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).
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).
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).
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.
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.
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.
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).