Grant: Operating Grant

Why some children develop asthma, and others do not, remains uncertain. Genetics play a role, as a family history of allergy and asthma increases the risk. However many children with a family history do not develop asthma, while many children with asthma have no family history. A leading theory is that allergy and asthma result from the combined influences of genes and the environment. Allergy is very important in determining whether childhood asthma continues into adult life, and how severe it is. Some environmental exposures in early life increase the risk of allergy, but other exposures appear to be protective. The balance between protective and harmful environmental exposures, and their timing and intensity, may change the way that genes affect the likelihood of getting asthma. Exploring this idea is the main goal of this research project. A Genetic Risk Score (GRS) for asthma has recently been developed; the higher an individual's score, the more likely is life-long asthma, but how environmental exposures influence this genetic risk is not known. We will use an existing Canadian birth cohort which is following over 3,300 infants (the CHILD Study) to explore how selected environmental factors affect allergies and asthma in children with different Genetic Risk Scores. The CHILD Study has information about environment from pregnancy through childhood, and has conducted home inspections collecting house dust for measurements including allergens and mold. We also have information on outdoor air exposures, detailed dietary information for mother and baby, and many blood, urine, and nasal samples. We will study whether selected exposures increase or decrease the risk of development of allergies and asthma, to determine why children at different levels of genetic risk develop these conditions while others do not. Our ultimate goal is to identify strategies which will reduce the number of children who go on to develop life-long respiratory disorders.