GAD65 autoantibodies and glucose tolerance in offspring born to women with and without type 1 diabetes (The EPICOM study)

The aims of this study were to examine presence of GAD65 autoantibodies (GAD65aab) in offspring born to women with type 1 diabetes (T1D) and controls and if more were GAD65aab‐positive if diagnosed with diabetes or pre‐diabetes. This EPICOM study is a prospective follow‐up study focussing on pregnancies complicated by maternal T1D. The EPICOM study includes offspring (n = 278) born to mothers with pre‐gestational T1D between 1993 and 1999 and matched un‐exposed controls (n = 303). Age at the time of follow‐up was 16.7 years (13.0–20.4 years). GAD65aab was measured using the Glutamic Acid Decarboxylase Autoantibody RIA kit from RSR(©). An Oral Glucose Tolerance Test (OGTT) was performed, and abnormal glucose tolerance was defined as having either diabetes, impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). GAD65aab could be measured in 561 participants. Of these, 17 (3%) were positive for GAD65aab (≥25 U/ml) with 11 (4%) offspring being born to women with T1D and 6 (2%) controls. The difference in GAD65aab status was not statistically significant (p = .2). One was diagnosed with GAD65aab‐negative diabetes during the study, 18 were diagnosed with IFG, and 44 with IGT. Overall, more were GAD65aab‐positive if diagnosed with abnormal glucose tolerance (p = .03). We found no association between GAD65aab status and HOMA‐IR, HOMA‐IS, birthweight, mode of delivery or maternal BMI prior to pregnancy. Our study found no overall difference in GAD65 status between offspring born to women with T1D and their matched controls. However, among the participants diagnosed with pre‐diabetes more were GAD65‐positive.