RT Journal Article
SR Electronic
T1 Interaction of Onset and Duration of Diabetes on the Percent of GAD and IA-2 Antibody–Positive Subjects in the Type 1 Diabetes Genetics Consortium Database
JF Diabetes Care
JO Diabetes Care
FD American Diabetes Association
SP 988
OP 993
DO 10.2337/dc10-1903
VO 34
IS 4
A1 Tridgell, David M.
A1 Spiekerman, Charles
A1 Wang, Richard S.
A1 Greenbaum, Carla J.
YR 2011
UL http://care.diabetesjournals.org/content/34/4/988.abstract
AB OBJECTIVE GAD antibodies (GADA) are more common in type 1 diabetic subjects diagnosed at an older age, whereas insulinoma-antigen 2 antibodies (IA-2A) are more common in subjects with younger onset. The prevalence of both antibodies decreases with longer duration of type 1 diabetes. We evaluated the interaction between age of diagnosis (onset) and duration of diabetes on the percentage of GADA- and IA-2A–positive subjects.RESEARCH DESIGN AND METHODS Data were used from 5,020 individuals with type 1 diabetes obtained from the Type 1 Diabetes Genetics Consortium dataset. The percentages of GADA- and IA-2A–positive subjects were modeled with duration as the continuous independent variable using a modified spline.RESULTS Within the first 5 years from diagnosis, 19.4% of individuals (median age 13 years) had neither GADA nor IA-2A, and by 6 to 13 years after diagnosis (median age 18 years), 31.7% were antibody-negative. There was no significant interaction between onset of disease and duration of diabetes for IA-2A (P = 0.30). The interaction was significant for GADA (P = 0.0002), resulting from differences in subjects diagnosed at or older than age 14. For these individuals, there was no apparent effect of duration of disease on the percentage of GADA-positive subjects within the first 5 years of diagnosis.CONCLUSIONS Onset and duration of diabetes both have an important effect on antibody status. The interaction of onset and duration on GADA positivity, but not on IA-2A, suggests differences in biology. These data provide a context for clinicians to interpret results of autoantibody testing in clinical practice.