Low levels of 25-hydroxyvitamin D have been associated with higher risk for depression later in life, but there have been few long-term, high-dose large-scale trials.. Randomized assignment in a 2βΓβ2 factorial design to vitamin D3 (2000 IU/d of cholecalciferol) and fish oil or placebo; 9181 were randomized to vitamin D3 and 9172 were randomized to …