Celiac Disease Autoimmunity in Patients with Autoimmune Diabetes and Thyroid Disease among Chinese Population

The prevalence of celiac disease autoimmunity or tissue transglutaminase autoantibodies (TGA) amongst patients with type 1 diabetes (T1D) and autoimmune thyroid disease (AITD) in the Chinese population remains unknown. This study examined the rate of celiac disease autoimmunity amongst patients with T1D and AITD in the Chinese population. The study included 178 patients with type 1 diabetes and 119 with AITD where 36 had both T1D and AITD, classified as autoimmune polyglandular syndrome type 3 variant (APS3v). The study also included 145 patients with type 2 diabetes (T2D), 97 patients with non-autoimmune thyroid disease (NAITD), and 102 healthy controls. Serum islet autoantibodies, thyroid autoantibodies and TGA were measured by radioimmunoassay. TGA positivity was found in 22% of patients with either type 1 diabetes or AITD, much higher than that in patients with T2D (3.4%; p< 0.0001) or NAITD (3.1%; P < 0.0001) or healthy controls (1%; p<0.0001). The patients with APS3v having both T1D and AITD were 36% positive for TGA, significantly higher than patients with T1D alone (p = 0.040) or with AITD alone (p = 0.017). T1D and AITD were found to have a 20% and 30% frequency of overlap respectively at diagnosis. In conclusion, TGA positivity was high in the Chinese population having existing T1D and/or AITD, and even higher when both diseases were present. Routine TGA screening in patients with T1D or AITD will be important to early identify celiac disease autoimmunity for better clinical care of patients.