(P14-030-23) Japanese-Style Diet Is Associated With Low Prevalence of Depressive Symptoms: Japan Epidemiology Collaboration on Occupational Health Study

Objectives: Japanese diet is characterized by high consumption of fish, soy product, and green tea, each of which has been linked to better mental health. It remains elusive, however, whether the contemporary Japanese diet prevents mood disorders. The purposes of this study are to develop scores of the traditional Japanese diet and its modified one and to examine their cross-sectional associations with depressive symptoms in a large working population.

Methods: As part of the Japan Epidemiology Collaboration on Occupational Health Study, we conducted a survey in 2018-2021. Diet was assessed using a validated food frequency questionnaire (Nutrients, 2022). Based on this questionnaire, we developed scores for the traditional Japanese diet (9 items: white rice, miso soup, soy product, vegetable, mushroom, seaweed, fish, salty food, and green tea) and its modified version (11 items: whole grain instead of white rice, reverse scoring for salty food, and addition of fruit and dairy foods). Depressive symptoms were assessed using the 11-item Center for Epidemiological Studies-Depression Scale (cutoff score ≥ 9). A Poisson regression with a robust variance estimator was used to estimate the prevalence ratio (PR) and 95% confidence interval (CI) while adjusting for potential confounders.

Results: Of 12,496 participants (participation rate 74.7%), 31% reported depressive symptoms. Female sex, older age, higher educational attainment, higher leisure-time physical activity, higher job position, and being married were associated with a higher score for both scores, whereas current smoking and shift work were associated with a lower score. The adjusted PR (95%CI) of depressive symptoms for the lowest through highest quartiles of the traditional Japanese diet score were 1.00 (reference), 0.94 (0.89-0.99), 0.91 (0.85-0.97), and 0.83 (0.80-0.86), respectively, and those for the modified version were 1.00 (reference), 0.94 (0.90-0.98), 0.84 (0.81-0.88), and 0.80 (0.78-0.83), respectively.

Conclusions: Close adherence to the Japanese diet was associated with a low prevalence of depressive symptoms. The association for its modified version was somewhat stronger than that for the traditional diet.

Funding Sources: Grants from the Industrial Health Foundation, the Japan Society for the Promotion of Science KAKENHI, and the National Center for Global Health and Medicine