No Contribution of GAD-65 and IA-2 Autoantibodies around Time of Diagnosis to the Increasing Incidence of Juvenile Type 1 Diabetes: A 9-Year Nationwide Danish Study

Abstract EN

Aims.

A new perspective on autoantibodies as pivotal players in the pathogenesis of type 1 diabetes (T1D) has recently emerged.

Our key objective was to examine whether increased levels of autoantibodies against the β-cell autoantigens glutamic acid decarboxylase (isoform 65) (GADA) and insulinoma associated antigen-2A (IA-2A) mirrored the 3.4% annual increase in incidence of T1D.

Methods.

From the Danish Childhood Diabetes Register, we randomly selected 500 patients and 500 siblings for GADA and IA-2A analysis (1997 through 2005).

Blood samples were taken within three months after onset.

A robust log-normal regression model was used.

Nine hundred children and adolescents had complete records and were included in the analysis.

Cochran-Armitage test for trend was used to evaluate changes in prevalence of autoantibody positivity by period.

Results.

No significant changes in levels of GADA and IA-2A were found over our 9-year study period.

No trends in autoantibody positivity—in either patients or siblings—were found.

Levels of GADA and IA-2A were significantly associated with HLA risk groups and GADA with age.

Conclusion.

The prevalence of positivity and the levels of GADA and IA-2A have not changed between 1997 and 2005 in newly diagnosed patients with T1D and their siblings without T1D.