Phase A of the study will be based on the survey of the general population (1-85 y/o) of two well-defined target areas and recruitment of those with a self-reported physician diagnosis of asthma. Phase B of the study is the retrospective elicitation of the health record of participants. In Phase C of the study builds upon the data of Phase A and B and other published studies to extrapolate the results to the Canadian population for the next 10 years, as such it does not involve direct population sampling.