Predictors of associated and multiple autoimmunity in children and adolescents with type 1 diabetes mellitus

PURPOSE: Type 1 diabetes mellitus (T1DM) is an autoimmune condition characterised by the presence of antipancreatic antibodies. The autoimmune process is also directed against other organs, most frequently against the thyroid gland, intestinal mucosa, and gastric parietal cells. METHODS: Our investigation included 121 children with T1DM with a mean age±standard deviation of 11.99±4.63 years (range, 2.0-20.0 years). We explored the frequency of associated autoimmunity; the presence of predictive factors such as current age, sex, and severity at diabetes diagnosis; T1DM duration; and family history of autoimmunity. RESULTS: Associated autoimmunity was present in 28.9% of T1DM patients. Children with associated autoimmunity were older at diabetes diagnosis (p=0.009) and had a longer diabetes duration compared to children without associated autoimmunity (p=0.044). Adolescents aged 12-20 years had a statistically significant higher chance of developing thyroid autoimmunity compared to children aged 1-5 years (p=0.019). Multiple autoimmunity (MA), T1DM, and 2 or more autoimmune diseases were present in 5.8% of the study population. All children with MA presented with ketoacidosis at diabetes diagnosis and had a higher percentage of familial autoimmunity (p=0.042). The familial autoimmunity of these patients most frequently affected ≥3 relatives (p=0.026) and was more frequently diagnosed before 5 years of age (p=not significant). CONCLUSION: Associated autoimmunity was present in almost one-third of T1DM patients. Significant associations with associated autoimmunity were longer diabetes duration, female sex, older age at diabetes diagnosis, and glutamic acid decarboxylase positivity. Predictors of MA were age <5 years at T1DM diagnosis, the presence of diabetic ketoacidosis at diagnosis, and a significant family history of autoimmunity.