Background: Although clinical and experimental studies suggest that upper respiratory tract dysfunction may affect the lower airways, rhinitis is usually not studied as a potential risk factor for asthma. This is because both diseases share key elements of pathogenesis and are usually considered as different manifestations of the same underlying "atopic" state.
Objective: We sought to assess whether asthma is associated with rhinitis in the absence of immunologic disorders in a population study.
Methods: Data from 34 centers participating in the European Community Respiratory Health Survey were analyzed. Random samples of 20- to 44-year-old subjects were invited to complete a detailed questionnaire and undergo total and specific IgE measurements, skin prick tests to 9 allergens, and bronchoprovocation challenges with methacholine.
Results: Subjects with perennial rhinitis (n = 1412) were more likely than control subjects (n = 5198) to have current asthma. After adjustment for sex, age, smoking habit, family history of asthma, geographic area, and season at the time of examination, asthma was strongly associated with rhinitis among atopic subjects (odds ratio [OR] = 8.1; 95% confidence interval [CI] = 5.4-12.1) but also among nonatopic subjects (OR = 11.6; 95% CI = 6.2-21.9). Moreover, the association remained very strong when the analysis was restricted to nonatopic subjects with IgE levels of 80 kIU/L or less (OR = 13.3; 95% CI = 6. 7-26.5). In nonasthmatic subjects bronchial hyperresponsiveness was also more frequent in subjects with rhinitis than in those without rhinitis (OR = 1.7; 95%CI = 1.2-2.6 in nonatopic subjects with IgE levels of </=80 kIU/L).
Conclusion: The strong association between perennial rhinitis and asthma in nonatopic subjects with normal IgE levels is consistent with the hypothesis that rhinitis is an independent risk factor for asthma.