A randomized trial of aspirin and β-carotene among U.S. physicians

摘要: The Physicians' Health Study is a randomized, placebo-controlled, double-blind clinical trial underway in the United States to assess effects of aspirin (325 mg q.o.d.) on total cardiovascular mortality, and beta-carotene (50 cancer incidence. participants are 22,071 U.S. male physicians between ages 40-84 years. design study 2 x factorial, which enables us address two important research questions simultaneously. conducted entirely by mail, involves sending calendar packs drugs questionnaires health status compliance, initially at six-month then annual intervals. Compliance follow-up rates date excellent. large size trial, its simple design, use highly motivated, dedicated, health-conscious should allow perform definitive tests whether low-dose consumption reduces mortality decreases incidence healthy population.