Background: The prevalence of autoimmune disorders is increased in patients with celiac disease (CD), and it is unknown whether their first-degree relatives also have a high risk of autoimmune disorders.
Methods: To assess the prevalence of autoimmune diseases in first-degree relatives of CD patients, the authors looked for autoimmune disorders in 225 first-degree relatives of 66 children with CD (group A) and in 232 first-degree relatives of 68 healthy children (group B). For both groups, serologic screening for CD was performed through antiendomysium (EMA) and tissue transglutaminase autoantibodies (tTGAA). EMA- and tTGAA-positive subjects were offered an intestinal biopsy. The age at onset of autoimmune diseases was also recorded in group A.
Results: The prevalence of autoimmune disorders was significantly (P = 0.028) higher in group A (11 of 225, 4.8%) than in group B (2 of 232, 0.86%). In relatives of CD patients, the prevalence increased with age (chi2 for trend, 43.5; P < 0.0001). Serologic screening for CD was only positive in group A (15 of 225 subjects). An intestinal biopsy was performed in 13 of these 15 relatives (2 refused biopsy). Eleven of 13 had flat mucosa, with subclinical or silent forms of CD. The prevalence of autoimmune diseases in the EMA- and tTGAA-positive relatives of CD patients was significantly higher (3 of 15, 20%; P = 0.028; odds ratio, 6.3; 95% CI, 1/0.21-1/0.11, 4.9-7.6) than in those who were EMA and tTGAA negative (8/210, 3.8%).
Conclusions: The first-degree relatives of CD patients have an increased risk of autoimmune diseases, most likely connected with unrecognized subclinical or silent forms of CD.