Age at Development of Type 1 Diabetes– and Celiac Disease–Associated Antibodies and Clinical Disease in Genetically Susceptible Children Observed From Birth

OBJECTIVE To compare the ages and sequence in which antibodies associated with type 1 diabetes and celiac disease appear and overt diseases develop in children with an HLA-conferred susceptibility to both diseases. RESEARCH DESIGN AND METHODS We observed 2,052 children carrying genetic risks for both type 1 diabetes and celiac disease from birth until the median age of 5.7 years and analyzed diabetes- and celiac disease-associated antibodies in serum samples collected at 3- to 12-month intervals. Diabetes was confirmed by World Health Organization criteria and celiac disease by duodenal biopsies. RESULTS Altogether 342 children seroconverted to positivity for at least one diabetes-associated autoantibody and 88 to positivity for at least one celiac disease-associated antibody at the median ages of 3.0 and 1.5 years, respectively (P < 0.001). If only children with biochemically defined diabetes-associated autoantibodies against insulin, GAD, or IA-2A protein (n = 146) and children with tissue transglutaminase autoantibodies were compared (n = 86), the median seroconversion ages were 2.5 and 3.0 years (P = 0.011). Fifty-one children progressed to overt diabetes at 4.5 years and 44 children to celiac disease at 4.3 years (P = 0.257). Of the 19 children who developed both diabetes- and celiac disease-associated antibodies, 3 progressed to both diabetes and celiac disease. CONCLUSIONS Children with HLA-conferred susceptibility to type 1 diabetes and celiac disease develop celiac disease-associated antibodies mostly at a younger age or the same age at which they develop diabetes-associated autoantibodies. Clinical diabetes and celiac disease are commonly diagnosed at the same median age.