Japanese Diet Index Score and Cause-Specific Mortality in Japanese Men and Women: The Japan Public Health Center-Based Prospective Study.

Background: Previous research has found that the Japanese dietary pattern is associated with lower mortality risk. However, the Japanese diet has been changing, such as increased intake of coffee and dairy products and reduced salt intake, which may affect the long lifespan of Japanese people.

Objectives: We investigated the association between adherence to the new low salty food Japanese diet, with the addition of components of dairy products, coffee and salty foods, and all-cause and cause-specific mortality.

Methods: We included 93,049 participants aged 45-74 y without serious disease who were enrolled in a population-based prospective study. The score for adherence to a traditional Japanese Diet Index score (T-JDIs), consisting of 13 components (high intake of rice, miso soup, seaweeds, pickles, vegetables, non-salty seafood, salty seafood, green tea, fruits, soy products, mushrooms, salt by seasoning, and low intake of beef and pork) was assessed using energy-adjusted median intakes. We created low salty food JDIs (LS-JDIs) with lower salty food intake. In addition, scores of coffee and dairy products were added as new JDIs and new LS-JDIs (NLS-JDIs, 15-component). With the four JDIs, hazard ratios and 95% confidence intervals for all-cause and cause-specific mortality were estimated using a Cox proportional hazards model.

Results: During a median follow-up of 18.9 y, we documented 23,338 deaths. An inverse association was found between higher adherence to four JDIs and all-cause and cardiovascular disease (CVD) mortality in both genders. Especially for men, the point estimate with the highest adherence to NLS-JDIs was lower for all-cause and CVD mortality than that of T-JDIs.

Conclusions: High adherence to all JDIs was associated with lower all-cause mortality in both genders. Especially, high adherence to NLS-JDIs was decreased with all-cause and CVD mortality risk more than that of T-JDIs in men.