--that if one has frank diabetes and neuropathy, doctors tend to assume that the former caused the latter. That should not be assumed, though--it's lazy doctoring. Not all diabetics get neruopathy (though many do); it's certainly possible to have neuropathy from some other cause.

On the other hand, many doctors still don't know that glucose dysregulation short of frank diabetes--impaired glucose tolerance--can also result in neuropathy. Too many doctors still think that one has tohave diabetes for a while to develop neuropathy. (I have several threads on Neurotalk in which I've compiled lists of studies that demonstrate this--you can easily seach for them with my name and the term "impaired glucose tolerance").

The general mechanism for neuropathic damage due to glucose dysregulation involves excess nitric oxide production and oxidative damage tot he nerve fibers. There are a lot of articles that detail this--one of the best researchers in this area is Dr. Aaron Vinik, who has written extensively about the process of nerve damage (I have a paper of his describing autonomic neuropathy in diabetics in the Stickies).