Psychological health mediates the association between diet and upper gastrointestinal cancer: a cross-sectional analysis from a large-scale population-based screening project

Objective: Upper gastrointestinal (UGI) cancer, including esophageal and gastric cancers, poses a significant health burden. While unhealthy dietary patterns are a recognized risk factor for UGI cancer, the complex interplay with psychological health that influences UGI cancer risk remains underexplored. The current study aimed to determine the association between dietary quality and UGI cancer, and the link with depression and anxiety symptoms. Methods: Cross-sectional data were drawn from the baseline survey of the National Cohort of Esophageal Cancer study that was conducted between 2017 and 2019 in five high-risk regions of China. Dietary quality was evaluated using the Diet Balance Index (DBI)-16. Psychological symptoms were measured with the Generalized Anxiety Disorder 7-item Scale (GAD-7) and the Patient Health Questionnaire (PHQ)-9. Eligible participants underwent endoscopy screening and suspicious cases were confirmed via pathologic biopsies. Results: A total of 434 UGI cancer cases were confirmed among 29,068 participants. Logistic regression models indicated that poor diet quality, reflected by an inadequate intake [low bound score (LBS)] and unbalanced diet [dietary quality distance (DQD)], was associated with psychological distress (e.g., LBS and anxiety: OR = 1.36, 95% CI: 1.19–1.56). UGI cancer participants had more severe psychological symptoms (e.g., anxiety and UGI cancer: OR = 1.20, 95% CI: 1.14–1.26). Path analysis further revealed that psychological symptoms significantly mediate the relationship between poor dietary quality and UGI cancer risk; specifically, anxiety symptoms mediated 27.78% of the LBS-UGI cancer link. Conclusions: The current study revealed a significant association between dietary quality and UGI cancer risk, suggesting that psychological symptoms may have a mediating role. Incorporating dietary and psychological health management into public health strategies is crucial for comprehensive cancer prevention.