Abstract
On June 17, 2002, the Ministry of Education, Culture, Sports, Science and Technology, together with the Ministry of Health, Labour and Welfare, introduced the Ethical Guidelines for Epidemiological Research. Although studies begun before the adoption of the Guidelines are not necessarily required to conform to them, some studies have been reviewed anew by ethics review committees. In this article for the Young Investigator Award of the Japan Epidemiological Association, therefore, the author would like to offer an overview of informed consent in epidemiologic researches conducted before the introduction of the Guidelines. It is hoped that this may serve as a reference as to the contents and status of ethical considerations in these studies, for use in examinations of research that was already in progress when the Guidelines were introduced.