Identification of autoimmune type 1 diabetes and multiple organ-specific autoantibodies in adult-onset non-insulin requiring diabetes in China: a population based multicenter national wide survey.

AIMS: We previously reported in China, using a hospital-based national survey, a high frequency of adult-onset autoimmune diabetes. Here, in a population-based, multicenter nation-wide study, in phenotypic type 2 diabetes (T2D) patients, we investigate the prevalence of adult-onset autoimmune diabetes (ADM) and predisposition to autoimmune diseases by quantifying serum organ-specific autoantibodies MATERIALS AND METHODS: We included a nationally representative sample of 46 239 adults aged 20 years or older from 14 provinces, of whom 4671 had diabetes plus 1000 control subjects with normal glucose tolerance (NGT). Participants were screened centrally for autoantibodies to glutamic acid decarboxylase (GADA), protein tyrosine phosphatase-like protein (IA2A), and zinc transporter isoform-8 (Znt8A) and designated ADM where positive. We then assayed autoantibodies to thyroid peroxidase (TPOA), tissue transglutaminase (tTGA), and 21-hydroxylase (21-OHA) in randomly-selected subjects with ADM and age-, sex-matched non-ADM T2D controls plus NGT controls RESULTS: Post-normalization, standardized prevalence of ADM was 6.0 (5.3-6.8) % in initially non-insulin-requiring adult-onset diabetes subjects, corresponding to 6 million adults in China, in whom adjusted antibody positivity was TPOA 16.3(10.8-21.8) %, tTGA 2.1(0.0-4.2) %, and 21-OHA 1.8 (-0.2-3.8) %. Those GADA-positive ADM subjects had high risk for TPOA positivity (odds ratio 2.39; p=0.0031) and tTGA positivity (6.98; p=0.027), while those positive for IA2A had high risk for tTGA positivity (19.05; p=0.001).

CONCLUSIONS: A proportion of phenotypic T2D patients in China have adult-onset autoimmune diabetes with diabetes-associated autoantibodies and they may be at risk of developing other organ-specific autoimmune diseases. Therefore, it may be clinically relevant to consider screening such Chinese populations. This article is protected by copyright. All rights reserved.