The Frequency of Undiagnosed Celiac Disease in Youth with Type 1 Diabetes and Its Association with Diabetic Retinopathy: The SEARCH for Diabetes in Youth Study

Aims. Celiac disease (CD) in adults with type 1 diabetes has been associated with increased cardiovascular risk and the earlier occurrence of diabetes-associated complications. In the Search for Diabetes in Youth study, we aimed to assess the frequency of CD and the potential for undiagnosed CD among youth with childhood onset type 1 diabetes. In addition, we assessed the burden of cardiovascular risk factors and diabetes-associated complications in youth with type 1 diabetes by CD status and IgA tissue transglutaminase autoantibody (tTGA) levels. Methods. 2,444 youths with type 1 diabetes completed a CD questionnaire and underwent tTGA testing. Integrating the celiac disease questionnaire and tTGA results for this cross-sectional analysis, participants were categorized as follows: (1) reported CD; (2) seropositive for CD (no reported CD and seropositive tTGA); and (3) type 1 diabetes only (comparison group: no reported CD and seronegative tTGA). Subanalyses were performed on those with no reported CD and tTGA ≥10x ULN, designated potentially undiagnosed CD. Cardiovascular risk factors and diabetes-associated complications were evaluated by CD status and tTGA levels utilizing a Poisson model to estimate relative risk. Results. Reported CD in youths with type 1 diabetes was 7%. Seropositivity for tTGA with no reported CD was present in 4%, and 1.2% had potentially undiagnosed CD. Youths with potentially undiagnosed CD had a 2.69x higher risk of diabetic retinopathy than comparison group. In addition, CD with tTGA <0.05 (controlled CD) was associated with lower HbA1c. Conclusions. Undiagnosed CD is likely present in youths with type 1 diabetes and potentially undiagnosed CD is associated with a higher risk of diabetic retinopathy. These findings indicate the importance of routine screening for CD in type 1 diabetes in youths.