Why would you want to reduce the fortified attributes? I know of some people that will go on doing other stuff for as long as possible before getting the cure, just so they have the + to the attributes.
But if you still wanna reduce the attributes, you could go pick a fight with a Bonewalker. A Lessor or standard Bonewalker have a Drain Strength and Endurance attacks while the Greater Bonewalker has a Damage Strength and Endurance attacks. If you fight the Greater Bonewalker just make sure you can restore your strength enough to get to a shrine that removes the damage spell effect.
Role-playing and anti-cheating(what I feel is cheating, anyway) reasons are why. Since I am my character and since I wouldn't want to be stuck with a disease, I get rid of it as soon as possible. Since I want to only obtain what I earn, and I want to reduce my stats to what they are supposed to be. I fixed the problem, though, using custom drain attribute on self spells, and the whole thing(buying an attribute damaging spell, making two more, and getting any needed potions while using my restore attribute spells) only costed 89 gold.