Longitudinal adherence to a dietary pattern and risk of depressive symptoms: the Furukawa Nutrition and Health Study.

OBJECTIVE: We explored the association of 3-year adherence to a dietary pattern based on nutrients that may be related to mood with the development of depressive symptoms in Japanese employees.

METHODS: Participants were 903 employees free from depressive symptoms at baseline and who attended the 3-year follow-up. Participants with depressive symptoms were defined as those with a score ≥16 on the Center for Epidemiologic Studies Depression Scale. Dietary patterns were derived using reduced-rank regression at baseline and at the 3-year follow-up survey using a validated, self-administered diet history questionnaire. Based on changes in dietary pattern scores between baseline and follow-up surveys, participants were categorized into four groups: Maintained high scores, improved scores, decreased scores, and maintained low scores. Logistic regression was used to estimate odds ratios of depressive symptoms according to changes in dietary pattern scores.

RESULTS: Maintaining high or improving adherence to a diet rich in vegetables, mushrooms, seaweeds, soybean products, green tea, potatoes, fruits, and fish and low in rice over 3 y was associated with a decreased risk of depressive symptoms. The multivariable-adjusted odds ratio (95% confidence intervals) of developing depressive symptoms for maintained high scores versus maintained low scores was 0.57 (0.35-0.93) and for improved scores versus maintained low scores was 0.54 (0.29-1.01). The association with the severe depressive status was more pronounced.

CONCLUSION: Maintaining high or improving adherence to a dietary pattern derived by reduced-rank regression is associated with a lower risk of depression among Japanese employees.