Type 1 diabetes: prospective cohort studies for identification of the environmental trigger.

Type 1 diabetes (T1D) is one of the most common chronic diseases with childhood onset, and the disease incidence has increased two to fivefold over the past half century by as yet unknown means. T1D occurs when the body's immune system turns against itself, destroying in a very specific and targeted way-the pancreatic β-cells. T1D results from poorly defined interactions between susceptibility genes and environmental determinants. In contrast to the rapid progress in finding T1D genes, identification and confirmation of environmental determinants remain a formidable challenge. This review article will give an overview of ongoing prospective cohort studies aiming to identify the environmental trigger(s) causing T1D.