E-cigarettes 'may damage lungs'

“Electronic cigarettes could 'damage your lungs' as they cause less oxygen to be absorbed by the blood,” reports the Daily Mail.

The news is based on a press release of preliminary findings of a small study investigating the short-term effects of smoking an ‘e-cigarette’, commonly known as ‘vaping’. The study looked at the lung function of non-smokers and smokers with and without lung conditions.

According to the press release, researchers found that ‘smoking’ a single e-cigarette for 10 minutes caused an increase in airway resistance, blocking the air getting into and out of the lungs.

Electronic cigarettes (e-cigarettes) are devices that mimic real cigarettes. They deliver nicotine through vapour rather than smoke. This method is thought to be potentially less harmful than smoking tobacco. Importantly, e-cigarettes are not regulated medicines so the ingredients and amount of nicotine contained within each e-cigarette may vary. The government’s medicines watchdog will decide next year whether to introduce stricter checks on e-cigarettes.

Limited conclusions can be drawn from the preliminary findings of this small study. The current press release suggests that the study adds weight to the growing evidence of the harmful effects of e-cigarettes.

There are far more well-established methods that can help you quit smoking, such as nicotine patches, gum and inhalers (collectively known as nicotine replacement therapy or NRT).

To order a free NHS QuitKit, visit the NHS Smokefree website.

Where did the story come from?

The study was carried out by researchers from the University of Athens in Greece. Sources of funding were not reported.

This story is based on a press release and conference abstract (a short summary of the findings) from the European Respiratory Society’s Annual Congress in Vienna in September 2012 presenting the initial findings of a study on e-cigarettes.

The study has not yet been published in a journal, and therefore has not been subjected to the peer-review process so findings reported should be treated with some caution.

What kind of research was this?

With only the press release available it is not possible to conduct a full appraisal of the design and methods of this study. The study is reported to have included 32 people and investigated the short-term effects of a single e-cigarette on their respiratory function.

From the press release it appears that this may be the earliest phase of a clinical trial, a phase 1 trial. These usually include small groups of people who all receive a small dose of the intervention in order to look primarily at its safety and effects on the body. Depending on the findings, phase 1 trials may be followed by further phase 2 trials looking at safety and effectiveness in larger groups of people. Finally, phase 3 trials may be conducted. These are randomised controlled trials which may compare the intervention to other standard treatment options.

What did the research involve?

Researchers recruited to their study 32 people. Of these:

eight were non-smokers
11 were smokers without existing lung conditions
13 were smokers with existing lung conditions, either chronic obstructive pulmonary disease (COPD) or asthma

Each participant smoked a single e-cigarette for 10 minutes and had their airway resistance measured using a number of different respiratory tests before and immediately afterwards. Respiratory tests carried out by the researchers included:

spirometry (a test looking at various measures of lung function)
static lung volume
airway conductance (a measure related to airway resistance)
single breath nitrogen test (a measure of how adequate inspiration and expiration is)

The abstract did not include details of the type or brand of e-cigarette used in the research, nor did it include the chemical make-up of the product, such as the dosage of nicotine.

What were the basic results?

According to the press release the main finding of the study was that smoking one e-cigarette for 10 minutes caused an immediate increase in airway resistance. This lasted for longer than 10 minutes in all of the 32 people, suggesting that air was not passing so easily through their airways.

When looking at the particular groups included in the study the findings were:

participants who were non-smokers (considered healthy subjects), had a significant increase in airway resistance from an average of 182% to 206%
participants who were smokers without lung conditions had a significant increase from an average of 176% to 220%
participants who were smokers with existing lung conditions (COPD or asthma), appeared to have no immediate effects on their airway resistance

How did the researchers interpret the results?

In discussing the study, one of the researchers, Professor Christine Gratziou said “we found an immediate rise in airway resistance in our group of participants, which suggests e-cigarettes can cause immediate harm after smoking the device”. She added that “more research is needed to understand whether this harm also has lasting effects in the long-term”.

Professor Gratziou who is also Chairman of the European Respiratory Society (ERS) Tobacco Control Committee also said, “the ERS recommends following effective smoking cessation treatment guidelines based on clinical evidence which do not advocate the use of such products”.

Current treatment guidelines recommend the use of NRT, such as nicotine patches and gum. There are also two types of medication, Zyban (bupropion) and Champix (varenicline), that can help people quit smoking.

Conclusion

The preliminary findings of this small study suggest the potential harmful effects of e-cigarettes on a person’s lung function. However, limited conclusions can be drawn from this press release and conference abstract. Scientific research is often presented first at conferences. It gives researchers a chance to speak about their results and discuss them with their peers. However, the results they present are often preliminary, and don’t have to go through the same peer-review quality assurance process that is needed for publication in a journal. Also, as conference presentations are summarised in very brief “abstracts” for the public, very limited details are usually available on the study’s methods and results. This makes it difficult to judge the study’s strengths and limitations.

However, the fact that the study included only 32 participants, all of whom were given a single e-cigarette in order to examine the effects upon lung function, suggests that this was the earliest stage of clinical research – a phase 1 trial. To draw further conclusions, larger studies will be required that include a large number of healthy participants as well as those with a range of lung conditions other than COPD and asthma. Also, according to the press release, each person’s respiratory function was only measured at two time intervals – before and immediately after the e-cigarette was used. Further studies would need to include longer follow-up and examine the effects of more than one e-cigarette in order to make any firm conclusions.

Some of the research presented at conferences never makes it to full publication. This could be for a number of reasons. For example, initially promising findings may not be confirmed in further study, or the research may not be accepted by peer reviewers or journal editors.

This doesn’t mean that all research presented at conferences isn’t reliable – just that it’s best to reserve judgement until the research has been completed and published in a peer-reviewed journal.

Given the growing popularity of ‘vaping’ as a perceived ‘safer’ option than smoking, it is notable that the newspapers – some of which carry large advertisements for these products – are highlighting the potential dangers of these products.

Read more about treatment and support to quit smoking.