Acute impact of active and passive electronic cigarette smoking on serum cotinine and lung function

Context: Electronic cigarettes (e-cigarettes) are becoming increasingly popular yet their effects on health remain unknown. Objective: To conduct the first comprehensive and standardized assessment of the acute impact of active and passive e-cigarette smoking on serum cotinine and lung function, as compared to active and passive tobacco cigarette smoking. Materials and methods: Fifteen smokers (>= 15 cigarettes/day; seven females; eight males) and 15 never-smokers (seven females; eight males) completed this repeated-measures controlled study. Smokers underwent a control session, an active tobacco cigarette (their favorite brand) smoking session and an active e-cigarette smoking session. Never-smokers underwent a control session, a passive tobacco cigarette smoking session and a passive e-cigarette smoking session. Serum cotinine, lung function, exhaled carbon monoxide and nitric oxide were assessed. The level of significance was set at p <= 0.001 to adjust for multiple comparisons. Results: e-Cigarettes and tobacco cigarettes generated similar (p>0.001) effects on serum cotinine levels after active (60.6 +/- 34.3 versus 61.3 +/- 36.6 ng/ml) and passive (2.4 +/- 0.9 versus 2.6 +/- 0.6 ng/ml) smoking. Neither a brief session of active e-cigarette smoking (indicative: 3% reduction in FEV1/FVC) nor a 1 h passive e-cigarette smoking (indicative: 2.3% reduction in FEV1/FVC) significantly affected the lung function (p>0.001). In contrast, active (indicative: 7.2% reduction in FEV1/FVC; p<0.001) but not passive (indicative: 3.4% reduction in FEV1/FVC; p=0.005) tobacco cigarette smoking undermined lung function. Conclusion: Regarding short-term usage, the studied e-cigarettes generate smaller changes in lung function but similar nicotinergic impact to tobacco cigarettes. Future research should target the health effects of long-term e-cigarette usage, including the effects of nicotine dosage.