Early and late C‐peptide responses during oral glucose tolerance testing are oppositely predictive of type 1 diabetes in autoantibody‐positive individuals

We examined whether the timing of the C‐peptide response during an oral glucose tolerance test (OGTT) in relatives of patients with type 1 diabetes (T1D) is predictive of disease onset. We examined baseline 2‐h OGTTs from 670 relatives participating in the Diabetes Prevention Trial‐Type 1 (age: 13.8 ± 9.6 years; body mass index z‐score: 0.3 ± 1.1; 56% male) using univariate regression models. T1D risk increased with lower early C‐peptide...