Celiac disease in children, adolescents, and young adults with autoimmune thyroid disease.

OBJECTIVE: To determine the prevalence of antibodies associated with celiac disease and biopsy-proven celiac disease in children with autoimmune thyroid disease.

STUDY DESIGN: A total of 302 patients with positive anti-thyroid antibodies were prospectively studied. Total immunoglobulin A (IgA) and tissue transglutaminase-IgA (tTG-IgA) levels were obtained. Those with a positive tTG-IgA titer were offered biopsy for definitive diagnosis of celiac disease.

RESULTS: A total of 4.6% of subjects with autoimmune thyroid disease had positive tTG-IgA titers. The prevalence of biopsy-confirmed celiac disease was 2.3%. Our population was enriched with patients with type 1 diabetes mellitus (4.3%) and Down syndrome (3.4%). Excluding individuals with these co-morbidities, the prevalence of celiac disease in autoimmune thyroid disease is 1.3%, similar to that of the general population. The positive predictive value of biopsy-proven celiac disease in patients with autoimmune thyroid disease and positive tTG-IgA titer was 54%.

CONCLUSION: The increase in prevalence of celiac disease in autoimmune thyroid disease in our study was largely caused by enrichment with co-morbidities. Without comorbidities or symptoms, screening for celiac disease may not be justified in this population. The specificity of tTG-IgA titer for the diagnosis of celiac disease was decreased in patients with autoimmune thyroid disease compared with the general population.