Fermented soy products intake and risk of cardiovascular disease and total cancer incidence: The Japan Public Health Center-based Prospective study.

Background/objectives: The association of fermented soy products, separately from total soy products, with cardiovascular disease (CVD) and total cancer has not been reported. We examined this association in a population-based prospective cohort study in Japan.
Subjects/methods: We studied 79,648 participants (42,788 women; 36,860 men) aged 45-74 years without a history of cancer, myocardial infarction, or stroke. Participants completed a food frequency questionnaire (1995-1998) and were followed to 2009-2012. Cox proportional hazards regression analysis was used to calculate the hazard ratios (HR) and 95% confidence intervals (CI) of incidence of CVD and total cancer according to quartiles of total soy products, nonfermented soy products, fermented soy products, miso soup, natto, total isoflavones from soy products, isoflavones from nonfermented soy products, and isoflavones from fermented soy products.
Results: In women, we observed a significant inverse association between fermented soy product intake and the risk of CVD (multivariate HR in the highest compared with the lowest quartile of fermented soy product intake: 0.80; 95% CI: 0.68, 0.95; P for trend = 0.010), and also found significant inverse associations for natto and isoflavones among fermented soy products. In site-specific analysis, we observed a similar, significant inverse association between fermented soy product intake and the risk of stroke in women. We found no significant association between any soy product and risk of CVD in men or total cancer in both sexes.
Conclusions: Intake of fermented soy products such as natto was inversely associated with the risk of CVD in women.