Brief Summary: The use of vitamin E, vitamin C, beta carotene, and/or multivitamins may keep cancer, cardiovascular disease, eye diseases, or cognitive decline from occurring. This randomized clinical trial studied vitamin E, vitamin C, beta carotene, and/or multivitamins to see how well they work compared with placebos in preventing cancer, cardiovascular disease, eye disease, and cognitive decline in male doctors aged 50 years and older.

Detailed Description: OBJECTIVES: Primary * To determine whether vitamin E every other day reduces the risk of developing prostate cancer in older healthy male physicians. * To determine whether daily vitamin C and/or a multivitamin reduces the risk of total cancer in these participants. * To determine whether vitamin E every other day, vitamin C daily, or a multivitamin daily reduces the risk of major cardiovascular events in these participants. Secondary * To determine whether vitamin E and/or multivitamins reduce the risk of developing total cancer, colon cancer, and colon polyps in these participants. * To determine whether vitamin E, vitamin C, or multivitamins reduce the risk of myocardial infarction and stroke in these participants. * To determine whether vitamin E, vitamin C, or multivitamins reduce the risk of age-related macular degeneration or cataract in these participants. * To determine whether vitamin E, vitamin C, or multivitamins reduce the risk of early cognitive decline in participants aged 65 and over. The Physicians' Health Study II was a randomized, double-blind, placebo-controlled, factorial trial that began in 1997 and ended in 2011. It was designed to test four supplements -- (1) alternate-day vitamin E (400 international units of synthetic alpha-tocopherol) or its placebo; (2) daily vitamin C (500 mg synthetic ascorbic acid) or its placebo; (3) a daily multivitamin (Centrum Silver) or its placebo; and (4) alternate-day beta carotene (50 mg Lurotin) or its placebo -- in the prevention of cancer, cardiovascular disease, eye disease, and early cognitive decline among 14,641 male physicians aged 50 years or older. Participants were randomly assigned in a 2x2x2x2 factorial trial to receive combinations of the four active supplements or their placebos. Pills and/or packaging were provided by BASF Corporation, Pfizer (formerly Wyeth, American Home Products, and Lederle), and DSM Nutritional Products (formerly Roche Vitamins). The beta-carotene component was discontinued on March 8, 2003; the vitamin E and vitamin C components ended as scheduled on August 31, 2007; and the multivitamin component ended on June 1, 2011.