Prevalence Of Adult Onset Autoimmune Diabetes In China:A Nationwide Population-based Study

Objective:Our previous clinic-based study "LADA China Study", which initiated in June2006, aimed to determine the prevalence of LADA in China by investigating newly diagnosed T2DM patients from46centers in25cities, had reported the proportion of latent autoimmune diabetes in adult was5.9%. However, there has no report related to the prevalence of autoimmune diabetes based on the national-wide population. We took advantage of the clinical data and samples from "The China National Diabetes and Metabolic Disorders Study", and further screened islet autoantibodies, in order to investigate the prevalence of autoimmune diabetes in adults in China.Methods:"The China National Diabetes and Metabolic Disorders Study" initiated in June2007, which was a cross-sectional study based on national-wide population. A nationally representative sample of46,239adults,20years of age or older, from14provinces and municipalities participated in the study. A total of4949subjects of diabetes was diagnosed(including previously diagnosed). We selected4671diabetic subjects with integrated data, and480healthy subjects that presented normal response to the75-g oral glucose tolerance test, and screened glutamic acid decarboxylase antibodies(GADA), protein tyrosine phosphatase-like protein autoantibodies (IA-2A) and zinc transporter8autoantibodies (ZnT8A) by radioimmunoprecipitation assay.Results:1. Out of the4671patients with diabetes mellitus,310patients were positive for at least one of three autoantibodies and diagnosed with autoimmune diabetes (6.6%).2. The positivity of GAD A in patients with diabetes mellitus above the age of30was4.1%(187/4521), which was lower than that of our previous clinic-based "LADA China Study".3. There was no significant difference in prevalence of autoimmune diabetes in adult between male and female subjects(male6.4%, female6.8%, P>0.05), or between newly and previously diagnosed patients(newly diagnosed6.3%, previously diagnosed7.1%, P>0.05). The positivity of GADA in the30-39years old patients with diabetes mellitus was significantly higher than that of total diabetic population (6.2%vs4.1%,P=0.033), and was higher than that of40-49years,50-59years old patients (6.2%vs3.1%,6.2%vs3.5%, P=0.006and P=0.011).5. The prevalence of autoimmune diabetes in adult showed no significant difference among the different duration groups (0-3years6.2%,4-6years8.7%,7-10years8.5%,10years or more5.6%).Conclusion:The prevalence of autoimmune diabetes in adult of all diabetic population based nationwide population in China is6.6%.