Increasing prevalence of specific IgE to aeroallergens in an adult population: two cross-sectional surveys 8 years apart: the Copenhagen Allergy Study

Abstract

Background: There is evidence that the prevalence of respiratory allergy has increased in children in many countries. However, this evidence is largely based on questionnaire data, and little is known about similar trends in adults.

Objective: We investigated whether the prevalence of specific IgE to aeroallergens had increased in an adult general population over an 8-year period.

Methods: Two cross-sectional surveys were carried out in 1990 and 1998. A mailed screening questionnaire on respiratory symptoms sent to random samples of 15- to 41-year-old subjects living in Copenhagen (Denmark) preceded both surveys. Random samples of responders were invited to a health examination, including assessment of specific IgE to 6 common aeroallergens. Totals of 312 (74.6% of the invited subjects) and 482 (53.4% of the invited subjects) subjects were examined in 1990 and 1998, respectively. Analyses of serum samples from both surveys were performed in 1999.

Results: The prevalence of specific IgE to at least one allergen increased significantly from 1990 to 1998 (26.5% vs 33.9%; odds ratio adjusted for sex, age, and season of examination, 1.63; 95% confidence interval, 1.15-2.32; P = .006). This increase remained unexplained after adjustment for changes in questionnaire variables on lifestyle and home environment. The clinical significance of this increase was underlined by a corresponding increase in the prevalence of allergic rhinitis symptoms associated with specific IgE positivity.

Conclusion: We found that the prevalence of specific IgE positivity to aeroallergens increased in an adult Danish general population from 1990 and 1998.