Figure 1. Proposed conceptual model for how T1D develops and the stages of T1D progression. This figure emphasises how the loss or dysfunction of β-cells leads to T1D. It is designed to demonstrate that T1D develops through several phases, often beginning long before a formal diagnosis. The original Eisenbarth model (1984) represents the natural development of type 1 diabetes. Adapted from: Di Meglio et al., Type 1 diabetes, The Lancet 2018 1.