The Japan Public Health Center-based prospective Study conducted a baseline survey for 140 000 registered residents aged 40–69 years within 11 public health center areas nationwide in 1990–94. Five- and 10-year follow-up surveys were conducted to update information on lifestyle habits and health conditions. In total, 130 000 participants responded to at least one of the three questionnaire surveys, and 78 000 to all three. In addition, 60 000 participants provided blood samples on at least one of the two sampling times, and 23 000 on both. The subjects have been followed for vital status and the occurrence of cancer and other diseases. As of December 2011, 24 000 deaths have been documented, as well as 17 000 cases of cancer, 6000 cases of stroke and 1100 cases of myocardial infarction. We have tested the association between potential causal factors and the incidence of or mortality from cancer and other diseases, and published >250 papers to date. Typical dietary habits in Japan are high consumption of soy/isoflavones, fish/n-3 fatty acids, salt/salted foods and green tea, and low consumption of red meat and saturated fat. This paper briefly summarizes the observed associations of these foods/nutrients with cancer, cardiovascular diseases and diabetes. The Japan Public Health Center-based prospective Study is scheduled to conduct active follow-up for a total of 30 years, and we plan to publish additional evidence on the potential causes of a shorter life and major disease occurrence.

Background— Soy and isoflavones have been proposed to reduce the risk of cardiovascular risk factors, but their potential as preventatives for cardiovascular disease remains uncertain. We investigated the association of soy and isoflavone intake with risk of cerebral and myocardial infarctions (CI and MI). Methods and Results— To examine the association of soy and isoflavone intake with the risk of CI and MI, we studied 40 462 Japanese (40 to 59 years old, without cardiovascular disease or cancer at baseline). They completed a food-frequency questionnaire (1990–1992) and received follow-up to 2002. After 503 998 person-years of follow-up, we documented incidence of CI (n=587) and MI (n=308) and of mortality for CI and MI combined (n=232). For women, the multivariable hazard ratios and 95% confidence limits for soy intake ≥5 times per week versus 0 to 2 times per week were 0.64 (0.43 to 0.95) for risk of CI, 0.55 (0.26 to 1.09) for risk of MI, and 0.31 (0.13 to 0.74) for cardiovascular disease mortality. Similar but weaker inverse associations were observed between intake of miso soup and beans and risk of cardiovascular disease mortality. The multivariable hazard ratios for the highest versus the lowest quintiles of isoflavones in women were 0.35 (0.21 to 0.59) for CI, 0.37 (0.14 to 0.98) for MI, and 0.87 (0.29 to 2.52) for cardiovascular disease mortality. An inverse association between isoflavone intake and risk of CI and MI was observed primarily among postmenopausal women. No significant association of dietary intake of soy, miso soup, and beans and isoflavones with CI or MI was present in men. Conclusions— High isoflavone intake was associated with reduced risk of CI and MI in Japanese women. The risk reduction was pronounced for postmenopausal women.