The VITamin D and OmegA-3 TriaL (VITAL; NCT 01169259) is a randomized clinical trial in 25,871 U.S. men and women investigating whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor® fish oil, 1 gram) 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 is being conducted among VITAL participants and will examine whether vitamin D or fish oil have effects upon A) autoimmune disease incidence, B) biomarkers of systemic inflammation, and C) chronic knee pain. Blood samples at baseline and in follow-up will be collected in a randomly selected subcohort of 1500 individuals and analyzed for changes in biomarkers of systemic inflammation: C-reactive protein, interleukin-6, and tumor necrosis factor-receptor 2. Approximately 1300 individuals with chronic, frequent knee pain will be followed with annual questionnaires to evaluate the effects of the supplements on chronic knee pain.
As for the parent trial, VITamin D and OmegA-3 TriaL (VITAL; NCT 01169259). Individuals with chronic, frequent knee pain at study baseline will be followed as a subcohort. Trial enrollment complete.
