Worth the wait: type 1 diabetes prospective birth cohort studies enter adolescence.

Autoantibodies to islet cell proteins currently provide the only reliable indication that the process leading to type 1 diabetes has started. The period from the first detection of islet autoantibodies to clinical onset of diabetes can last months or years. Longitudinal birth cohort family studies give crucial information concerning the natural history of islet autoimmunity and have already shown that islet autoantibodies, which precede diabetes development, often appear in early infancy. In this issue of Diabetologia, Ziegler et al (DOI: 10.1007/s00125-012-2472-x ) and Parikka et al (DOI: 10.1007/s00125-012-2523-3 ) report findings from their birth cohort studies after numerous children have entered adolescence, allowing a more complete picture of islet autoimmunity in childhood to be revealed. Both groups are in accord that, between 6 months and 3 years of age, there is an explosion of islet autoimmunity in susceptible children and that the great majority (approximately 80%) of genetically at-risk children who present with diabetes before adolescence develop islet autoimmunity at this young age. These findings emphasise the importance of early life events in disease pathogenesis and have major implications for efforts aimed at preventing type 1 diabetes.