I am 41 years old and IAA and ICA (islet cell antibodies) positive, but IVGTT [intravenous glucose tolerance test] normal. What is the probability that I will develop diabetes at five years and beyond that?

To begin with, I think you have what is now called LADA or Late Autoimmune Diabetes in Adults. So far, there aren’t any life tables to predict insulin dependence as there are for younger age groups. As it is, it might be twenty years before you develop overt diabetes especially if you watch your weight and take plenty of exercise. However, two factors might reduce this expectation. One would be if you also had anti-GAD antibodies and the other would be if the ICA antibody test was for the newer ICA512 or was the old immunofluorescence technique. You might also ask your doctor whether the IVGTT was normal just for glucose or whether the one- and three-minute insulin levels were also within normal limits.

DOB
Additional comments from Lois Schmidt Finney, diabetes dietitian:

It sounds as though this testing was done as part of the Diabetes Prevention Trial-type 1 (DPT-1). If so, I would suggest you speak with the study coordinator for the Memphis site for a more thorough explanation.

LSF