The traditional Japanese dietary pattern and longitudinal changes in cardiovascular disease risk factors in apparently healthy Japanese adults

Purpose Few epidemiological studies have assessed the relationship between the traditional Japanese dietary pattern and longitudinal changes in cardiovascular disease risk factors among Japanese people. We designed a 3-year longitudinal study of 980 subjects living in Japan to evaluate how the Japanese dietary pattern is related to longitudinal changes in well-recognized risk factors for cardiovascular disease among apparently healthy Japanese adults. Methods Dietary consumption was assessed via a validated food frequency questionnaire. Principal component analysis was used to derive three major dietary patterns—“Japanese,” “sweets-fruits-cooked wheaten food,” and “Izakaya (Japanese Pub)” from 39 food groups. Results After adjustment for potential confounders, the mean (95 % confidence interval) for the change per year in diastolic blood pressure for men, systolic blood pressure, and diastolic blood pressure for women related to the “Japanese” dietary pattern factor score tertiles were 0.89 (0.10, 1.68), 2.25 (0.19, 4.31), and 0.75 (−1.00, 2.50) for the lowest tertile, 0.77 (−0.02, 1.56), 1.01 (−1.13, 3.15), and 0.44 (−1.38, 2.26) for the middle tertile and − 0.04 (−0.81, 0.72), −0.48 (−2.52, 1.56), and −0.77 (−2.51, 0.96) for the highest tertile (trend P value = 0.03, <0.01, and 0.04, respectively). A significant detrimental relationship was found between the “Izakaya (Japanese Pub)” pattern factor score tertiles and the longitudinal change in serum triglyceride concentration only in men (trend P value = 0.02). Conclusions Greater adherence to a traditional Japanese diet was independently related to a decreased change every year in diastolic blood pressure in men and women and in systolic blood pressure in women over a 3-year follow-up period. The findings suggest that the “Japanese” dietary pattern appeared to be related to a fall in blood pressure, which might have a beneficial effect on cardiovascular disease. A randomized trial is required to clarify the underlying mechanism.