title: Respiratory effects of environmental tobacco exposure are enhanced by bronchial hyperreactivity.
abstract: BACKGROUND
  Exposure to environmental tobacco smoke (ETS) is associated with increased reports of respiratory symptoms and reduced lung function, but the long-term effects of ETS are unclear, notably in healthy individuals with bronchial hyperresponsiveness (BHR).
  
  
  OBJECTIVE
  To assess the longitudinal effects of ETS exposure on the development of respiratory symptoms and spirometry in subjects with BHR.
  
  
  METHODS
  The study population included 1,661 never-smokers from the SAPALDIA (Swiss Study on Air Pollution and Lung Diseases in Adults) cohort, assessed in 1991 (baseline) and 11 yr later, who were symptom-free at baseline. Incident reports of respiratory symptoms and results of spirometry were assessed at the follow-up survey.
  
  
  RESULTS
  Exposure to ETS reported in the two surveys was strongly associated with the development of cough (odds ratio, 2.1; 95% confidence interval, 1.2-3.7; p = 0.01). In subjects with BHR exposed to ETS at both surveys, a trend for strong associations were observed for wheeze, cough, dyspnea, and chronic bronchitis; however, the association reached statistical significance only for the symptom of dyspnea (p < 0.01). Lower FEV1/FVC (mean +/- SD, 72.9 +/- 7.7 vs. 76.8 +/- 6.1%; p < 0.01) and FEF(25-75) (forced expiratory flow, midexpiratory phase)/FVC (mean +/- SD, 56.1 +/- 22.5 vs. 68.1 +/- 21.6%; p < 0.01) were observed in subjects with BHR exposed to ETS compared with nonexposed subjects without BHR. Lower values were found in subjects continuing exposure by the follow-up survey.
  
  
  CONCLUSIONS
  Exposure to ETS was strongly associated with the development of respiratory symptoms in previously asymptomatic subjects with BHR within 11 yr. Furthermore, subjects with underlying BHR had reduced lung function at follow-up, thus suggesting a higher risk for the development of chronic respiratory disease in this subset of the population.
authors.affiliation: Division of Pulmonary Medicine, University Hospitals of Geneva, 24 rue Micheli-du-Crest, 1211 Geneva 14, Switzerland. margaret.gerbase@hcuge.ch
authors.forename: Margaret W
authors.initials: MW
authors.lastname: Gerbase
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Zellweger
authors.forename: Nino
authors.initials: N
authors.lastname: Künzli
authors.forename: Sara H
authors.initials: SH
authors.lastname: Downs
authors.forename: Otto
authors.initials: O
authors.lastname: Brändli
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Martin
authors.initials: M
authors.lastname: Frey
authors.forename: Luc
authors.initials: L
authors.lastname: Burdet
authors.forename: Thierry
authors.initials: T
authors.lastname: Rochat
authors.forename: Ursula
authors.initials: U
authors.lastname: Ackermann-Liebrich
authors.forename: Philippe
authors.initials: P
authors.lastname: Leuenberger
mesh_terms: D000328:Adult; D016535:Bronchial Hyperreactivity / Q000503:physiopathology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012135:Respiratory Sounds / Q000503:physiopathology; D012140:Respiratory Tract Diseases / Q000503:physiopathology*; D013147:Spirometry; D014028:Tobacco Smoke Pollution
chemical_list: D014028:Tobacco Smoke Pollution