Atopy in Norwegian and Russian adults: a population-based study from the common border area

Background: Several studies have concluded that atopy is more common in Western than in Eastern Europe. We aimed to study whether a similar difference exists between Norwegian and Russian adults living in geographically adjacent areas. Methods: A cross-sectional population-based study was performed in Sor- Varanger municipality (Norway) and in the cities of Nikel and Zapolyarny (Russia). The Russian cities are heavily polluted by sulfur dioxide from local nickel industry. In addition to questionnaire information, results on IgE sensitization (S-Phadiatop, Pharmacia & Upjohn, Uppsala, Sweden) were obtained from 3134 Norwegian and 709 Russian participants. Results: A positive Phadiatop was found in 20.7% of the Norwegians (men 21.9%, women 19.7%) and in 27.5% of the Russians (men 35.7%, women 23.0%); the sex- and age-adjusted relative risk of testing positive in Russia being 1.49 (95% CI 1.23-1.81). The Norwegian participants reported more atopic dermatitis and hay fever, although this difference was statistically significant only for atopic dermatitis in women. Conclusion: IgE sensitization was more common in Russia than in Norway, unlike findings from other east-west European studies. The Russians did not, however, report more atopic diseases. This discrepancy might reflect different awareness of allergies in the two countries and demonstrates the need for objective markers of atopy when comparing prevalence in different populations.