Ilikeplanes,
I fly for Air Canada and I can tell you that we have a few of our pilots that have diabetes.One in particular is a A320 captain who was featured in the Toronto Star I believe a couple of years ago.(not 100% sure of the newspaper)
Now I don't know what type of diabetes they have other than they have to be able to control it.
We also have a captain that I know of with a pacemaker so you would be surprised at how far Transport Canada will go to help one stay in their chosen career as long as they are safe.
Good luck