Environmental determinants associated with Type 1 diabetes-related autoantibodies in children

Abstract: Background Type 1 diabetes is a severe disease, which affects children with potentially severe consequences. The global incidence of Type 1 diabetes is increasing rapidly especially in young children. Second to Finland, Sweden has the highest incidence of Type 1 diabetes in the world.The rapidly increasing incidence cannot be explained by a possible variability of the presence of risk genes in the population, but rather environmental factors.Therefore, environmental factors contributing to ß-cell auto immunity should be of importance for the process leading up to clinical Type I diabetes in genetically predisposed individuals. Those factors should preferably be revealed early in life. The aim of this thesis was to investigate a large population of Swedish children in order to identify environmental factors, which could contribute to the autoimmune reaction towards insulin-producing ß-cells.Material and methodsFamilies from the prospective population-based ABIS-project (All Babies in southeast Sweden) were studied. Blood samples from children were analysed at birth, one year and 2½ years of age for diabetes-related autoantibodies towards Tyrosine phosphatase (IA-2A) and Glutamic Acid Decarboxylase (GAD). The parents completed questionnaires at birth, one year and 2½ years of age.Results Short breast-feeding period, early exposure to cow's milk formula and late introduction of gluten-containing foods as well as large consumption of cow's milk at the age of one year were all risk determinants for development of autoantibodies at 2½ years of age. Combined early introduction of cow's milk formula and late introduction of gluten-containing food increased the risk six times for acquiring persistent autoantibodies at 2½ years of age. Parenting stress and experiences of serious life events were associated with the induction of diabetes-related autoimmunity. Infections during pregnancy are related to diabetes-related autoantibodies in cord blood and at the age of one year.Allergic symptoms such as rash, wheezing, allergy against fur-bearing animals and food allergies implied a risk for development of diabetes-related autoantibodies. Autoantibodies in cord blood had disappeared at the age of one year, and can therefore not be used as a screening method to predict diabetes in the general population.ConclusionsNone of the examined risk factors alone can explain Type 1 diabetes-related autoimmunity; but early nutrition, parental stress and infections can contribute to the development of diabetes-related autoantibodies.Autoantibodies in cord blood cannot be used to predict later diabetes-related autoimmunity. Different aberrances in the immune system seem to co-exist in certain individuals.