ENDIA is a unique prospective study of putative environmental triggers of T1D in first degree relatives followed from the second trimester of pregnancy. The incidence of T1D has increased progressively in the last 50 years. The genotype pattern has changed somewhat in that the high risk patterns are seen in the younger children presenting with T1D whilst lower risk patterns now are prevalent in the older onset group. Thus there is an interaction with genotypic risk profile and the environment, which is evolving. The changes in incidence seem to link to environmental changes that mirror the modern western lifestyle. The various human microbiomes interact with the immune system and metabolism. The current pro-inflammatory environment is changing these microbiomes and appears to be contributing to the rapid rise of non-communicable disease. In ENDIA the children presenting with T1D are <18 y and 80% of these children will already have had detectable islet autoantibodies by 3 years of age. Analysis of cord blood in high-risk genotype subjects predicts which children will progress to the onset of T1D. Thus the origins of T1D have developed prior to the age of 3y and this points to the presence of triggers occurring during pregnancy and early life. The ENDIA project is examining changes in the microbiome of the mother that links to development of T1D autoimmunity in an at risk population.