Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study

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The ATBC Cohort Follow-up Study has been in place since 1994. Male smokers between the ages of 50 and 69 were recruited from southwestern Finland between April 1985 and June 1988. A total of 29,133 men were randomly assigned to one of four intervention groups: 50 mg/day alpha-tocopherol (as dl-alpha-tocopheryl acetate); 20 mg/day beta-carotene; both alpha-tocopherol and beta-carotene; or placebo. They were followed for five to eight years during the trial, until death, or 30 April 1993 when intervention was stopped (median follow-up, 6.1 years). Follow-up for endpoints was continued postintervention. Following invitation for participation and recruitment through a population-based postal survey, the trial randomly assigned 29,133 Caucasian 50-69 year old male smokers of 5 cigarettes daily to one of four intervention groups based on a 2x2 factorial design: beta-carotene (20 mg/day), vitamin E (50 mg/day, as dl-alpha-tocopheryl acetate), both agents, or placebo. At entry, medical, dietary, smoking, and occupational data were obtained, along with physical measurements, a chest x-ray, and serum and toenail samples. Diet was captured through a 276 food item dietary questionnaire that was developed and validated for the trial. Baseline serum was collected, frozen, and stored for all participants, and vitamin E, beta-carotene, retinol, and total and HDL cholesterol were determined. Follow-up serum and whole blood were collected for all active participants later in the study, as were additional serum and red blood cell samples from selected subsets. Active intervention continued for 5-8 years, with three study visits annually during which participants were asked about their health and possible subjective side effects, capsule compliance, and smoking habits since the last visit. Chest films were taken at 2-3 year intervals and at the end of the trial. All incident cancers were identified through the nationwide Finnish Cancer Registry, medical records/pathology sli