Abstract
Although there is wide variation in the prevalence of nasal allergies internationally, the extent to which this is due to variation in etiological factors is not known. The purpose of the present study was to define the relative importance of atopy and other risk factors for nasal allergies, including hayfever, among young adults in Melbourne. The subjects were participants in the second phase of the European Community Respiratory Health Survey; 876 adults between 20 and 45 years of age completed a detailed respiratory questionnaire, 745 had skin prick testing with common aeroallergens and 675 underwent methacholine challenge. Total and allergen-specific IgE levels were measured in 701 and 693 subjects by radioimmunoassay and RAST, respectively. Nasal allergies, including hayfever, were reported by 47.5% of randomly selected participants. Females, non-smokers, subjects with a family history of allergies, those with current asthma, a history of eczema and nasal symptoms induced by dust, pollen or food were significantly more likely to have nasal allergies. Oral antihistamines had been used by 45.7% of those reporting nasal allergies and 12.4% had received allergen immunotherapy. The risk of nasal allergies, including hayfever, was increased 6.1-fold by atopy, particularly by positive skin tests to outdoor allergens such as Birch, Timothy grass, plantain, olive, Cladosporium and Rye grass pollen. Total serum IgE was significantly higher in subjects reporting nasal allergies than in those who did not report such allergies. There were significant trends in the prevalence of nasal allergies with increasing titers of specific IgE directed against all allergens tested. In conclusion, the significant independent risk factors for nasal allergies, including hayfever, in young adults were atopy, particularly sensitization to Timothy grass, house dust mites and plantain, current asthma, not smoking, a history of eczema and female gender. Future research needs to distinguish between hayfever and perennial allergic rhinitis, which was not possible in the present study.
