title: Incidence of chronic obstructive pulmonary disease in a cohort of young adults according to the presence of chronic cough and phlegm.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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 (FEV(1)/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 FEV(1)/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.
  
  
  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.
authors.affiliation: 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. roberto.demarco@univr.it
authors.forename: Roberto
authors.initials: R
authors.lastname: de Marco
authors.forename: Simone
authors.initials: S
authors.lastname: Accordini
authors.forename: Isa
authors.initials: I
authors.lastname: Cerveri
authors.forename: Angelo
authors.initials: A
authors.lastname: Corsico
authors.forename: Josep M
authors.initials: JM
authors.lastname: Antó
authors.forename: Nino
authors.initials: N
authors.lastname: Künzli
authors.forename: Christer
authors.initials: C
authors.lastname: Janson
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Deborah
authors.initials: D
authors.lastname: Jarvis
authors.forename: Susan
authors.initials: S
authors.lastname: Chinn
authors.forename: Paul
authors.initials: P
authors.lastname: Vermeire
authors.forename: Cecilie
authors.initials: C
authors.lastname: Svanes
authors.forename: Ursula
authors.initials: U
authors.lastname: Ackermann-Liebrich
authors.forename: Thorarinn
authors.initials: T
authors.lastname: Gislason
authors.forename: Joachim
authors.initials: J
authors.lastname: Heinrich
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Leynaert
authors.forename: Françoise
authors.initials: F
authors.lastname: Neukirch
authors.forename: Jan P
authors.initials: JP
authors.lastname: Schouten
authors.forename: Matthias
authors.initials: M
authors.lastname: Wjst
authors.forename: Peter
authors.initials: P
authors.lastname: Burney
mesh_terms: D000328:Adult; D002908:Chronic Disease; D015331:Cohort Studies; D003371:Cough / Q000175:diagnosis*; D004417:Dyspnea / Q000175:diagnosis; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009093:Mucus; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*