Our findings that vitamin D3 decreases gp91phox and p47phox expression and decreases ROS formation and especially the effects of vitamin D3 supplementation on the increase in the VDR expression support the idea that vitamin D3 supplementation can be recommended to all subjects particularly to those with the high risk for cardiovascular and cerebrovascular disorders, even when they have normal serum levels of 25-OH vitamin D. The gene discussed is CYBB; the disease is cerebrovascular disorder.