Further logistic regression analysis demonstrated that positivity for TSPAN7A (OR 2.87, p = 0.034), disease duration (OR 1.83, p = 0.019) and GAD antibody titre (OR 2.67, p = 0.009) were risk factors for beta cell function in LADA, while BMI (OR 0.34, p = 0.001) was a protective factor.
The association was stronger in LADA with low GAD antibody (GADA; <median) (OR 4.25; 95% CI 2.76, 6.52) but present also in LADA with high GADA (OR 2.14; 95% CI 1.42, 3.24).
We aimed to improve the genetic characterisation of LADA and hypothesised that type 2 diabetes-associated gene variants also predispose to LADA, and that the associations would be strongest in LADA patients with low levels of GAD autoantibodies (GADA).
Genotype frequencies, measures of insulin secretion, and metabolic traits within LADA differed according to GAD antibody (GADA) quartiles, but even the highest quartile differed from type 1 diabetes.
Of type 2 diabetes-associated genes, the CC/CT genotypes of rs7961581 (TSPAN8) and the obesity-linked AA/AC genotypes of rs8050136 (FTO) were associated with LADA in general, but mainly in low anti-GADLADA patients (P = 0.004 and P = 0.004, respectively).
There is a significant number of patients with latent autoimmune diabetes in adults (LADA) in Japan, and a high level of GAD autoantibodies has a high predictive value for future insulin deficiency in such patients.
The aim of the study was 1) to establish the prevalence of GAD antibodies (GADab) in a population-based study of type 2 diabetes in western Finland, 2) to genetically and phenotypically characterize this subgroup, and 3) to provide a definition for latent autoimmune diabetes in adults (LADA).