Affiliation:
1. Translational Health Sciences, Diabetes and Metabolism Bristol Medical School, University of Bristol Bristol UK
2. Institute of Biomedical and Clinical Science, Faculty of Health and Life Sciences University of Exeter Exeter United Kingdom
3. Pacific Northwest Diabetes Research Institute University of Washington Seattle Washington USA
Abstract
AbstractAimThis study aimed to evaluate characteristics of autoimmunity in individuals who have a type 2 diagnosis and are relatives of children with type 1 diabetes.MethodsPre‐diagnosis samples (median 17 months before onset) from relatives who were later diagnosed with type 2 diabetes were measured for autoantibodies to glutamate decarboxylase 65 (GADA), islet antigen‐2 (IA‐2A), zinc transporter 8 (ZnT8A) and insulin (IAA) as well as the type 1 diabetes genetic risk score (GRS2). Associations between islet autoantibodies, insulin treatment and GRS2 were analysed using Fisher's exact and t‐tests.ResultsAmong 226 relatives (64% men; mean age at sampling 41 years; mean age 54 years at diagnosis), 32 (14%) were islet autoantibody‐positive for at least one autoantibody more than a decade before diagnosis. Approximately half of these (n = 15) were treated with insulin. GADA‐positivity was higher in insulin‐treated relatives than in non‐insulin‐treated relatives (12/18 [67%] vs. 6/18 [33%], p < 0.001). IAA‐positivity was observed in 13/32 (41%) of relatives with autoantibodies. GRS2 scores were increased in autoantibody‐positive relatives (p = 0.032), but there was no clear evidence for a difference according to treatment (p = 0.072).ConclusionThis study highlights the importance of measuring islet autoantibodies, including IAA, in relatives of people with type 1 diabetes to avoid misdiagnosis.