The accelerator hypothesis and increasing incidence of type 1 diabetes.

To summarize the relevance of the 'accelerator hypothesis' to type 1 diabetes pathogenesis and examine if recent evidence supports the hypothesis. The 'accelerator hypothesis' proposes 'three processes in type 1 diabetes which variably accelerate the loss of beta cells through apoptosis: constitution, insulin resistance and autoimmunity'. Insulin resistance is an independent risk factor for progression to clinical type 1 diabetes in people with islet autoimmunity. Higher bodyweight is also associated with type 1 diabetes development although no longitudinal studies have simultaneously assessed bodyweight and insulin resistance in preclinical diabetes. Currently, there is no evidence for the view that accelerated beta-cell apoptosis is due to insulin resistance in the pathogenesis of type 1 diabetes. Insulin resistance accelerates development of type 1 diabetes in people with islet autoimmunity and insulin deficiency. The increasingly 'obesogenic' environment which promotes insulin resistance could account for the rising incidence of type 1 diabetes.