Questionnaire surveys A questionnaire survey was con ducted at baseline and at the 5- and 10-year follow-ups. Information on medical history and health-related lifestyles, including smoking, drinking and dietary habits, was obtained in each survey. In the present analysis, we used data from the 5-year survey, which was carried out in 1995 for cohort I and in 1998 for cohort II, as baseline. We did this because the questionnaire used for that survey contained more comprehensive information on food intake than that used for the first survey.