Are there really 250 000 people vaping in Australia?

THE debate about electronic cigarettes has spawned a number of factoids: “facts” that become accepted as true because of their frequent repetition. “Vaping is 95% less risky than smoking” is one that has been recently eviscerated and shown to have a highly questionable provenance. Last year, I critically reviewed (here) another claim that smoking was increasing in Australia.

In recent weeks, it has been stated that there are 250 000 people using e-cigarettes in Australia, although the details on how that figure was calculated were not published (see “Vaping may have its drawbacks but it’s a lifesaver for many smokers”). Associate Professor Colin Mendelsohn also wrote in MJA Insight last month, based on overseas data, that “regular vaping by young people is rare and is almost exclusively confined to current or past smokers”.

Let’s take a look at this big, memorable number and the statement on young people and never-smokers.

Australian data on e-cigarette use

There are two main recent sources of data on e-cigarette use in Australia: the 2016 national data on e-cigarette use obtained by the Australian Institute of Health and Welfare (AIHW) from its National Drug Strategy Household Survey, and the Australian Secondary School Smoking, Alcohol and Drug Use Survey conducted in 2014.

If we apply the 2016 AIHW e-cigarette prevalence estimates to 2016 Australian census data, the table below shows there may be some 239 000 people currently vaping in Australia. Note, however, that this figure includes a large number of people who use e-cigarettes less frequently than once a month. If these are excluded, then the number comes down to fewer than 178 000.

As with the results of any survey, the estimates for population use of e-cigarettes are subject to sampling error, which means that the real percentages (and consequently the real numbers) might be considerably greater or fewer than that number. So, the number of people using e-cigarettes at least once in the previous month was somewhere between approximately 149 000 and 207 000. Whatever the true figure, and whether or not one excludes less-than-monthly trivial use, 250 000 looks like a considerable overestimate — almost 30% higher than the mid-point of 178 000.

Estimated percentage and numbers of resident population aged 14 years and over using e-cigarettes, Australia, 2016

 

	Smokers (14.9%) 2967837	Ex-smokers (22.8%) 4541389	Never-smokers (62.3%) 12409145	Total (100%) 19918371
Vaping daily	1.5% ± 0.5%	0.8% ± 0.3%	0.2%‡ ± 0.2%	0.5% ± 0.1%
Vaping at least weekly	1.2% ± 0.4%	0.1%† ± 0.1%	<0.1%† ± 0.1%	0.3% ± 0.1%
Vaping at least monthly	0.7% ± 0.3%	<0.1%‡ ± 0%	<0.1%† ± 0%	0.1% ± 0.1%
Use less than monthly	1.0% ± 0.4%	0.2%† ± 0.2%	0.2%† ± 0.1%	0.3% ± 0.1%
Calculated total vapers	4.3% ± 0.81% 127717 ± 23994	1.2% ± 0.35% 54497 ± 15953	0.4% ± 0.12% 49637 ± 15310	1.2% ± 0.17% 239020 ± 33434
Calculated total vapers excluding those who vape less than monthly	99854 ± 21328	42663 ± 14143	34060 ± 12690	177874 ± 28887
Ex-vaping, trivial use or never vaping
Used to use, but no longer use	6.8% ± 1.1%	1.7% ± 0.4%	0.3% ± 0.1%	1.6% ± 0.2%
Only tried once or twice	19.9% ± 1.7%	4.7% ± 0.7%	3.2% ± 0.4%	6.0% ± 0.4%
Never used	69.0% ± 1.9%	92.5% ± 0.9%	96.1% ± 0.5%	91.2% ± 0.5%
Total ex-, trivial and never use	95.7%	98.8%	99.6%	98.8%
Estimated numbers and % of current vapers by smoking status
Minimum	103623	38544	34327	205586
Mid-point	127617	54497	49637	239020
Maximum	151611	70450	64947	272455
% that this group makes up of total current vapers (using mid-point)	53%	23%	21%	100%

* 2016 National census data. † Estimate has a relative standard error of 25–50% and should be used with caution. ‡ Estimate has a high level of sampling error (relative standard error of 51–90%), meaning that it is unsuitable for most uses.

How many non-smokers are vaping?

