Associations of body weight and COVID-19 with autoimmunity in pediatric new-onset type 1 diabetes: results from the prospective DPV registry

Introduction This study analyzed the effects of the COVID-19 pandemic and body weight on islet and endocrine autoimmunity in children with type 1 diabetes (T1D). Research design and methods Data from 11 973 children and adolescents aged 0.5 to <18 years with new-onset T1D (2015–2023) from the Diabetes Prospective Follow-up Registry were evaluated. Rates of autoantibodies against beta cells (islet antigen 2 (IA2), zinc transporter 8 (ZnT8), glutamic acid decarboxylase (GAD), insulin), thyroid, transglutaminase (TGA), and adrenals were assessed. Logistic regression models adjusted for age and sex examined associations with COVID-19 and body mass index (BMI). Results 6136 (51%) children were diagnosed with T1D before, and 5837 (49%) after the beginning of the COVID-19 pandemic. Beta-cell autoantibodies were present in 94.3%, thyroid autoantibodies in 7.7%, TGA autoantibodies in 8.3%, and adrenal autoantibodies in 5.6%. During versus before COVID-19, IA2 and GAD autoantibody positivity significantly increased (63.3% vs 60.5%, p=0.002, and 65.9% vs 64.0%, p=0.04, respectively), ZnT8 autoantibodies declined (68.0% vs 71.9%, p=0.002), while insulin autoantibodies remained unchanged (p=0.06). Prevalence of IA2, ZnT8, and insulin, but not GAD autoantibodies, showed positive associations with BMI. Thyroid and TGA autoantibodies were not related, while adrenal autoantibodies were negatively related to the pandemic. Conclusions The COVID-19 pandemic and body weight influenced autoimmunity in children with T1D. The rise in IA2 autoantibody positivity may suggest a faster progression from pre-existing autoimmunity to clinical disease. The pandemic did not appear to trigger associated endocrine autoimmunity.