Thyroid autoantibody distribution in patients with latent autoimmune diabetes in youth: a multicenter, national survey

BACKGROUND: A high seropositive rate of thyroid autoantibodies is often reported in patients with type 1 diabetes mellitus (T1DM), latent autoimmune diabetes in adults (LADA) and type 2 diabetes mellitus (T2DM). However, the positive rate of thyroid autoantibodies in latent autoimmune diabetes in youth (LADY) patients has not been reported in China. Thus, the purpose of the current study was to clarify the thyroid autoantibody distribution in patients with LADY to provide evidence for the clinical screening of autoimmune thyroid diseases (AITD). METHODS: This nationwide, multicenter and cross-sectional study included 1,723 younger patients (<30 years old) and 2,000 older patients (≥30 years old) aged 15 to 79 years. The patients were grouped into younger T1DM (n=281), LADY (n=130), younger T2DM (n=200), older T1DM (n=287), LADA (n=129), and older T2DM (n=200) groups. Autoantibodies against thyroid peroxidase (TPOA) and thyroglobulin (TGA) prevalence were analyzed in each group. RESULTS: The prevalence of TGA or TPOA in LADY patients was similar to that in younger T1DM patients. The seropositive rate of TPOA in LADY patients was higher than that in LADA patients (36.2% vs. 23.3%, respectively; P=0.023); the risk of TPOA was higher in LADY patients than in LADA patients, even after adjusting for sex, glutamic acid decarboxylase (GADA)- and insulinoma-associated-2 (IA-2A)-positivity (OR =1.94, P=0.023). LADY patients with high GADA titers exhibited a higher frequency of thyroid autoantibodies than patients with low GADA titers did (TPOA, P=0.005; TGA, P=0.023; TPOA or TGA, P=0.004). Further analysis showed that only male patients showed a strong association between high GADA titers and thyroid autoantibodies positivity, and the association remained significant after adjustment for age (OR =11.14, P=0.025 for TGA; OR =4.99, P=0.011 for TPOA; OR =5.52, P=0.007 for TPOA or TGA). CONCLUSIONS: Routine screening for thyroid autoantibodies is recommended in LADY patients, and special clinical attention should be paid to the thyroid autoantibodies status of male patients of LADY with high GADA titers to identify patients at high risk of developing AITD.