Allergens in house-dust samples in Germany: results of an East-West German comparison

The background of this study is the finding of several studies that the frequency of respiratory allergies was significantly higher in the former West Germany than the former East Germany. The present study investigated the levels of allergens of house-dust mite (Der p 1 and Der f 1), cat (Fel d 1), and cockroach (Bla g 2) in the household dust of 201 homes in Hamburg (West Germany) and 204 homes in Erfurt (East Germany), and examined the factors that affect these levels. The characteristics of homes were assessed by a questionnaire. The allergen levels were studied in dust from living rooms (LR), bedrooms (BR), and mattresses (MA). We detected in samples from Hamburg significantly higher allergen concentrations than in Erfurt: three times higher Der p 1, five times higher Der f 1, and three times higher Fel d 1. For Bla g 2, no comparison was possible because the concentrations were below the detection limit in 93% of the samples. Most of the differences could be explained by differences in housing and living characteristics between both cities. The mean ratio of Der p 1 levels in mattress dust between Hamburg and Erfurt decreased from 4.1 to 1.54 (NS) after adjustment for season, building material, age of the house, story of the dwelling, type of heating, age of carpet/mattress, presence of dogs, and indoor climate (temperature, humidity). The mean ratio of Der f 1 levels decreased from 6.9 to 2.78 (P<0.05) after adjustment for these factors. The mean ratio for Fel d 1 in mattress dust decreased fom 4.03 to 1.65 (P<0.05) after adjustment for season, building material, story of dwelling, size of dwelling, ventilation, cleaning routines, and pets. A similar reduction was seen for floor dust (LR plus BR). Our results indicate that the differences between the concentrations of mite and cat allergens found in Hamburg and Erfurt are explicable mainly, but not completely, by different building characteristics (age of houses, building material, story, and size of the dwelling) which affected the indoor climate, as well as by differences in other individual living habits (keeping of pets, age of carpets or mattresses, and cleaning routines).