who reported breakfast in one recall and no recall was 26.15 % and 26.67 %, respectively.

Limitations: This was a cross-sectional study that couldn't argue for the cause-effect relationship. Moreover, the confounding factor regarding medication use was not accounted for due to limited data.

Conclusions: Skipping breakfast may increase the risk of depression by raising DII. And our study supported the essential role of regular breakfast and the anti-inflammatory diet in reducing the risk of depression.