Vitamin D and Omega-3 Adiposity Trial (VITAL Adiposity)

The VITamin D and OmegA-3 TriaL (VITAL; NCT 01169259) is a randomized clinical trial in 20,000 U.S. men and women investigating whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (1 gram of omega-3 fatty acids) reduces the risk of developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses. This ancillary study (VITAL Adiposity) is being conducted among participants in VITAL and will examine the effect of vitamin D or fish oil on changes in body composition and adiposity (baseline compared to 2 year, as measured by anthropometric indices, total and regional body fat and adipokines) and assess whether changes in cardiovascular risk factors (lipids, glucose tolerance, blood pressure) are mediated by these parameters. How achieved 25(OH)D levels are affected by body composition and body mass will also be assessed.