Pollution and the development of allergy: the East and West Germany story.

Allergic diseases are partly genetically determined, but environmental factors have a strong influence on the expression of allergic symptoms in genetically predisposed subjects. In particular, outdoor air pollution has received widespread attention as a potential manifestation factor. The unification of Germany provided a unique opportunity to study the impact of radically different environmental and social conditions on the development of allergies in two genetically homogeneous populations. A high car density and NO2 exposure were typical for many West German cities. Severe pollution due to heavy industrialization and private coal burning for heating purposes were the main sources of air pollution in East German cities. We assessed the prevalence of asthma and allergic disorders in 9-11 year old children in in East Germany (Leipzig and Halle) and in West Germany (Munich). All fourth grade pupils in Munich (n = 7,445) were compared with those in Leipzig and Halle 1991 (n = 3,105). Hay fever, skin test reactivity to common aeroallergens and asthma were considerably more prevalent in West Germany as compared to East Germany. When atopy was taken into account, there was no longer a significant difference in the prevalence of asthma between the two parts of the country.