The JPHC study: design and some findings on the typical Japanese diet.

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.