Incidence of Chronic Obstructive Pulmonary Disease in a Cohort of Young Adults According to the Presence of Chronic Cough and Phlegm
- Roberto de Marco,
- Simone Accordini,
- Isa Cerveri,
- Angelo Corsico,
- Josep M. Antó,
- Nino Künzli,
- Christer Janson,
- Jordi Sunyer,
- Deborah Jarvis,
- Susan Chinn,
- Paul Vermeire,
- Cecilie Svanes,
- Ursula Ackermann-Liebrich,
- Thorarinn Gislason,
- Joachim Heinrich,
- Bénédicte Leynaert,
- Françoise Neukirch,
- Jan P. Schouten,
- Matthias Wjst and
- Peter Burney
- Unit of Epidemiology and Medical Statistics, Department of Medicine and Public Health, University of Verona, Verona; Division of Respiratory Diseases, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico “San Matteo” Hospital, University of Pavia, Pavia, Italy; Institut Municipal d'Investigaciò Mèdica, Universitat Pompeu Fabra, Barcelona, Spain; Keck School of Medicine, University of Southern California, Los Angeles, California; Department of Medical Sciences, Respiratory Medicine, and Allergology, University of Uppsala, Uppsala, Sweden; Respiratory Epidemiology and Public Health Group, National Heart and Lung Institute, Imperial College, London; Department of Public Health Sciences, King's College London, London, United Kingdom; Campus Drie Eiken, University of Antwerp, Antwerp, Belgium; Department of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway; Institute of Social and Preventive Medicine, University of Basel, Basel, Switzerland; Department of Allergy, Respiratory Medicine and Sleep, Landspitali University Hospital, Reykjavik, Iceland; Institute of Epidemiology, Gesellschaft für Strahlen Forschung–National Research Center for Environment and Health, Neuherberg; Institute of Epidemiology, Ludwig-Maximilians-University of Munich, Neuherberg, Germany; Institut National de la Santé et de la Recherche Médicale, Unit 408—Epidemiology, Faculty of Medicine X Bichat, Paris, France; and Department of Epidemiology and Bioinformatics, University Medical Center, University of Groningen, Groningen, The Netherlands
- Correspondence and requests for reprints should be addressed to Roberto de Marco, Ph.D., Sezione di Epidemiologia & Statistica Medica, Dipartimento di Medicina e Sanità Pubblica, Università degli Studi di Verona, c/o Istituti Biologici II, Strada Le Grazie 8 37134, Verona, Italy. E-mail: roberto.demarco{at}univr.it
Abstract
Rationale: The few prospective studies aimed at assessing the incidence of chronic obstructive pulmonary disease (COPD) in relation to the presence of chronic cough/phlegm have produced contrasting results.
Objectives: To assess the incidence of COPD in a cohort of young adults and to test whether chronic cough/phlegm and dyspnea are independent predictors of COPD.
Methods: An international cohort of 5,002 subjects without asthma (ages 20–44 yr) with normal lung function (FEV1/FVC ratio ⩾ 70%) from 12 countries was followed from 1991–2002 in the frame of the European Community Respiratory Health Survey II. Incident cases of COPD were those who had an FEV1/FVC ratio less than 70% at the end of the follow-up, but did not report having had a doctor diagnose asthma during the follow-up.
Main Results: The incidence rate of COPD was 2.8 cases/1,000/yr (95% confidence interval [CI], 2.3–3.3). Chronic cough/phlegm was an independent and statistically significant predictor of COPD (incidence rate ratio [IRR], 1.85; 95% CI, 1.17–2.93) after adjusting for smoking habits and other potential confounders, whereas dyspnea was not associated with the disease (IRR = 0.98; 95% CI, 0.64–1.50). Subjects who reported chronic cough/phlegm both at baseline and at the follow-up had a nearly threefold-increased risk of developing COPD with respect to asymptomatic subjects (IRR = 2.88; 95% CI, 1.44–5.79).
Conclusions: The incidence of COPD is substantial even in young adults. The presence of chronic cough/phlegm identifies a subgroup of subjects with a high risk of developing COPD, independently of smoking habits.
- Received March 15, 2006.
- Accepted September 27, 2006.
- © 2007 The American Thoracic Society
