Are atopy and specific IgE to mites and molds important for adult asthma?

Background: Atopy is known to be important for childhood asthma, but this is to our knowledge the first study on its relation with development of asthma in adulthood. Objectives: We addressed the role of atopy, measured as total IgE and Phadiatop, and of specific IgE antibodies to mites and molds in development of adult-onset asthma. Methods: A population-based incident case-control study was conducted in the Pirkanmaa District in Southern Finland. All new clinically diagnosed cases of asthma 21-63 years of age were recruited 1997-2000 in the study district. A random sample of the source population formed the controls. A total of 485 cases and 665 controls provided a serum sample. Diagnosis of asthma was based on demonstration of reversibility in lung function investigations. Subjects with previous asthma were excluded. Phadiatop score and IgE antibodies were analyzed with the UniCAP system. Results: The adjusted odds ratio of asthma increased with total IgE and Phadiatop score in a dose-dependent pattern. IgE antibodies to house dust mite and storage mite were significantly related to an increased risk of asthma. Among molds,, increased risk of asthma was seen in relation to IgE antibodies to Aspergillus fumigatus and Cladosporium herbarum. Population attributable fraction due to sensitization to common aeroallergens was 30% (95% CI, 23-41). Conclusion: Atopy is a strong determinant of asthma in adulthood. Specific IgE antibodies to mites and some molds are significantly related to increased risk of adult-onset asthma. A considerable fraction of adult asthma could be prevented by measures to reduce atopy.