Cochrane’s April Update

Posted 6th May 2022 by Dave Cross
The Cochrane Tobacco Addiction Group conducts a monthly review of studies looking at the use of e-cigarettes to help people stop smoking. It has issued an updated briefing (April 2022) that contains all the new information published in peer-reviewed journals.

The Cochrane Tobacco Addiction Group is a highly respected independent organisation that reviews all evidence regardless of outcome. It attributes a level of confidence in the findings to the work and factors it into its conclusions. The work done by the Tobacco Addiction Group then feeds into decision making processes by employers, public health professionals and national policy makers in government.

The researchers responsible for the Group’s work explain why it is important: “Stopping smoking reduces the risk of getting lung cancer and other diseases. Many people find it difficult to quit. We want to find out if e-cigarettes can help and if people using them experience any unwanted effects.”

Each month we are searching for studies that look at the use of e‐cigarettes to help people stop smoking. As we search monthly this is called a living systematic review. We look for randomized controlled trials, in which the treatments people received were decided at random. This type of study usually gives the most reliable evidence about the effects of a treatment. We also search for studies in which everyone received an e‐cigarette treatment.”

This latest update includes an additional 61 pieces of work.

The studies we looked at compared electronic cigarettes to nicotine replacement therapy (for example, patches or gum), to stop smoking medication (varenicline), to non- nicotine e-cigarettes, and to behavioural support or no support.”

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They look for evidence of changes in lung function, changes in carbon monoxide levels, how heart rate is effected, changes in blood pressure, and if there is any indication of serious harm associated with e-cig use.

  • Lung function was improved in people using e- cigarettes compared to people using nicotine replacement therapy. No difference was found when e- cigarettes were compared to non-nicotine e-cigarettes or to usual care. Five of the 61 studies reported data on at least one measure of lung function.
  • In most studies carbon monoxide levels were lower in those using e-cigarettes. 39 of the 61 studies reported data on carbon monoxide.
  • Most studies showed lowered heart rate in people using e-cigarettes. Nine of the 61 studies reported data on heart rate.
  • Most studies found no difference, in 3 studies blood pressure measures were improved with e-cigarettes and in one study these were improved in the usual care group. Of the 61 included studies, 12 reported data on blood pressure and 2 studies reported data on blood oxygen levels.
  • The number of people experiencing serious harms was low across all study arms. We did not detect evidence of harm from nicotine e-cigarettes, but the longest follow-up was two years and the number of studies was small.

As far as efficacy goes, they say that the evidence shows vaping is the best quit tool: “Electronic cigarettes probably help more people to stop smoking than other smoking cessation aids. For every 100 people using nicotine e-cigarettes to stop smoking, 9 to 14 might successfully stop, compared with only 6 of 100 people using nicotine-replacement therapy, 7 of 100 using nicotine-free e-cigarettes, or four of 100 people receiving no support or behavioural support only.”

Assistant Professor Jamie Hartmann-Boyce and Dr Nicola Lindson discuss this emerging evidence in e-cigarette research in the latest episode of the “Let’s talk e-cigarettes” podcast.


 Dave Cross
Article by Dave Cross
Freelance writer, physicist, karateka, motorbikes, and dog walker