Bidirectional associations between dietary diversity and depressive symptoms in Chinese adult women: A retrospective cohort study

Objective: This study aimed to examine the bidirectional associations between dietary diversity and clinical depressive symptoms in adult women, and influencing factors of clinical depressive symptoms. Methods: This longitudinal study included a total of 22,385 participants, each of whom underwent at least two data collections. We used convenience sampling to recruit women from a health management center of a general hospital in southern China from April 2015 to December 2021. They completed an online self-reported health questionnaire, which included demographic characteristics, lifestyle information, the Dietary Diversity Scale (DDS), and the Patient Health Questionnaire-9. Results: New-onset depressive symptoms and low dietary diversity were observed in this study among 1285 and 3223 participants, respectively. Negative associations were observed between baseline low dietary diversity and new-onset depressive symptoms (P < 0.05) and between baseline depressive symptoms and low dietary diversity (P < 0.001). Cross-lagged panel analysis indicated that dietary diversity negatively and prospectively predicted depressive symptoms, but vice versa (P < 0.05). Strong evidence of a nonlinear association between DDS scores and incident depressive symptoms was found (P nonlinear < 0.05) regardless of whether the variables were adjusted. Besides, age, menarche age, physical activity, sleep duration, longer sedentary behavior and other lifestyle factors were influencing factors of depressive symptoms (P < 0.05). Conclusions: The present study identified bidirectional associations between dietary diversity and depressive symptoms, and the associations were found to have a non-linear pattern. Adherence to dietary diversity and a healthy lifestyle could be effective non-pharmacological preventive measures to reduce the incidence of depressive symptoms.