Environmental Triggers of Type 1 Diabetes: The MIDIA Study (MIDIA is the Norwegian acronym for "Environmental Triggers of Type 1 Diabetes")

Type 1 diabetes is one of the most prevalent chronic diseases in childhood, and is the end-stage of a destructive inflammation of the insulin producing beta-cells in the pancreas. The disease is caused by unknown environmental factors affecting individu als at genetic risk. In contrast to other complex diseases, the major genes associated with type 1 diabetes are known. Norway is a high-risk country, and the incidence has increased three folds during the past three decades. Selection bias, small sample s ize, and absence of biologic markers of exposure compromise retrospective studies exploring associations between environmental factors and type 1 diabetes. This prospective study will employ a population based cohort of 100,000 in which type 1 diabetes hi gh-risk children are ascertained by identification of the HLA-DRB1*0401-DQA1*0301-DQB1*0302/ DRB1*0301-DQA1*0501-DQB1*0201 genotype. Such new-borns have an estimated 17% lifetime risk for getting the disease. This is the case for 2.7% of the 60,000 babies born in Norway each year. 2,700 children will be followed-up for 15 years with stool samples, questionnaires and capillary blood samples. The MIDIA study is internationally unique since data are available from pregnancy via the Norwegian Mother and Child Cohort Study. Advanced genomics are applied to detect candidate viral triggers of autoimmunity and regulators of progression towards overt type 1 diabetes, and biomarkers will be used to study dietary and other environmental exposures. The aim of MIDIA i s to identify the environmental factor(s) causing type 1 diabetes and to study the interplay between genetic and environmental regulators to identify targets for prevention. We here apply for funding to establish the high-risk cohort and for follow-up o f the children. One research fellow is already funded from the Norwegian Research Council to study enterovirus in MIDIA. Three new applications for research fellows using data from MIDIA are submitted this year.