An increased understanding of the causes of asthma is coming from the international
comparisons of asthma prevalence, particularly those from the European Community
Respiratory Health Survey of asthma prevalence in adults and the International Study of
Asthma and Allergies in Childhood. From these and other studies of asthma prevalence, it is
possible to draw some tentative conclusions as to the patterns of asthma prevalence
worldwide. There are five striking patterns: first, asthma prevalence is increasing worldwide; …