Acute and Short-term Effects of Secondhand Smoke on Lung Function and Cytokine Production

Abstract

The acute effect of secondhand smoke (SHS) on lung function and the duration of system disruption remain unknown. To assess the SHS effects and their duration on lung function and inflammatory markers. In a randomized single-blind crossover experiment data were obtained from 16 (8 women) nonsmoking adults at baseline and at 0, 1, and 3 hours after a 1-hour SHS exposure set at bar/restaurant SHS levels. Serum and urine cotinine, lung function, and cytokines IL-4, IL-5, IL-6, tumor necrosis factor (TNF)-alpha, and IFN-gamma. At 0 hours most lung function parameters were significantly reduced (indicative: FEV(1), 4.3 +/- 0.4 vs. 3.8 +/- 0.3 L; FEV(1)/FVC, 0.9 +/- 0.1 vs. 0.8 +/- 0.1; P < 0.05) but at 3 hours they were at baseline levels. In contrast, cotinine (serum, 8.9 +/- 3.2 vs. 35.5 +/- 10.2 ng x ml(-1)), IL-4 (41.3 +/- 5.8 vs. 44.2 +/- 4.5 pg x ml(-1)), IL-5 (36.1 +/- 3.2 vs. 60.1 +/- 7.0 pg x ml(-1)), IL-6 (2.5 +/- 0.3 vs. 7.6 +/- 1.4 pg x ml(-1)) and IFN-gamma (0.3 +/- 0.2 vs. 0.6 +/- 0.2 IU x ml(-1)) at 3 hours were higher than at baseline (P < 0.05). IL-4 and TNF-alpha increased only in men, whereas IL-5, IL-6, and IFN-gamma were different between sexes after exposure (P < 0.05). Regression analyses revealed inverse associations of FEV(1) and FEV(1)/FVC ratio with IL-5 (P < 0.05) in men and with IL-5 (P = 0.01), IL-6 (P < 0.001), IFN-gamma (P = 0.034) and serum cotinine (P < 0.001) in women. We conclude that 1 hour of SHS exposure at bar/restaurant levels is accompanied by significant decrements on lung function and marked increases in inflammatory cytokines, particularly in men. More importantly, whereas most smoke-induced effects on lung function appear to recede within 60 minutes, inflammatory cytokines remain elevated for at least 3 hours after exposure to SHS.