Chapter 105 - The VITamin D and OmegA-3 TriaL (VITAL): Rationale and Design of a Large-Scale Randomized Controlled Trial

Abstract

This chapter reviews the background and potential of supplemental vitamin D3 as an agent for cancer and cardiovascular disease (CVD) prevention and provides details on how VITAL (VITamin D and OmegA-3 TriaL) will test this hypothesis. VITAL is a large-scale randomized controlled trial of vitamin D for primary prevention of cancer and CVD. The goal of the VITAL trial is to evaluate the role of vitamin D and long-chain marine omega-3 polyunsaturated fatty acid supplements in the primary prevention of cancer and CVD. VITAL will be conducted among 20,000 apparently healthy, community-dwelling participants. It features a 2X2 factorial design, and each of the active agents—vitamin D3 and fish oil (1 g/d omega-3 fatty acids as eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA), in a 1:1 ratio)—has a matching inert placebo. Thus, 5000 participants will be randomized to—active vitamin D and fish oil placebo, vitamin D placebo and active fish oil, both active vitamin D and fish oil, and both vitamin D and fish oil placebos. Consequently, VITAL will test the individual effects of vitamin D as well as joint effects on the primary outcomes over a 5-year treatment and follow-up period. This trial provides for sufficient dosing and trial duration for convincing hypothesis testing of health effects of vitamin D. Thus, VITAL will make a major contribution to knowledge on the role of both vitamin D and omega-3 fatty acid supplementation in cancer and CVD prevention.