The alpha-tocopherol, beta-carotene lung cancer prevention study: design, methods, participant characteristics, and compliance. The ATBC Cancer Prevention Study Group.

The Alpha-Tocopherol, Beta-Carotene (ATBC) Lung Cancer Prevention Study was a randomized, double-blind, placebo-controlled, 2 x 2 factorial design, primary prevention trial testing the hypothesis that alpha-tocopherol (50 mg/day) and beta-carotene (20 mg/day) supplements reduce the incidence of lung cancer and possibly other cancers. Total and disease-specific mortality and incidence of various diseases and symptoms were monitored for safety. Between 1985 and 1993, 29,133 eligible male smokers aged 50 to 69 years at entry were randomized to receive daily active supplements or placebo capsules for 5 to 8 years (median 6.1 years), accumulating 169,751 follow-up years. This report describes the study design, methods, and protocol as well as the baseline characteristics and capsule compliance of the participants. The ATBC Study is the largest lung cancer chemoprevention trial conducted to date.