E-cigarettes have become increasingly popular among smokers in recent years, although a new study has revealed that some may contain enough alcohol to impair users’ psychomotor skills. Interestingly, affected participants claimed not to experience any of the subjective changes in consciousness that typically accompany alcohol consumption, meaning they may not have been aware of this impairment.
E-cigarettes normally contain a mixture of glycerol and propylene glycol, which is then vaporized in order to deliver nicotine to smokers. However, many e-cigarettes also include small concentrations of ethanol as an additional solvent. Levels are typically very low, and rarely exceed 3 percent, although the team behind the study found that in a sample of 31 commercially available e-liquids, this concentration ranged from 0.4 percent to 23.5 percent.
Publishing their findings in the journal Drug and Alcohol Dependence, the team describe how 20 volunteers were each given an e-cigarette containing an e-liquid with a particular concentration of alcohol, and directed to take 10 puffs over a five-minute period. This was followed by two 20-minute “ad-lib” puffing sessions, during which they were free to smoke as frequently as they wished.
They were then subjected to the Purdue Pegboard Dexterity Test, which involves picking up pins and placing them in sequential holes. This exercise is designed to test participants’ finger dexterity and overall coordination.
Results showed that those who had smoked e-cigarettes containing trace levels of alcohol (0.4 percent) displayed improved performance with each successive attempt at the test, while those who ingested higher concentrations did not. As such, the researchers conclude that high concentrations of alcohol in e-cigarettes has a notable impact on smokers’ psychomotor skills.
Urine samples were also taken after the experiment, with an alcohol metabolite called ethyl glucuronide being detectable in the samples given by three participants, all of whom had smoked an e-liquid containing 23.5 percent alcohol. Despite this, none of the volunteers claimed to notice the effects of the alcohol, and levels were not high enough to show up in their blood plasma.
Speaking to IFLScience, lead researcher Gerald Valentine explained that the impairment caused by inhaling alcohol “may represent a totally different phenomenon that can’t be equated with ingesting alcohol.” In other words, the effects of inhaling and drinking alcohol may manifest themselves in different ways, so the fact that smokers did not feel drunk should not be taken to mean that their judgement was not affected.
The ramifications of this phenomenon are potentially serious, although Valentine is keen to play down any sensationalism resulting from this study. “Based on our findings, if someone were to drive a car while smoking an e-cigarette with a high alcohol concentration, there would be some degree of impairment. Would this lead to a higher chance of accidents? Maybe, but I’m not necessarily going there.”
Rather, before drawing any conclusions regarding the dangers of e-cigarettes, he claims that more research is needed in order to discern how long these effects last and which aspects of smokers’ motor skills are most affected.
“At this point, I’m not saying that there are any acute safety implications,” he says. However, he insists that the information obtained from this and future studies “should be included in the regulatory framework” governing the manufacture of e-cigarettes, calling for increased vigilance over the quality of ingredients that go into e-liquids.
