Allergen content in dust from homes and schools in northern Norway in relation to sensitization and allergy symptoms in schoolchildren

Abstract

Previous studies have shown a high prevalence of atopic diseases among school children in the community of Sør-Varanger. Moreover, animal dander followed by pollen and house dust mite, were the most common allergens in skin prick tests. To assess the allergen content in homes (living-rooms and mattresses) and classrooms of children living in an arctic area at 70 degrees. The presence of allergens in homes and schools and their relationship to atopy was of particular interest. Dust samples from 38 homes and seven schools in northern Norway were collected by vacuum cleaning. The presence of allergens of dog, birch, timothy, Cladosporium herbarum, codfish and hen egg-white was investigated by radio-allergosorbent test (RAST) inhibition and the presence of major allergens of cat Felis domesticus (Fel d I) and house dust mites (HDM) Dermatophagoides pteronyssinus (Der p I) and Dermatophagoides farinae (Der f I) by enzyme-linked immunosorbent assay (ELISA). Mattresses contained significantly more dust per unit area than living-rooms and classrooms. No statistically significant differences in allergen content for dog, birch, timothy. Cladosporium, codfish and hen egg-white were seen between HDM-sensitized and non-atopic children. Most dust samples contained dog allergens with the highest allergenic activity found in living-rooms of those keeping dogs. An increased level of Fel d I was detected in only one of 38 samples from living-rooms (this family kept a cat) and in 25 of 38 samples from mattresses with ranges from 24 to 84 ng/m2. The highest concentrations were found in mattresses of children keeping cats. Increased levels (> or = 25 ng/m2) of Der p I were found only in homes and virtually only in mattresses of HDM-sensitized children. An increased level of Der f I was found in only one case, i.e. in the mattress of an HDM-sensitized child where additionally Der p I and HDMs were demonstrated microscopically. When relating Der p I to HDM-sensitization an odds ratio of more than 16 (95% CI: 1.6-394.3) was found. All extracts from living-rooms included codfish allergens. Low RAST inhibition values were detected for hen egg-white. Cladosporium, birch and timothy pollen in most samples. Furthermore, the study demonstrated that dust from schools was relatively free of allergens. Previous findings indicating that the main allergen exposure problem in this geographical area is that of pet allergens were confirmed.