accelerated progression from islet autoimmunity to diabetes is causing the escalating incidence of type 1 diabetes in young children the incidence of type 1 diabetes is rising worldwide particularly in young children since type 1 diabetes is preceded by autoimmunity to islet antigens there must be a consequent increase in the incidence of islet autoimmunity in young children or a more rapid rate of progression to diabetes once islet autoimmunity initiates this study was to determine whether the incidence of islet autoimmunity or the rate of progression from autoimmunity to diabetes onset has changed over a 20year period in children genetically predisposed to type 1 diabetes between 1989 and 2010 children who were firstdegree relatives of patients with type 1 diabetes and who were born in germany were prospectively followed from birth without intervention a total of 324 children babydiab study born between 1989 and 2000 and 216 children teddy study born between 2004 and 2010 with matched hla genotypes were recruited before age 3 months and included for analysis children were followed for the development of autoantibodies to insulin gad and ia2 and for progression to diabetes the cumulative frequency of diabetes by age 4 years was 25 95 ci 0842 in babydiab children and 62 95 ci 23101 in teddy children p 003 the cumulative frequency of islet autoantibodies by age 4 years was similar in the children from both studies 113 vs 139 progression to diabetes from the development of islet autoantibodies was markedly increased in autoantibodypositive children from the more recently recruited teddy cohort 50 progression within 852 months for babydiab children vs 96 months for teddy children p 0009 also if children were further selected on the basis of highrisk hla genotypes or the development of autoantibodies to multiple islet antigens p 001 the findings suggest that recent increasing incidence of type 1 diabetes in young children could be due to weakening of mechanisms that normally regulate autoimmune destruction of islet beta cells