British researchers have looked at the effects that e-cigarettes can have on the respiratory system and they have found evidence suggesting the vapor can disable important immune cells in the lungs, which could lead to inflamed tissues.

In the study, published in the British Medical Journal Thorax, the team discusses the effect that e-cigarette liquid and vapor have on alveolar macrophage, the principal immune system response in the lungs that get rid of infectious, toxic, or allergic particles from the respiratory organs. The team found a more severe decline in a culture of these cells when they were exposed to the vapor compared directly to the liquid.

The research is a first step in understanding the effect that vaping might have on humans, but it is not yet a complete picture. The authors state that further research is actually needed to completely assess the effects, but this work shows that the idea that e-cigarettes are completely safe is questionable.

“I don't believe e-cigarettes are more harmful than ordinary cigarettes – but we should have a cautious skepticism that they are as safe as we are being led to believe,” senior author Professor David Thickett from the University of Birmingham stated. “They are safer in terms of cancer risk – but if you vape for 20 or 30 years and this can cause COPD [chronic obstructive pulmonary disease], then that's something we need to know about.”

The study shows that e-cigarette vapor can do harm although it is not certain it will do harm. The researchers themselves admit that it is difficult to recreate real-life conditions in the lab. Other experts also suggest looking at the bigger picture: Most e-cigarette users are current or former smokers, so the potential damage needs to be in comparison to regular cigarettes.

“[A] key question is how this adverse effect compares with that of exposure to cigarette smoke. The current study does not address that question, but given the much lower levels and range of toxins in electronic cigarette vapor relative to cigarette smoke, the answer is likely to be substantially less,” Professor John Britton, Director of the UK Centre for Tobacco & Alcohol Studies at the University of Nottingham, who was not involved in the study, told the Science Media Centre.

“The harsh truth is that smoking kills, and smokers who switch completely to electronic cigarettes are likely substantially to reduce the likelihood of premature death and disability.”

E-cigarettes are widely recognized by health organizations as potentially harmful, though better than cigarettes, although their full health effects are yet to be fully understood.

[H/T: BBC News]