Epidemiology of pollution-induced airway disease in Scandinavia and Eastern Europe.

Several potential environmental factors, particularly air pollutants, have been implicated as causal factors for the increased prevalence of allergic disease in western industrialized countries. However, even when combined, these factors can only partly explain the increase. Differences in prevalence of allergy are apparent between urban and rural areas of industrialized countries, with positive skin prick tests being more common in children living in urban regions. However, the prevalence of atopy is lower in children in central and Eastern Europe, where air pollution poses a major problem, than in Western Europe. Indeed, preliminary data from the International Study of Asthma and Allergy in Children (ISAAC) confirm that the prevalence of childhood atopy is lower in Eastern Europe than in Scandinavia. Although air pollution is undoubtedly associated with the development of allergic disease, other factors connected with western lifestyle, such as changes in diet and living conditions, may play an important role and provide a possible explanation for the higher prevalence of allergic disease in western industrialized countries.