Vaping does does significantly impede lung function according to an article in the journal of inhalation toxicology

Title Acute impact of active and passive electronic cigarette smoking on serum cotinine and lung function.
Source Inhalation Toxicology. 25(2):91-101, 2013 Feb.
Abstract 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+36.6ng/ml) and passive (2.4+0.9 versus 2.6+0.6ng/ml) smoking. Neither a brief session of active e-cigarette smoking (indicative: 3% reduction in FEV1/FVC) nor a 1h 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.

From MEDLINE, a database of the U.S. National Library of MedicineAuthors Flouris AD. Chorti MS. Poulianiti KP. Jamurtas AZ. Kostikas K. Tzatzarakis MN. Wallace Hayes A. Tsatsakis AM. Koutedakis Y.

Institution FAME Laboratory, Centre for Research and Technology Thessaly, Karies, Trikala, Greece. andreasflouris@gmail.com