This study investigated insulinoma-associated-2 autoantibody (IA-2A) and zinc transporter 8 autoantibody (ZnT8A) distribution in patients with type 1 diabetes (T1D) and latent autoimmune diabetes (LAD) and the autoantibodies\' association with clinical characteristics and HLA-DR-DQ genes.
This cross-sectional study recruited 17,536 patients with diabetes from 46 hospitals across China. A total of 189 patients with T1D and 58 patients with LAD with IA-2A positivity, 126 patients with T1D and 86 patients with LAD with ZnT8A positivity, and 231 patients with type 2 diabetes (T2D) were selected to evaluate islet autoantibodies, clinical phenotypes, and HLA-DR-DQ gene frequency.
IA-2A was bimodally distributed in patients with T1D and LAD. Patients with low IA-2A titre LAD had lower fasting C-peptide (FCP) (p < 0.01), lower postprandial C-peptide (PCP) (p < 0.001), and higher haemoglobin A1c (HbA1c) levels (p < 0.05) than patients with T2D. Patients with high IA-2A titre LAD were younger than patients with low IA-2A titre LAD (p < 0.05). Patients with low IA-2A titre T1D had lower FCP (p < 0.01), lower PCP (p < 0.01), and higher HbA1c levels (p < 0.05) than patients with high IA-2A titre LAD. HLA-DR-DQ genetic analysis demonstrated that the frequency of susceptible HLA haplotypes was higher in IA-2A-positive patients (p < 0.001) than in patients with T2D. Patients with high ZnT8A titre LAD had lower FCP (p = 0.045), lower PCP (p = 0.023), and higher HbA1c levels (p = 0.009) and a higher frequency of total susceptible haplotypes (p < 0.001) than patients with low ZnT8A titre LAD.
IA-2A in patients with T1D and LAD was bimodally distributed, and the presence of IA-2A could demonstrate partial LAD clinical characteristics. ZnT8A titre had a certain predictive value for islet functions in patients with LAD.

Type 1 and type 2 diabetes mellitus incur an increased risk of fracture, with a generally higher risk among individuals with type 1 diabetes. The fracture risk among individuals with latent autoimmune diabetes of adulthood (LADA) is not known. The present cohort study aimed to estimate the risk of hip and forearm fracture among individuals with LADA, alongside type 1 and type 2 diabetes, using data from the second survey of the Trøndelag Health Study (HUNT2) in 1995-97. All inhabitants aged 20 years or older (N = 92,936) were invited to attend, of whom 65,234 (70%) participated. A total of 1972 (3%) reported to have diabetes; 1399 were found to have type 2 diabetes, 144 to have LADA, and 138 to have type 1 diabetes. All participants were followed prospectively with respect to hip- and forearm fractures by linkage to the local fracture registry. During a median follow-up of 16.2 years, 2695 persons with hip fractures and 3533 persons with forearm fractures were identified. There was an increased risk of hip fracture in women with type 2 diabetes (HR = 1.51, 95% CI 1.24-1.85) and LADA (HR = 2.15, 95% CI 1.25-3.72), whereas women with type 1 diabetes did not have a significantly increased risk (HR = 2.13, 95% CI 0.89-5.14). Among men, only LADA was associated with an increased risk of hip fracture (HR = 2.69, 95% CI 1.34-5.41). There was no statistically significant association between any of the diabetes types and forearm fracture. In women with type 2 diabetes, the highest risks of hip fracture were observed among those with highest HbA1c level at baseline, longest time since diagnosis, and most visual and movement impairment. We found that individuals with LADA had an increased risk of hip fracture similar to that previously reported for individuals with type 1 diabetes, and no increased risk of forearm fracture.