During the past few years findings from two studiesthe International Study of Asthma and Allergies in Childhood (ISAAC)¹ and the European Community Respiratory Health Survey (ECRHS)²seem to have dominated much of the thinking about the geographical variations in the prevalence of asthma. These studies suggest important variations by geographical site in different countries and, to a lesser extent, in study centres within countries. However, these studies only raise new questions as to how geographical factors contribute to the aetiology of asthma. For example, are the geographical variations in the prevalence of asthma caused by unique exposures to disease causing agents found only in local environments? Do differences in geographical location in some way alter host susceptibility? Do local environmental conditions, either physical or sociocultural, alter the host/agent interactions in ways that are critical to the expression of this condition?

In this issue of Thorax Duran-Tauleria and Rona³ further . . . [Full text of this article]