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.

Abstract

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.

• Authors: David M Tridgell, Charles Spiekerman, Richard S Wang, Carla J Greenbaum
• Journal: Diabetes care (Diabetes Care) Vol. 34 Issue 4 Pg. 988-93 (Apr 2011) ISSN: 1935-5548 [Electronic] United States
• PMID: 21330643 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Autoantibodies
• ICA512 autoantibody
• Glutamate Decarboxylase

Topics

• Adolescent
• Adult
• Autoantibodies (biosynthesis, metabolism)
• Child
• Child, Preschool
• Cross-Sectional Studies
• Diabetes Mellitus, Type 1 (enzymology, immunology)
• Female
• Glutamate Decarboxylase (immunology)
• Humans
• Male
• Middle Aged
• Time Factors
• Young Adult