The study, "Shared and Distinct Genetic Variants in Type 1 Diabetes and Celiac Disease," concludes that "A genetic susceptibility to both type 1 diabetes and celiac disease shares common alleles. These data suggest that common biologic mechanisms, such as autoimmunity-related tissue damage and intolerance to dietary antigens, may be etiologic features of both diseases." This may help to address the question of why there is an "association" between celiac disease and Type 1 diabetes.
From Science Daily's coverage:
Professor David van Heel, from Barts and The London School of Medicine and Dentistry, said: "These findings suggest common mechanisms causing both coeliac and type 1 diabetes - we did not expect to see this very high degree of shared genetic risk factors."Note that a 2006 study published in Diabetes Care found that 12.3% of children with juvenile diabetes also had celiac disease, and recommended that all children with juvenile diabetes be tested for celiac disease.
Richard A. Insel, MD., Executive Vice President, Research, at JDRF, said: "These studies demonstrate that type 1 diabetes and celiac disease share far greater genetic overlap than had been appreciated, which helps explain the high prevalence of both diseases occurring simultaneously in an individual, and provide new avenues for understanding the cause and mechanisms of both diseases."