Juul LabsA new study of people who use Juul e-cigarettes provides further evidence that such products can reduce tobacco-related disease by offering smokers a much less hazarous source of nicotine. In a Juul-sponsored survey of nearly 19,000 vapers who had purchased the company's products online, the Centre for Substance Use Research, a Scottish consulting firm, found that smokers who had switched to vaping far outnumbered vapers who had switched to smoking.

A large majority of the Juul customers (87 percent) were current or former smokers when they first used one of the company's vaping devices. Of those who were smoking when they first tried Juul, 64 percent were no longer smoking, and more than three-quarters of that group said they had quit by switching to Juul. The "new former smokers" who had quit by switching to Juul represented 31 percent of the total sample.

Most of the Juul users who were still smoking (56 percent) had reduced their daily cigarette consumption by 50 percent or more. The respondents who had not quit but had reduced their smoking by at least half represented about 7 percent of the total sample.

By comparison, about 8 percent of the respondents who were former smokers when they started using Juul products had returned to smoking. They represented 2 percent of the total sample. About 2 percent of the respondents who had never smoked before trying Juul were smoking at the time of the survey, although the vast majority of them (more than nine out of 10) were not smoking every day. They represented 0.3 percent of the total sample.

These percentages are important because public health officials worry that e-cigarettes might lure people into smoking or cause former smokers to relapse. This survey suggests that sort of behavior is not very common. The number of smokers who quit after using Juul (7,520) was 137 times the number of never-smokers who started (55) and 21 times the number of former smokers who relapsed (359). In total, the people who went from smoking to vaping outnumbered the people who went from vaping to smoking by 18 to 1.

These results should be interpreted with caution because the survey was limited to online Juul customers and only 35 percent of the 89,000 or so people who were invited to participate agreed to do so. Eliminating respondents who did not meet the study's criteria and those who did not complete the survey left just 21 percent of the people who received invitations. The low response rate is cause for concern because people who had successfully used Juul to quit smoking might have been especially inclined to participate, meaning they would be overrepresented in the sample.

Even allowing for response bias, the survey shows it is not at all unusual for people to stop smoking after they begin vaping. It also suggests that vaping is more likely to be a gateway to cessation than a gateway to smoking, which is consistent with the continued downward trend in cigarette consumption. Firmer evidence for that hypothesis will require surveys with broader and more representative samples.