Thyroid and adrenal autoimmunity in children with newly diagnosed type 1 diabetes mellitus

Objectives: Individuals with type 1 diabetes mellitus (T1DM) are at risk of further autoimmune diseases. This study aimed to identify the prevalence of thyroid and adrenal autoimmunity and dysfunction in children with T1DM. Material and Methods: A retrospective case review was conducted of children presenting to the Royal Hospital for Children, Glasgow, with newly diagnosed T1DM between 1 September 2017 and 1 September 2022. Data on thyroid peroxidase (TPO) and adrenal antibody status and function were retrieved from diagnosis until 24 May 2024. Results: 504 children were diagnosed with T1DM, with data available for 384 (53% female). Median age at T1DM diagnosis was 9.6 years (range 0.9–16.1 year). Median duration of follow-up was 4.1 years (range 1.7–6.7 years). TPO antibodies were tested at T1DM diagnosis in 364 (95%); 65 (18%) had raised TPO antibodies, with girls more likely to test positive (73%, P =