Respiratory Effects of Environmental Tobacco Exposure are Enhanced by Bronchial Hyperreactivity.

Am J Respir Crit Care Med. 2006 Aug 24;
Gerbase MW, Schindler C, Zellweger JP, Kunzli N, Downs SH, Brandli O, Schwartz, Frey M, Burdet L, Rochat T, Ackermann-Liebrich U, Leuenberger P.
Division of Pulmonary Medicine, University Hospitals of Geneva, Geneva, Switzerland.

Rationale: 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 1661 never smokers from the SAPALDIA cohort, assessed in 1991 (baseline) and 11 years later, who were symptom-free at baseline. Incident reports of respiratory symptoms and results of spirometry were assessed at the follow-up survey.

Main Results: Exposure to ETS reported in the two surveys was strongly associated with the development of cough (OR, 2.1; 95%CI, 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 FEF25-75/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 to non exposed subjects without BHR. Lower values were found in subjects continuing exposure by the follow-up survey.

Conclusion: Exposure to ETS was strongly associated with the development of respiratory symptoms in previously asymptomatic subjects with BHR within eleven years. 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.




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