Effect of one hour of passive cigarette smoking on lung function and airway responsiveness in adults and children with asthma

Summary We exposed 18 adults with bronchial asthma, 16 healthy controls and 11 children with asthma for 1 h either to ambient air (AA) or to environmental tobacco smoke (ETS). Exposure was performed at rest in an exposure chamber. Before and after exposure symptom scores and lung function were determined. After exposure bronchoprovocation tests with methacholine (adults) or histamine (children) were performed to determine the concentrations causing a 100% increase in SRaw (PC₁₀₀SRaw), and a 20% fall in FEV₁ (PC_2OFEV₁). In adult asthmatics mean (SD) SRaw before and after Sham was 8.8 (3.6) and 8.4 (3.6) cmH₂O · s, and mean FEV₁ (SD) was 3.18 (0.97) and 3.14 (0.9) 1, respectively. Before and after passive smoking mean SRaw (SD) was 7.5 (3.0) and 7.2 (2.7) cmH₂O · s, and mean FEV₁ (SD) was 3.31 (1.0) and 3.21 (0.88) 1, respectively. Geometric mean (SD) PC₁₀₀SRaw and PC_2OFEV₁ after Sham were 0.38 (4.5) and 0.29 (4.1) mg/ml, after passive smoking 0.39 (5.1) and 0.36 (4.7) mg/ ml, respectively. In healthy controls there was no consistent effect on the respective parameters during exposure. In children mean (SD) SRaw before and after Sham was 8.7 (3.6) and 9.0 (3.2) cmH₂O · s, and mean FEV₁ (SD) was 1.97 (0.32) and 1.98 (0.40) 1, respectively. Before and after passive smoking mean SRaw (SD) was 10.4 (5.3) and 9.4 (3.3) cmH₂O · s, and mean FEV₁ (SD) was 1.95 (0.37) and 1.94 (0.35) 1, respectively. Geometric mean (SD) PC₁₀₀SRaw and PC₂₀FEV₁ after Sham were 1.39 (3.0) and 0.70 (2.7) mg/ml, and after passive smoking 1.65 (2.5) and 0.96 (2.3) mg/ml, respectively. There were no significant differences in lung function and airway responsiveness between exposure to ambient air or ETS. The main symptoms during passive smoking were eye and nasopharyngeal irritation. Our observations suggest that in children and adults with mild to moderate bronchial asthma, 1 h of passive cigarette smoking does not cause airway obstruction or con sistent changes in bronchial responsiveness.Abbreviations AA ambient air (Sham) - ETS environmental tobacco smoke - SRaw specific airway resistance - FEV₁a one-second forced expiratory volume - PC₂₀FEV₁a provocative concentrations of histamine/methacholine to decrease FEV₁ by 20% - PC₁₀₀SRaw provocative concentrations of histamine/methacholine to increase SRaw by 100%Supported by Forschungsrat Rauchen und Gesundheit, Hamburg, Federal Republic of Germany