Type 1 diabetes (T1D) is one of the most common chronic diseases in childhood caused by autoimmune-mediated destruction of the insulin-producing pancreatic islet ß-cells. Prospective birth cohort studies contributed to the identification of genetic and environmental factors involved in the pathogenesis of type 1 diabetes. The development and validation of a genetic risk score enabled risk prediction for later development of type 1 diabetes. Consistent findings from prospective studies point to the contribution of intrauterine maternal type 1 diabetes exposure, early childhood viral infections, early childhood growth/obesity, and gut microbiome/dysbiosis in the pathogenesis of type 1 diabetes. Launched in late 2017, the Global Platform for the Prevention of Autoimmune Diabetes (GPPAD) was designed to carry out newborn screening in the general population, identify infants at high genetic risk of developing type 1 diabetes, and offer them participation in trials to prevent disease initiation.