Environmental and occupational respiratory disorders
Are atopy and specific IgE to mites and molds important for adult asthma?

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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.

Section snippets

Study design

This study was a population-based case-control study of incident asthma cases. The source population consisted of adults 21 to 63 years of age living in the Pirkanmaa District, which is a geographically defined area in South Finland, with a population of 440,913 in 1997.9, 10, 13, 14 This study was approved by the ethics committees of the Finnish Institute of Occupational Health and the Tampere University Hospital.

Definition and selection of cases

We recruited systematically all new cases of asthma diagnosed clinically in the

Incidence of adult-onset asthma and characteristics and IgE antibodies of cases and controls

The prevalence of asthma (previous and current) in this working-age population was 7.5%. The incidence of adult-onset asthma during our study period was 0.90 per 1000 person-years. Table II presents the characteristics of cases and controls. Cases had higher levels of total IgE and higher Phadiatop scores than controls (Table III). Cases had also more frequently positive IgE antibodies to mites and molds compared with controls (Table IV).

Atopy and the risk of asthma

The risk of incident asthma increased in a dose-dependent

Discussion

To our knowledge, this study includes the largest number of asthma cases among all studies addressing the determinants of clinically verified adult-onset asthma published to date. The incident case-control study design is very efficient compared with a cohort study, which would yield a similar amount of information. With our asthma incidence rate of 0.9 cases per 1000 person-years, the current study corresponded to a follow-up of approximately 100,000 adults for 5.8 years (the denominator was

Conclusion

This large population-based study of incident asthma provides evidence that atopy, measured as total IgE and specific IgE antibodies to common aeroallergens, is a strong determinant of new-onset asthma in adulthood. In addition, specific IgE antibodies to mites Dermatophagoides pteronyssinus and Acarus siro significantly increase the risk of adult-onset asthma. IgE antibodies to 6 molds, especially Aspergillus fumigatus and Cladosporium herbarum, were also related to the development of asthma

References (31)

  • C.F. Robertson et al.

    Asthma prevalence in Melbourne schoolchildren: have reached the peak?

    Med J Aust

    (2004)
  • P.G. Holt

    Key factors in the development of asthma: atopy

    Am J Respir Crit Care Med

    (2000)
  • J.B. Soriano et al.

    Risk of asthma in the general Spanish population attributable to specific immunoresponse

    Int J Epidemiol

    (1999)
  • M.S. Jaakkola et al.

    Indoor dampness and molds and development of adult-onset asthma: a population-based incident case-control study

    Environ Health Perspect

    (2002)
  • M.S. Jaakkola et al.

    Immunoglobulin G antibodies against indoor dampness-related microbes and adult-onset asthma: a population-based incident case-control study

    Clin Exp Immunol

    (2002)

    • Cited by (0)

    The data collection of this study was funded by the Ministry of Social Affairs and Health of Finland and the Finnish Work Environment Fund. The data analyses and writing of the manuscript were performed at the University of Birmingham and received funding from the West Midlands Regional Levy Board. The reagents for the specific IgE antibody analyses were purchased at a reduced price from Pharmacia Diagnostics, Sweden (the Finnish branch).

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    Copyright © 2006 American Academy of Allergy, Asthma and Immunology. Published by Mosby, Inc. All rights reserved.