Association between Major Dietary Patterns at Breakfast and Odds of Major Depressive Disorder: A Case-control Study.

Background: No study was conducted to investigate the association between principal component (PCA) derived meal-based dietary patterns and odds of major depressive disorder. We aimed to explore the association between major dietary patterns at breakfast and oddsof major depressive disorder (MDD).

Methods: A total of 200 drug-free patients with MDD and 200 healthy individuals were enrolled in this age- and sex-matched case-control study. Dietary intake was assessed using 24-hour dietary recall. PCA was applied to identify meal-based dietary patterns. The Beck Depression Inventory-II questionnaire was used for screening depression in the control group. A trained interviewer documented socioeconomic status and anthropometric measurements using standardized procedures. Conditional logistic regression was performed to find the association between patterns and MDD odds.

Results: The mean age of the participants was 45.4 ± 10.7 years and 67.5% (270 participants) were women. We identified 3 major dietary patterns at breakfast including "healthy," "oil and egg," and " legumes and condiments" patterns. High adherence to healthy dietary patterns was associated with decreased odds of MDD (odds ratio (OR), 0.55 (95% CI, 0.32, 0.94); = 0.030). Neither "oil and egg" nor "legumes and condiments" patterns were associated with MDD.

Conclusion: Healthy dietary patterns were associated with lower odds of MDD. However, no significant relationship was detected between the "oil and egg pattern" and "legumes and condiments pattern" and the odds of MDD. Recommendations for reducing the odds of MDD can be focused on increasing adherence to healthy dietary patterns at breakfast. It is recommended to conduct prospective design studies to confirm these findings.