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Population based study of risk factors for underdiagnosis of asthma in adolescence: Odense schoolchild studyCommentary: Risk factors for underdiagnosis of asthma in adolescenceCommentary: Identifying the correct risks in diagnosisCommentary: Improving the diagnostic rate in asthma: a community issue

BMJ 1998; 316 doi: https://doi.org/10.1136/bmj.316.7132.651 (Published 28 February 1998) Cite this as: BMJ 1998;316:651

Abstract

Objective: To describe factors related to underdiagnosis of asthma in adolescence.

Design: Subgroup analysis in a population based cohort study.

Setting: Odense municipality, Denmark.

Subjects: 495 schoolchildren aged 12 to 15 years were selected from a cohort of 1369 children investigated 3 years earlier. Selection was done by randomisation (n=292) and by a history indicating allergy or asthma-like symptoms in subject or family (n=203).

Main outcome measures: Undiagnosed asthma defined as coexistence of asthma-like symptoms and one or more obstructive airway abnormalities (low ratio of forced expiratory volume in 1 second to forced vital capacity, hyperresponsiveness to methacholine or exercise, or peak flow hypervariability) in the absence of physician diagnosed asthma. Risk factors (odds ratios) for underdiagnosis.

Results: Undiagnosed asthma comprised about one third of all asthma identified. Underdiagnosis was independently associated with low physical activity, high body mass, serious family problems, passive smoking, and the absence of rhinitis. Girls were overrepresented among undiagnosed patients with asthma (69%) and underrepresented among diagnosed patients (33%). Among the risk factors identified, low physical activity and problems in the family were independently associated with female sex. The major symptom among those undiagnosed was cough (58%), whereas wheezing (35%) or breathing trouble (50%) was reported less frequently than among those diagnosed. Less than one third of those undiagnosed had reported their symptoms to a doctor.

Conclusions: Asthma, as defined by combined symptoms and test criteria, was seriously underdiagnosed among adolescents. Underdiagnosis was most prevalent among girls and was associated with a low tendency to report symptoms and with several independent risk factors that may help identification of previously undiagnosed asthmatic patients.

Key messages

  • One third of young people with asthma are not diagnosed; most are girls

  • Undiagnosed asthma is associated with low physical activity, high body mass index, serious family problems, passive smoking, and the absence of symptoms of rhinitis

  • Cough is the most common symptom among those with undiagnosed asthma

  • Two thirds of those with undiagnosed asthma do not report their symptoms to a doctor, suggesting a need for targeted asthma campaigns

Footnotes

    • Accepted 2 October 1997

    Population based study of risk factors for underdiagnosis of asthma in adolescence: Odense schoolchild study

    1. Hans C Siersted, senior registrar (hc.siersted{at}winsloew.ou.dk)a,
    2. Jesper Boldsen, senior lecturerc,
    3. Henrik S Hansen, senior registrarb,
    4. Gert Mostgaard, registrara,
    5. Niels Hyldebrandt, specialist in allergy and internal medicined
    1. a Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark
    2. b Department of Cardiology, Odense University Hospital
    3. c Centre for Health and Social Policy, Odense University, DK-5230 Odense M
    4. d Private Specialist Clinic, Nørregade 16, DK-5000 Odense C
    5. United Medical and Dental Schools of Guy's and St Thomas's Hospitals, London SE1 9RT
    6. London School of Hygiene and Tropical Medicine, London WC1
    7. Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark
    1. Correspondence to: Dr Siersted
    • Accepted 2 October 1997

    Abstract

    Objective: To describe factors related to underdiagnosis of asthma in adolescence.

    Design: Subgroup analysis in a population based cohort study.

    Setting: Odense municipality, Denmark.

    Subjects: 495 schoolchildren aged 12 to 15 years were selected from a cohort of 1369 children investigated 3 years earlier. Selection was done by randomisation (n=292) and by a history indicating allergy or asthma-like symptoms in subject or family (n=203).

    Main outcome measures: Undiagnosed asthma defined as coexistence of asthma-like symptoms and one or more obstructive airway abnormalities (low ratio of forced expiratory volume in 1 second to forced vital capacity, hyperresponsiveness to methacholine or exercise, or peak flow hypervariability) in the absence of physician diagnosed asthma. Risk factors (odds ratios) for underdiagnosis.

    Results: Undiagnosed asthma comprised about one third of all asthma identified. Underdiagnosis was independently associated with low physical activity, high body mass, serious family problems, passive smoking, and the absence of rhinitis. Girls were overrepresented among undiagnosed patients with asthma (69%) and underrepresented among diagnosed patients (33%). Among the risk factors identified, low physical activity and problems in the family were independently associated with female sex. The major symptom among those undiagnosed was cough (58%), whereas wheezing (35%) or breathing trouble (50%) was reported less frequently than among those diagnosed. Less than one third of those undiagnosed had reported their symptoms to a doctor.

    Conclusions: Asthma, as defined by combined symptoms and test criteria, was seriously underdiagnosed among adolescents. Underdiagnosis was most prevalent among girls and was associated with a low tendency to report symptoms and with several independent risk factors that may help identification of previously undiagnosed asthmatic patients.

    Key messages

    • One third of young people with asthma are not diagnosed; most are girls

    • Undiagnosed asthma is associated with low physical activity, high body mass index, serious family problems, passive smoking, and the absence of symptoms of rhinitis

    • Cough is the most common symptom among those with undiagnosed asthma

    • Two thirds of those with undiagnosed asthma do not report their symptoms to a doctor, suggesting a need for targeted asthma campaigns

    Footnotes

      • Accepted 2 October 1997

      Commentary: Risk factors for underdiagnosis of asthma in adolescence

      1. P Rees John, consultant physician
      1. a Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark
      2. b Department of Cardiology, Odense University Hospital
      3. c Centre for Health and Social Policy, Odense University, DK-5230 Odense M
      4. d Private Specialist Clinic, Nørregade 16, DK-5000 Odense C
      5. United Medical and Dental Schools of Guy's and St Thomas's Hospitals, London SE1 9RT
      6. London School of Hygiene and Tropical Medicine, London WC1
      7. Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark

          Commentary: Identifying the correct risks in diagnosis

          1. Stephen J W Evans, visiting professor of medical statistics
          1. a Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark
          2. b Department of Cardiology, Odense University Hospital
          3. c Centre for Health and Social Policy, Odense University, DK-5230 Odense M
          4. d Private Specialist Clinic, Nørregade 16, DK-5000 Odense C
          5. United Medical and Dental Schools of Guy's and St Thomas's Hospitals, London SE1 9RT
          6. London School of Hygiene and Tropical Medicine, London WC1
          7. Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark

              Commentary: Improving the diagnostic rate in asthma: a community issue

              1. Hans C Siersted, senior registrar
              1. a Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark
              2. b Department of Cardiology, Odense University Hospital
              3. c Centre for Health and Social Policy, Odense University, DK-5230 Odense M
              4. d Private Specialist Clinic, Nørregade 16, DK-5000 Odense C
              5. United Medical and Dental Schools of Guy's and St Thomas's Hospitals, London SE1 9RT
              6. London School of Hygiene and Tropical Medicine, London WC1
              7. Section of Respiratory Diseases, Department of Medicine C, Odense University Hospital, DK-5000 Odense C, Denmark
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