Objective: To estimate the probability of becoming high risk for cardiovascular disease among people at low and intermediate risk and not being treated for high blood pressure or lipid levels. Design: Observational study. Setting: General communities in Japan and the United States. Participants: 13 757 participants of the Tokyo health check-up study and 3855 of the Framingham studies aged 30-74 years with complete data on risk equation covariates, not receiving blood pressure or cholesterol lowering treatment, and with an estimated risk of cardiovascular disease20% using the Framingham equation. Results: At baseline most participants had10% probability of crossing the treatment threshold at one year for the 15-