Substantial evidence of e-cigarette use among never and former smokers (both adults and youth): That's not harm reduction

E-cigarette enthusiasts, as well as much of the research on e-cigarettes, assumes that use will be concentrated among current smokers who are either using e-cigarettes to quit or reduce smoking. For example, the American Heart Association in its recent policy statement on e-cigarettes says, “Among never smokers, 0.7% were currently users (past 30 days), which indicates that few never smokers
who try e-cigarettes continue their use.”

Lauren Dutra and I recently reviewed the evidence that a substantial and growing minority of youth using e-cigarettes have never smoked conventional cigarettes.

There are several recent papers that show substantial e-cigarette use among never-smoking adults or adults who have long-since quit smoking.

Robert McMillen and colleagues used data from national surveys conducted between 2010 and 2013 to examine adult use of e-cigarettes. Consistent with earlier research, they found dramatic increases in e-cigarette use, from 1.8% in 2010 to 13.0% in 2013. Use among young adults (age 18-24) was highest, probably reflecting the heavy marketing directed at this group (which spills down to teens). While two-thirds of adults were current smokers, 32.5% of current e-cigarette users were never or former smokers.

That 32.5% includes 12.6% who are never smokers and 5.8% who quit smoking more than 5 years ago, before e-cigarettes entered the market. The other 14.1% are people who quit smoking less than 5 years ago so it is possible that some of them used e-cigarettes to quit smoking. What that means is that at least 18.4% – nearly 1 in 5 – e-cigarette users are people who would not be using nicotine and being exposed to the other toxins in e-cigarettes if e-cigarettes were not on the market.

The actual use of e-cigarettes among nonsmokers is likely higher than these numbers because McMillen and colleagues pooled the results for the four years in the analysis of nonsmokers’ use of e-cigarettes and use has been increasing over time.

Blair Coleman and colleagues help explain these findings, at least among young adults. They examined the relationship between openness to smoking conventional cigarettes among never-smoking (i.e., people who had not smoked 100 cigarettes in their lifetime and had not smoked in the last 30 days) young adults (age 18-29) in the 2012-2013 National Adult Tobacco Survey and found that young adults who used e-cigarettes were 2.4 times the odds of being open to cigarette smoking. (They found similar, but smaller, effects for hookah and cigars, but not smokeless tobacco.) The effect was 1.7 times higher among younger young adults (age 18-14), meaning that in this younger group e-cigarette users were 4.1 times (2.4 x 1.7) more likely to be open to smoking cigarettes than nonusers.

These results are consistent with the results in middle and high school students that Rebecca Bunnell and colleagues found in the 2011-2013 National Youth Tobacco Survey. They found that between 2011 and 2013 the number of never-smoking youth who used e-cigarettes increased 3-fold, from 79,000 to over 263,000. In addition, youth who were ever and current e-cigarette users had 1.7 and 1.9 times the odds of having smoking intentions than never e-cigarette users.

These results are also consistent with our finding (based on the 2011 National Youth Tobacco Survey) that among cigarette experimenters (>1 puff), ever e-cigarette use was associated with higher odds of ever smoking cigarettes (>100 cigarettes) by a factor of 6.3 and current cigarette smoking of 6.0.

As with the McMillen study, these effects are probably underestimated because much of the data were collected before the explosion of e-cigarette advertising that occurred in recent years.

These effects are substantial. It is time for e-cigarette enthusiasts (and policy makers) to seriously consider the effects of e-cigarettes on never or former tobacco users, whether adults or youth. Recruiting new people to (or back to) nicotine addiction is a bad thing. For these people the appropriate toxicity comparison is not with cigarettes but with not smoking anything at all.

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