Laboratory and clinical acute effects of active and passive indoor group water-pipe (narghile) smoking

Background: Indoor group water-pipe tobacco smoking, commonly referred to as water-pipe smoking (WPS), especially in coffee shops, has gained worldwide popularity. We performed a comprehensive laboratory and clinical evaluation of the acute effects of active and passive indoor group WPS. Methods: This comparative study evaluated pre- and post-30-min active and passive indoor group WPS. The outcome parameters were carboxyhemoglobin (COHb), nicotine, and cotinine levels; CBC count; and cardiorespiratory parameters. Exhaled breath condensate (EBC) cytokines and endothelial function (using the EndoPat device [Itamar Medical Ltd]) were measured only in active smokers. Statistical methods used were Student t test, Wilcoxon signed rank test, Fisher exact test, analysis of variance, and Newman-Keuls post hoc test where relevant. Results: Sixty-two volunteers aged 24.9 ± 6.2 years were included; 47 were active smokers, and 15 were passive smokers. COHb level increased postactive WPS (active smokers, 2.0% ± 2.9% vs 17.6% ± 8.8%; P < .00001); six subjects (12.7%) had a > 25% increase, and two subjects (4.2%) had a . 40% increase. Plasma nicotine level increased postactive WPS (active smokers, 1.2 ± 4.3 ng/mL vs 18.8 ± 13.9 ng/mL; P < .0001); plasma cotinine and urinary nicotine and cotinine levels also increased significantly. EBC IL-4, IL-5, IL-10, IL-17, and γ-interferon decreased significantly with postactive smoking; endothelial function did not change. WPS was associated with adverse cardiorespiratory changes. In passive smokers, COHb level increased (0.8% ± 0.25% vs 1.2% ± 0.8%, respectively, P = .003) as did respiratory rate. Conclusions: One session of active indoor group WPS resulted in significant increases in COHb and serum nicotine levels (eightfold and 18-fold, respectively) and was associated with adverse cardiorespiratory health effects. The minor effects found in passive smokers suggest that they too may be affected adversely by exposure to WPS. The results call for action to limit the continuing global spread of WPS in coffee shops.