The ATBC Study
Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study:
The ATBC Study is a cohort of male smokers (aged 50-69 years) recruited in 1985-1988. The participants were screened from the total male population aged 50-69 years living in southern and western Finland (N = 290,406) through a postal questionnaire on theirg habits and willingness to participate. Smokers of at least 5 cigarettes per day and willing to participate were invited to the local study center for further evaluation of their eligibility. Men were excluded due to a history of cancer or serious disease limiting their ability to participate or use of excess vitamin supplements. In all, 29,133 men were randomized to receive in a controlled trial design either alpha-tocopherol, or beta-carotene, or both, or placebo, and of them 99.9% donated a baseline serum sample (Round 1). In 1986-1993 a random intermediate serum sample was collected from 3701 participants (12.7%) known as Round 2. A whole blood sample was collected in 1992-1993 from 70.2% of the original cohort comprising 20,167 participants (Round 3). Men were prospectively followed up for cardiovascular and cancer endpoints until 2004 using record linkage to national Hospital Discharge Register, Cancer Registry, and Register of Causes of Death with validation described in (1, 2, 3).