Short-term effects of a nicotine-free e-cigarette compared to a traditional cigarette in smokers and non-smokers

BACKGROUND A few studies have assessed the short-term effects of low-dose nicotine e-cigarettes, while data about nicotine-free e-cigarettes (NF e-cigarettes) are scanty. Concerns have been expressed about the use of NF e-cigarettes, because of the high concentrations of propylene glycol and other compounds in the e-cigarette vapor. METHODS This laboratory-based study was aimed to compare the effects of ad libitum use of a NF e-cigarette or and a traditional cigarette for 5 min in healthy adult smokers (n = 10) and non-smokers (n = 10). The main outcome measures were pulmonary function tests, fraction of exhaled nitric oxide (FeNO) and fractional concentration of carbon monoxide (FeCO) in exhaled breath. RESULTS The traditional cigarette induced statistically significant increases in FeCO in both smokers and non-smokers, while no significant changes were observed in FeNO. In non-smokers, the traditional cigarette induced a significant decrease from baseline in FEF75 (81 % ± 35 % vs 70.2 % ± 28.2 %, P = 0.013), while in smokers significant decreases were observed in FEF25 (101.3 % ± 16.4 % vs 93.5 % ± 31.7 %, P = 0.037), FEV1 (102.2 % ± 9.5 % vs 98.3 % ± 10 %, P = 0.037) and PEF (109.5 % ± 14.6 % vs 99.2 % ± 17.5 %, P = 0.009). In contrast, the only statistically significant effects induced by the NF e-cigarette in smokers were reductions in FEV1 (102.2 % ± 9.5 % vs 99.5 ± 7.6 %, P = 0.041) and FEF25 (103.4 % ± 16.4 % vs 94.2 % ± 16.2 %, P =  .014). DISCUSSION The present study demonstrated that the specific brand of NF e-cigarette utilized did not induce any majoracute effects. In contrast, several studies have shown that both traditional cigarettes and nicotine-containing e-cigarettes have acute effects on lung function. Our study expands on previous observations on the effects of NF e-cigarettes, but also for the first time describes the changes induced by smoking one traditional cigarette in a group of never smokers. CONCLUSIONS The short-term use of the specific brand of NF e-cigarette assessed in this study had no immediate adverse effects on non-smokers and only small effects on FEV1 and FEF25 in smokers. The long-term health effects of NF e-cigarette use are unknown but worthy of further investigations. TRIAL REGISTRATION Clinicaltrials.gov: NCT02102191.