American Journal of Epidemiology Advance Access originally published online on January 12, 2006
American Journal of Epidemiology 2006 163(4):384-391; doi:10.1093/aje/kwj052
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Practice of Epidemiology |
Agreement between Responses to a Standardized Asthma Questionnaire and a Questionnaire following a Demonstration of Asthma Symptoms in Adults
1 Department of Public Health Sciences, King's College London, London, United Kingdom
2 Institute of Bio-Medical Science, Faculty of Medicine, University of Chile, Santiago, Chile
Correspondence to Nigel C. Smeeton, Department of Public Health Sciences, King's College London, Capital House, Fifth Floor, 42 Weston Street, London SE1 3QD, United Kingdom (e-mail: nigel.smeeton{at}kcl.ac.uk).
Asthma epidemiology relies heavily on standardized questionnaires, but little is known about the understanding of asthma symptoms among adults in the community. In 2004, the authors assessed the level of agreement between responses to a standardized questionnaire and responses to a questionnaire completed by participants after viewing a demonstration of asthma symptoms. The study involved 601 young adults from Chile. The field-workers were trained to explain and demonstrate the asthma symptoms to the participants. The symptoms were wheeze, waking at night with breathlessness, breathlessness following exercise, and waking with cough. The kappa statistic did not exceed 0.4, and the recorded prevalence of asthma symptoms following the demonstration was 30–60% lower than that for the standardized questionnaire. Using bronchial responsiveness as the proxy gold standard, the positive likelihood ratios for wheeze and waking short of breath were higher following symptom demonstration. The low agreement between the standardized questionnaire and the postdemonstration questionnaire and the likelihood ratios' closeness to 1 for the standardized questionnaire decreases the authors' confidence in the appropriateness of this tool for estimating the prevalence of asthma in the community. For etiologic studies of asthma, it may contribute to the lack of consistency between different studies analyzing the same etiologic exposures.
asthma; data collection; epidemiologic methods; questionnaires; statistics
Abbreviations: ECRHS, European Community Respiratory Health Survey; FEV1, forced expiratory volume in 1 second; ISAAC, International Study of Asthma and Allergies in Childhood