The Cancer Prevention Study I (CPS-I) is a prospective mortality study of approximately 1 million adult men and women enrolled between October 1, 1959 and February 15, 1960, and followed up through September 1972. Participants were recruited into the study in 25 states by approximately 68,000 volunteers for the American Cancer Society. Enrollment was by families (households). All family members age 30 years and over were recruited if at least one participating household member was 45 years or older.
At the time of enrollment, each participant completed a four-page baseline questionnaire providing information on height, weight, demographic characteristics, personal and family history of cancer and other diseases, menstrual and reproductive history (women), occupation, diet, alcohol and tobacco use, and physical activity. Supplemental questionnaires were mailed to participants in 1961, 1963, 1965, and 1972, inquiring about cancer and changes in smoking habits. These additional questionnaires were used only to confirm vital status.
The participants' vital status was determined annually (in October) from 1960 through 1965, and again in 1971 and 1972, through personal inquiries by the volunteers. At each of these 8 follow-ups, the volunteers were asked whether their enrollees were alive or dead and the date and place of all deaths. Death certificates were obtained from State Health departments.