I took 800 IU a day for well over a year. No effect.

I don't know what effect it has on the progression of the disease, but I had been taking 400 IU for my heart/antioxidant value, but discontinued it when recent studies showed that it might increase the potential for stroke. The nodules on my hand became tender and painful, but felt much better when I went back on Vit E (I still used the Vit E oil with aspirin rub). If you have tenderness, pain, redness associated with DC you may find that Vit E, as an anti-inflamatory will help.

I just went to my hand surgeon for my annual Kenalog shot and he remarked that he thought my nodules were smaller, but I can't really say that I've noticed them getting smaller. It may very well be that the inflamation around them has subsided and that makes them seem smaller.