Type 1 Diabetes Mellitus and Associated Autoimmune Diseases in theFirst-degree Relatives of Diabetic Children: Questionnaire Based Study

Overview

Background.
Type 1 diabetesmellitus (T1DM) is associated with increased incidence of other autoimmune diseases.The shared genetic background may play a role in the disease pathogenesis. The aim of our study was to assess theprevalence of T1DM and other autoimmune disorders in the first-degree relatives of diabetic children.Methods and Results. Data were retrospectively obtained using structured questionnaires from868 diabetic childrenyounger than 18 years (434 girls and 434 boys, age 12.5±4.0, mean ±SD) and their 2704 relatives. The control groupincluded 1466 non-diabetic schoolmates and friends (796 girls, 670 boys, age 11.9±4.5) and their 4510 first-degreerelatives. In the questionnaire we asked about occurrence of thyroid and celiac disease in cases and controls, andabout occurrence of T1DM, thyroid and celiac disease in their first-degree relatives.We observed significantly higherprevalence of T1DM in fathers (4.4 % vs. 0.8 %), mothers (2.0 % vs. 0.5 %) and siblings (2.5 % vs. 0 %) of diabeticchildren compared to controls. Thyroid disease was found significantly more in diabetic children (10.0 % vs. 1.9 %)and their siblings (3.1 % vs. 1.7 %). Prevalence of celiac disease was also higher in diabetic children than in controls(3.2 % vs. 0.5 %), but it does not differ in their first-degree relatives.Conclusions. We found significantly higher prevalence of thyroid and celiac disease in T1DM children than incontrols. Targeted screening and early detection of thyroid and celiac diseases in T1DM patients are likely to benecessary. We observed an increased prevalence of T1DM and thyroid disease in first-degree relatives of diabeticchildren, however screening of autoimmune diseases associated with T1DM in the first-degree relatives remaincontroversial.

Key words:
associated autoimmune diseases, autoimmune thyroiditis, celiac disease, type 1 diabetes mellitus.