[Studies on evaluation of risk factors of cancer by a large-scale cohort study newly organized in Japan--planning and pilot study].

A large-scale cohort study has been planned in cooperation of 22 epidemiologists in Japan since 1986. The objective of this new cohort aged more than 40, consisting the inhabitants throughout Japan is to evaluate risk factors of cancer already known and suspected agents in so rapidly changing society of Japan where age-sex contraction of population, disease pattern and lifestyle habits have remarkably changing for the last decades. The factors examined are not only social factors but also biological ones from blood, serum and other body fluids. At the same time serum bank of healthy inhabitants in Japan is established in this study.