--being a bit on the low side at the three hour point of a glucose tolerance test may point to reactive hypoglycemia, which is a fairly common situation in those who are pre-diabetic/insulin resistant--the body is still able to produce a surge of insulin to drive glucose past this resistance into the tissues and keep blood sugar levels from rising too high, but the surge often results in there being too much insulin a few hours on and blood sugar may drop into the 60's/70's before the surge subsides and glucose levels normalize in hours 4-5.

This is why I have often recommended that people get a 5-hour glucose tolerance test with starting glucose AND insulin levels drawn and then similar levels drawn every half-hour after the drink out to 5 hours. Yes, one feels like a pincushion, and it is boring (bring a book or ipod), but the pattern of glucose and insulin readings together over time is often far more illuminating than the glucose readings alone.

It has also become more evident that neuropathy, particularly small-fiber types, can occur in people with impaired glucose tolerance well before frank diabetes has been diagnosed. I've posted a number of times with lists of references from medical journals detailing this--searching here for "impaired glucose tolerance neuropathy" with my name can lead you to these if you are interested.