Apart from the likely overestimate of the total number of vapers, there is concern about the potential extent of vaping among non-smokers, particularly among teenagers and others who have never smoked regularly. In the UK, 90% of vaping retailers are known to break the UK industry voluntary code by selling to non-smokers and to children.

As can be seen from the footnotes to the table above, the AIHW cautions that for five out of the six data cells for ex-smokers and never-smokers currently using e-cigarettes, the standard errors are large to very large, so that we cannot have confidence in the percentages provided. However, one cannot conclude from this that the total number of non-smokers who vape is therefore negligible. Looking down the columns one can see that, while a total of 98.8% of ex-smokers and 99.6% of never-smokers have never vaped, no longer vape or have only vaped a couple of times, this leaves 1.2% of ex-smokers and about 0.4% of never-smokers who currently vape at least to some degree.

While the percentages of ex-smokers and never-smokers vaping are much lower than the percentages of smokers who are currently vaping, the far greater numbers of ex-smokers and never-smokers compared to smokers in the Australian population means that the aggregated small percentages translate to larger, commercially beguiling numbers. Based on these figures, about 50 000 people (21% of current vapers) could be never-smokers. Applying confidence intervals, the number of never-smokers currently vaping could be anywhere between about 34 000 and 65 000.

Of even greater concern, it appears that a high percentage of these never-smokers who use e-cigarettes are young people, including teenagers.

So how many children?

In the 2016 National Drug Strategy Household Survey, 7.1% of respondents in the 12–17-year age range (including 6.2% of non-smokers) reported having ever used an e-cigarette.  It is instructive to note that in the 18–24-year old age group, ever use (at 19.2%), ever use among non-smokers (at 13.6%) and current use among smokers (at 6.8%) were the highest levels of use of any age group.

Corroborating evidence about the extent of use of e-cigarettes among teenagers comes from the Australian secondary school survey of smoking, alcohol and drug use which provides much more reliable estimates of drug use among teenagers of school age. In this very large survey of more than 23 000 students, we see in 2014 that 13.2% of 12–17-year old students (~ 229 000 Australia-wide, if equivalent rates were reflected in the whole population) had ever tried an e-cigarette, and that 3.3% ± 0.3% had vaped at least once in the last month (~ 56 850 Australia-wide); that is, again not a trivial number. No information is available about the proportion of student e-cigarette users who used more frequently than monthly, and this survey was conducted prior to the implementation of laws restricting sales of e-cigarettes to teenagers in several states. So, it is important to be careful in interpreting these figures and the risks they might point to. The 2017 Australian Secondary School Alcohol and Drug survey (results currently under analysis) should reveal whether use of e-cigarettes was a passing fad for Australian teenagers or has persisted as a serious concern.

Overall public health effects of vaping

Ex-smokers in the AIHW national survey can mean smokers who quit at any time, and thus include those who have not smoked for many years as well as those who quit in the days, weeks or few months prior to answering survey questions such as those asked by the AIHW. We do not know what proportion of ex-smokers who are vaping are those who quit with the help of their e-cigarette use and what proportion are long term ex-smokers who took up vaping after not smoking for many months or years. Neither do we know what proportion of the 1.7% who are both ex-smokers and ex-vapers quit because of their vaping, versus those who tried and failed to quit via vaping and later quit either unaided or using another method.

Importantly, a large proportion of people who describe themselves as ex-smokers when they answer a survey question will relapse back to smoking at a later date. The same is true for those ex-smokers who are currently vaping. So, triumphalism about large numbers of ex-smokers obtained from cross-sectional, snapshot surveys needs to be tempered.

The likely scale and consequences of each of various forms of “on-target” versus “off-target’’ use can only be assessed by surveying a very large cohort of smokers, ex-smokers and never-smokers and following them over a sufficient number of years. This will enable critical information to be gathered on vaping uptake by smokers, ex-smokers and non-smokers (especially children), duration of use, concomitant dual use of cigarettes and e-cigarettes, and smoking cessation and relapse rates comparing vaping with other approaches to quitting tobacco products.

Until this happens, e-cigarette advocates should be cautious about overhyping potential cessation benefits and dismissing potential risks.

Simon Chapman, AO, is Emeritus Professor of Public Health at the University of Sydney. He can be found on Twitter @simonchapman6

 

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