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Asthma during the primary school ages – prevalence, remission and the impact of allergic sensitization

Authors

  • A. B. Bäcklund,

    1. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden
    2. Department of Respiratory Medicine and Allergy, University of Umeå, Umeå, Sweden
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  • M. S. Perzanowski,

    1. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden
    2. Department of Environmental Health Science, Columbia University, New York, NY, USA
    3. Asthma and Allergic Diseases Center, University of Virginia, Charlottesville, VA, USA
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  • T. Platts-Mills,

    1. Asthma and Allergic Diseases Center, University of Virginia, Charlottesville, VA, USA
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  • T. Sandström,

    1. Department of Respiratory Medicine and Allergy, University of Umeå, Umeå, Sweden
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  • B. Lundbäck,

    1. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden
    2. Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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  • E. Rönmark

    1. The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden
    2. Lung and Allergy Research, National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Errata

This article is corrected by:

  1. Errata: Corrigenda Volume 62, Issue 8, 968, Article first published online: August 2007

Dr Eva Rönmark
Lung and Allergy Research
National Institute of Environmental Medicine
Karolinska Institutet
SE 171 77 Stockholm
Sweden

Abstract

Background:  Childhood is the most important time for asthma development. The aims of this study were to study changes in prevalence of asthma and wheeze, remission of asthma and changes in risk factor pattern from age 7–8 to age 11–12 in a cohort of school children.

Methods:  In 1996, 3525 children aged 7–8 years in northern Sweden were invited to participate in a parental expanded ISAAC questionnaire survey. The cohort has been followed prospectively with yearly follow-ups to age 11–12, with a 97% yearly response rate. Skin prick tests were conducted at age 7–8 and 11–12.

Results:  The prevalence of physician-diagnosed asthma increased from 5.7% at age 7–8 to 7.7% at age 11–12. Life-time prevalence of wheeze was 34.7% at age 11–12. The remission of asthma was 10% yearly and inversely related to allergic sensitization. Relapses were common, and remission persisting throughout the observation period was 5% yearly. Allergic sensitization was associated with current asthma at age 7–8 [adjusted odds ratio (OR) 4.9 (95% confidence interval (CI) 3.3–7.3)] and when the children were 4 years older [OR 5.6 (3.9–8.2)]. A family history of asthma was associated with current asthma at age 7–8 [OR 3.0 (2.1–4.5)] and 11–12 (OR 2.8 [2.0–3.9]). Ever having lived with a cat was significantly negatively associated with current asthma.

Conclusions:  The prevalence of asthma increased continuously during the primary school ages. Among several significant risk factors, allergic sensitization and a family history of asthma were the most important. With increasing age many known risk factors lost significance. Remission was inversely related to allergic sensitization.

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