Preliminary data indicate that there is a strong association between the incidence of immune-mediated diseases and improving standard of living and hygiene. One of the steepest gradients in standard of living worldwide is present at the border between Russian Karelia and Finland with a sevenfold difference in the gross national product, while Estonia represents a country in rapid transition. These three populations comprise a “living laboratory” providing a unique possibility to test the hygiene hypothesis and gene-environmental interactions in the development of immune-mediated diseases. According to the hygiene hypothesis there is an association between the increased incidence and prevalence of immune-mediated diseases and decreased exposure to the pathogens. The increased incidence of allergy and asthma in developed countries was initially explained by the hygiene hypothesis, but nowadays the increased incidence of autoimmune diseases, such as type 1 diabetes (T1D) is also explained by this hypothesis.
The incidence of T1D is six times lower in Russian Karelia than in Finland, whereas there are very limited differences in the frequency of predisposing and protective HLA ( human leukocyte antigen) genotypes in the background population.
The aim of the DIABIMMUNE project is to assess the role of the hygiene hypothesis in the development of immune-mediated diseases, T1D in particular, and to define the mechanisms behind the potential protective effect conferred by microbial agents. The study design comprises two cohorts: a birth cohort and a cohort comprising young children. The objective is to study 2000 children at the age of 3 and 5 years and to observe 320 newborn infants with increased genetic risk for autoimmune disease from birth up to the age of 3 years. The estimated number of study subjects will altogether be approximately 7000 with Finland, Russian Karelia and Estonia each contributing have 2320 subjects. The children are tested for organ-specific autoantibodies, allergies, infections, gut microflora, and for nutritional factors. The recruitment for the birth cohort starts in September 2008. The project is funded by the European Commission (7 th Framework Programme, project 202063).
Flow sheet for the birth cohorts in the DIABIMMUNE study.
Flow sheet for the cohorts of young children in the DIABIMMUNE study.