Claim that vaping lacks evidence for quitting is misleading and wrong
Posted on November 9, 2020
IN A SUBMISSION to the Senate Inquiry into Tobacco Harm Reduction, Professor Emily Banks claims that there is insufficient evidence that e-cigarettes are an effective aid for quitting smoking. ATHRA believes her claim is misleading and incorrect for two major reasons.
Professor Banks is a distinguished epidemiologist who leads Greg Hunt’s scientific inquiry into vaping at the Australian National University. ATHRA has previously critiqued the preliminary report in an earlier blog.
Professor Banks and her team examined all the randomised controlled trials (RCTs) comparing the effectiveness of vaping to nicotine replacement therapy (NRT, such as nicotine patches and gum). They then created a meta-analysis (pooling the results from what they regarded as the best studies) which can be found here.
We believe their conclusion is flawed for two main reasons.
1. Poor study selection
The Banks analysis drew on three studies comparing vaping to nicotine replacement products.
However, one of the included studies used a vaping device with (effectively) no nicotine. This study by Lee used a nicotine concentration of 0.01 mg/mL, which is so low it would have no effect whatsoever. It is 1600 times lower than the lowest dose used in the other studies. While technically this vaping device does contain traces of nicotine, the Cochrane review classified this study as nicotine-free.
The two other studies used typical nicotine concentrations of 16mg/mL (Bullen) and 18mg/mL (Hajek) and together showed that vaping nicotine was 67% more effective than nicotine replacement therapy (RR 1.67).
However, including the study by Lee negates the effect of the other studies and produces a null result.
|2mg nicotine gum
|combination of patch
and other products
It is misleading and disingenuous to include a study which effectively uses a nicotine-free vaping product and then claim that vaping is not effective. In the real world, smokers use nicotine in their vaping devices.
Comparison with other meta-analyses
Banks says, “The results of this systematic review are broadly consistent with the conclusions of … more contemporary systematic reviews and meta-analyses”.
However, three recent meta-analyses found a very different result. The recent 2020 Cochrane review, an analysis commissioned by the Royal Australian College of General Practitioners and a third analysis by Grabovac, all used studies with standard nicotine doses and all concluded that nicotine vaping was 70% more effective than NRT. None of these meta-analyses included the Lee 2019 study.
2. RCTs only part of the story
Professor Banks concluded that there is not enough evidence to show that vaping is effective. However, her conclusion is based only on the RCTs she selected and does not include all the other available evidence.
RCTs indicate that a treatment works in a controlled research environment. However real-world studies can provide valuable additional information. They include observational, population studies and the changes in national smoking rates in countries where vaping is readily available. (Mendelsohn 2020)
Each type of study has benefits and limitations but combining and triangulating the results provides compelling evidence that vaping helps smokers quit
Real world studies add to the confidence that vaping is having a beneficial effect. The more robust observational studies found that vaping increases quit attempts and quitting smoking. (Villanti 2017; Glasser 2017)
Large population studies in the USA and the UK have found that smokers who use nicotine vaping to quit have significantly higher quit success rates than those who do not. [6-11] A US study of nearly 23,000 smokers found that those who used a vaping device were 73% more likely to quit than non-users. A similar study of 60,000 smokers found that those who were vaping were 65% more likely to have quit smoking.
The rate of decline in smoking in both the USA and United Kingdom has accelerated over the period that vaping has become widespread and population quit rates have increased. It is likely that vaping is playing an important role in this. In comparison, smoking rates have declined much more slowly where vaping is less accessible, such as in Australia.
The Banks meta-analysis included a study of a device which is effectively nicotine-free. Nicotine-free devices are rarely used in the real world for quitting smoking, so the conclusions from this analysis are misleading in guiding the role for vaping. Three other recent analyses of studies which only used devices with nicotine found vaping was 70% more effective than NRT.
As well as RCTs, any overall assessment of the effectiveness of vaping should include the abundant studies of vaping in the real world. Combining all the evidence provides compelling evidence that vaping is effective and is more effective than NRT.
Posted by Colin Mendelsohn, firstname.lastname@example.org