1482-P: Effect of Age on Diabetes-Specific Autoantibodies in a Large Laboratory-Based Cohort

Abstract

Type 1 diabetes mellitus (T1DM) can occur at any age, the presence of diabetes related autoantibodies predicts increased risk of disease and supports an autoimmune etiology for T1DM. Since 2017, Mayo Clinic Laboratories has been offering a comprehensive type 1 diabetes autoantibody evaluation (DM1Eval) which includes testing for 4 autoantibodies targeting glutamic acid decarboxylase autoantibodies (GAD), protein tyrosine phosphatase-like islet antigen 2 (IA-2), insulin (IAA), and zinc transporter 8 protein (ZnT8). The aim of this study was to determine the frequency of individual antibodies and antibody clusters (2, 3 or 4) stratified into 4 ages groups (children 0-17, young adult 18-35, middle aged 36-55 and older >55 years). Over a 30 month period (June 2017-Nov 2019) the DM1Eval was performed on 6,446 samples. At least 1 autoantibody was found in 3596 (56%) of all samples: 68% of children, 49% of young adults, 40% of middle aged and 41% of older adults. In patients with at least 1 antibody positive, GAD 65 antibodies were the most common in all age groups followed by ZnT8 in those <36 years or IAA antibody in those 36 and older older (Figure). The frequencies of IA2 and ZnT8 antibodies dropped significantly with increasing age strata. Autoantibody clusters of 3 or 4 antibodies were more frequently encountered in younger patients (41% of pediatric and 27% of young adult patients in contrast to just 12% in middle and older age groups). Disclosure A.R. Dahl: None. S. Pittock: None. A. McKeon: None. J. Foster: None. J. Mills: None.