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Can electronic cigarettes help people stop smoking or reduce the amount they smoke, and are they safe to use for this purpose?

Electronic cigarettes (EC) are electronic devices that produce a smoke-like aerosol (commonly referred to as vapour) that the user inhales. This vapour typically contains nicotine without most of the toxins smokers inhale with cigarette smoke. ECs have become popular with smokers who want to reduce the risks of smoking. This review aimed to find out whether ECs help smokers stop or cut down on their smoking, and whether it is safe to use ECs to do this.

Study characteristics
We searched for trials published up to July 2014 and found 13 that help answer these questions. Two of the trials compared ECs with and without nicotine. These studies were judged to be at low risk of bias. They were conducted in New Zealand and Italy, and measured whether people had quit smoking for at least six months. In one study, people wanted to quit smoking, but in the other study, they did not. The trial in people who wanted to quit smoking also compared ECs to nicotine patches. The rest of the studies did not put people into treatment groups so could not directly compare ECs with something else. These studies can tell us less about how ECs might help with quitting smoking or with cutting down.

Key results
Combined results from two studies, involving over 600 people, showed that using an EC containing nicotine increased the chances of stopping smoking long-term compared to using an EC without nicotine. Using an EC with nicotine also helped more smokers reduce the amount they smoked by at least half compared to using an EC without nicotine. We could not determine if EC was better than a nicotine patch in helping people stop smoking because the number of participants in the study was low. More studies are needed to evaluate this effect. This study showed that people who used EC were more likely to cut down the amount they smoked by at least half than people using a patch. The other studies were of lower quality, but they supported these findings. There was no evidence that using EC at the same time as using regular cigarettes made people less likely to quit smoking. None of the studies found that smokers who used EC short-term (for 2 years or less) had an increased health risk compared to smokers who did not use EC.

Quality of the evidence
The quality of the evidence overall is low because it is based on only a small number of studies. More studies of EC are needed. Some are already underway.

Citation: McRobbie H, Bullen C, Hartmann-Boyce J, Hajek P. Electronic cigarettes for smoking cessation and reduction. Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD010216. DOI: 10.1002/14651858.CD010216.pub2

Reduced dietary salt for the prevention of cardiovascular disease

Manual vs. Electric toothbrushes | Manual toothbrush| Electric toothbrush Cardiovascular disease includes heart attacks and strokes and is a major cause of premature death and disability. This is an update of a review first published in 2011. This review sets out to assess whether intensive support and encouragement to cut down on salt in foods, and substituting low-sodium salt, reduces the risk of death or cardiovascular disease. This update includes two new studies and eliminates one problematic study, giving a total of eight trials with 7284 participants.

Dietary advice and salt substitution did reduce the amount of salt eaten, which led to a small reduction in blood pressure by six months. There was weak evidence of benefit for cardiovascular events, but these findings were inconclusive and were driven by a single trial among retirement home residents, which reduced salt intake in the kitchens of the homes.

The findings of our review do not mean that advising people to reduce salt should be stopped. However, additional measures - reducing the amount of hidden salt in processed foods, for example – will make it much easier for people to achieve a lower salt diet. Overall many of the trials failed to report sufficient detail to assess their potential risk of bias. Further evidence of the effects of different ways of reducing dietary salt on clinical events is needed from experimental and observational studies to underpin public health policies.

Citation: Adler AJ, Taylor F, Martin N, Gottlieb S, Taylor RS, Ebrahim S. Reduced dietary salt for the prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD009217. DOI: 10.1002/14651858.CD009217.pub3

Healthcare interventions for consumers/public
The Cochrane Collaboration, is a not for profit organisation which produces systematic reviews on the effects of healthcare interventions. These reviews are published in an online database, The Cochrane Library monthly.

What is a systematic review?
A systematic review asks a specific research question about a particular healthcare intervention in a clearly defined group of people with a health condition or problem. These reviews summarise the results of healthcare studies and provides the evidence on the effectiveness of the interventions. Systematic reviews are complex and depend on what clinical trials have been conducted, the quality of the trials and the health outcomes that were measured. The review authors combine the numerical data about the effects of the treatment and the authors assess the benefits and harms for the specific treatment.1

For more information about what consumers can and cannot get from systematic reviews, please visit the Cochrane Consumer website.

The South African Cochrane Centre which is part of the Cochrane Collaboration, will publish consumer summaries monthly as listed below. Should you require information for a specific health condition please go to and search for the information you require or alternatively contact


1. Cochrane Consumer Network ( Accessed 17 August 2012

For more information, contact the South African Cochrane Centre on (021) 938 0834 or email
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Last updated:
13 January, 2015
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