THE ENVIRONMENT AND ATOPY

• A landmark study that identified that the prevalence of atopy is altered by the environment.

von Mutius, E et al. Prevalence of asthma and atopy in two areas of West and East Germany. Am. J. Respir. Crit. Care Med. 149, 358-364 (1994)

• Prior to the fall of the Berlin Wall in Germany, there was a 3-fold difference in the prevalence of atopy between the two different states. Considering that genetic differences were stable overtime, as most of the inhabitants of these two regions were of German descent, reunification of these two regions produced great changes. Differences in the prevalence of asthma in children between cities in former East Germany (Leipzig and Halle) and West Germany (Munich) after reunification was wholly accounted for by the 2.5-fold greater prevalence of atopy in Munich, in the migrated families from the East.

• Changes in prevalence of this magnitude cannot be explained by genetics, but point to environmental determinants of atopy. What these are, we still do not know.                                                                                     
        Taylor AJN. ABC’s of allergies. BMJ 316, 997-999 (1998)