Identification of risk factors, including lifestyle and environmental exposures, for asthma and allergies in children in five European countries
The project aimed to confirm the protective effect against asthma and atopy found in cross-sectional studies for children growing up on a farm compared to their peers also living in rural areas, but not on a farm. Furthermore, the aim of the project was to further determinate the single environmental factors that contribute to this protective effect. The study modules included questionnaires, a clinical visit of the children at age 1 year, blood analyses (cytokine measurements, specific serum IgE, genotyping, assessment of gene expression) and analysis of environmental samples (home dust, cow's milk). Fieldwork has been completed in five European countries. The study has provided an extensive data set on the variation in the prevalence of atopic disease between farm children and non-farm children, which is unique in the world. It identified new insights into the role of many determinants, e.g. lifestyle and genetic factors, and offers huge potential for further epidemiological analyses. The project confirmed the protective farm effect seen in previous cross-sectional studies also in the PASTURE birth cohort, as the parents and siblings prevalence rates were significantly lower among farming families than non-farming controls. Furthermore, we did find differences in INF-gamma and TNF-alpha secretion between farm and non-farm children at birth. Both cytokine levels were increased after stimulation with PMA / Ionomycin among the farm children. When investigating the factors underlying this 'farm effect', we could demonstrate that maternal exposure to farm animals and exposure to barns was responsible for the difference in cytokine levels in cord blood between farm and non-farm children. In addition, cord blood IgE antibodies to outdoor allergens, in particular to grass pollen, were more prevalent among non-farmers than among farmers, while farm children had a higher prevalence of IgE antibodies to food allergens than non-farm children.
Identification of genetic polymorphisms associated with asthma and allergies in children in five European countries
The project aimed to identify gene polymorphisms involved in the development of asthma and atopic disease, as well as to investigate gene expression and gene-environment interactions. Genotyping could be performed in a large number of children, and material for genotyping of their parents could also be obtained. The project offers huge potential for further epidemiological analyses.