Risk factors associated with allergic and non-allergic asthma in adolescents

Authors

  • Christer Janson,

    Corresponding author
    1. Department of Medical Sciences: Respiratory Medicine and Allergology, Uppsala University, Uppsala, Sweden
    2. Asthma and Allergy Research Centre, Uppsala University, Uppsala, Sweden
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  • Pia Kalm-Stephens,

    1. Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
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  • Tony Foucard,

    1. Asthma and Allergy Research Centre, Uppsala University, Uppsala, Sweden
    2. Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
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  • Kjell Alving,

    1. Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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  • S. Lennart Nordvall

    1. Asthma and Allergy Research Centre, Uppsala University, Uppsala, Sweden
    2. Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
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  • Ethics
    The study was approved by the Ethical Committee of the Medical Faculty of Uppsala University

Christer Janson, MD, Department of Medical Sciences: Respiratory Medicine and Allergology, Akademiska sjukhuset, SE 751 85 Uppsala, Sweden.
Tel: +46-186114115
Fax: +46-186112819
email: christer.janson@medsci.uu.se

Abstract

Introduction:  Risk factors for asthma have been investigated in a large number of studies in adults and children, with little progress in the primary and secondary prevention of asthma.

The aim of this investigation was to investigate risk factors associated with allergic and non-allergic asthma in adolescents.

Methods:  In this study, 959 schoolchildren (13–14 years old) answered a questionnaire and performed exhaled nitric oxide (NO) measurements. All children (n = 238) with reported asthma, asthma-related symptoms and/or increased NO levels were invited to a clinical follow-up which included a physician evaluation and skin-prick testing.

Results:  Asthma was diagnosed in 96 adolescents, whereof half had allergic and half non-allergic asthma. Children with both allergic and non-allergic asthma had a significantly higher body mass index (BMI) (20.8 and 20.7 vs. 19.8 kg/m2) (p < 0.05) and a higher prevalence of parental asthma (30% and 32% vs. 16%) (p < 0.05). Early-life infection (otitis and croup) [adjusted odds ratio (OR) (95% confidence interval (CI)): 1.99 (1.02–3.88) and 2.80 (1.44–5.42), respectively], pets during the first year of life [2.17 (1.16–4.04)], window pane condensation [2.45 (1.11–5.40)] and unsatisfactory school cleaning [(2.50 (1.28–4.89)] was associated with non-allergic but not with allergic asthma.

Conclusion:  This study indicates the importance of distinguishing between subtypes of asthma when assessing the effect of different risk factors. While the risk of both allergic and non-allergic asthma increased with increasing BMI, associations between early-life and current environmental exposure were primarily found in relation to non-allergic asthma.

Please cite this paper as: Janson C, Kalm-Stephens P, Foucard T, Alving, K and Nordvall SL. Risk factors associated with allergic and non-allergic asthma in adolescents. The Clinical Respiratory Journal 2007;1:16–22.

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