Association between Digestive Diseases, Nighttime Sleep, and Depressive Symptoms among the Middle-aged and Elderly Adults: A Mediation Analysis

Backgrounds: As the population ages, the relationship among digestive diseases, nighttime sleep duration, and depressive symptoms in middle-aged and elderly adults, especially sleep's mediating role, remains unclear, thus prompting research. Aims To explore how nighttime sleep duration mediates between digestive diseases and depressive symptoms in this group, aiming to guide clinical treatment of related depression. Methods Using 2015–2020 China Health and Retirement Longitudinal Study (CHARLS) data, we applied difference, Spearman correlation, and multivariate logistic regression analyses. A mediating effect model was set up and tested via the Bootstrap method. Results Digestive diseases had a 23.05% prevalence rate, and depressive symptoms had a 35.90% detection rate. Both digestive diseases (OR = 1.55, 95% CI: 1.38–1.73) and insufficient nighttime sleep (OR = 2.17, 95% CI: 1.97–2.40) significantly affected depressive symptoms. The model showed that insufficient nighttime sleep had a partial mediating effect. Discussion Clinically, treating relevant patients requires a holistic approach with an emphasis on sleep. Future research should use objective measures and longitudinal studies to clarify mechanisms and causalities. Conclusion Digestive diseases can cause insufficient sleep, promoting depressive symptoms. Clinicians should not overlook sleep quality when treating digestive patients with comorbid depression, as improving sleep may relieve symptoms.