Largely Ignored Study Shows that Switching from Smoking to E-Cigarettes Reduces Carcinogenic Exposures to the Same Extent as Complete Nicotine Abstinence

An important but largely ignored study published last week in the journal Biomarkers compared changes in exposure to toxic and carcinogenic chemicals among three groups: (1) smokers who switched completely to e-cigarettes; (2) smokers who continued to smoke their usual cigarette brand; and (3) smokers who discontinued all use of nicotine products (both cigarettes and e-cigarettes). A total of 89 smokers were randomized to one of these three groups for six days. Baseline measurements of biomarkers of exposure to carcinogens and toxins were compared to follow-up measurements after six days.

The results showed that there was massive reductions in biomarkers of carcinogenic and toxic exposures among those who switched from cigarettes to e-cigarettes. However, the most interesting finding was that the amount of reduction in these biomarkers of exposure among smokers who switched to e-cigarettes were not significantly different from the amount of reduction among smokers who quit all nicotine products completely.

For example, levels of 4-aminobiphenyl -- a known, potent carcinogen -- dropped by an average of about 90% among smokers who switched to e-cigarettes. A similar 90% drop occurred among smokers who abstained from nicotine products completely, and the difference between the magnitude of the reduction in the two groups was not statistically significant. 

Approximate reductions in exposure to other carcinogens among those who switched from cigarettes to e-cigarettes are shown below. In each case, the magnitude of the reduction in exposure was statistically equivalent between the group that switched to e-cigarettes and the group that abstained completely.

N'-nitrosonornicotine (proven human carcinogen): 85%

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (metabolite of a proven human carcinogen): 68%

2-Naphthylamine (proven human carcinogen): 85%

monohydroxylbutenyl-mercapturic acid (metabolite of a proven human carcinogen): 90%

S-phenyl-mercapturic acid (metabolite of a proven human carcinogen): 92%

3-hydroxy-1-methylpropyl-mercapturic acid (metabolite of a proven human carcinogen): 80%

2-cyanoethylmercapturic acid (metabolite of a proven human carcinogen): 85%

1-hydroxypyrene (metabolite of a proven human carcinogen): 75%

ortho-toluidine (proven human carcinogen): 65%

 

Thus, for the 10 carcinogens studied, there was between approximately a 65% and 92% reduction in exposure, in just six days, among smokers who switched to e-cigarettes.

The study concludes as follows: "Data from this randomized controlled study demonstrate that adults who switch completely from smoking cigarettes to use of a new pod-based ENDS product, JUUL2, were exposed to similar levels of nicotine relative to continued cigarette smoking and substantially reduced their exposure to multiple toxins associated with smoking-related disease. Additionally, reductions in exposure to such HPHCs among participants who switched to JUUL2 products were similar in magnitude to participants who stopped using tobacco and nicotine products entirely. This study extends prior evidence that ENDS can be effective harm reduction products to a new pod-based ENDS."

The Rest of the Story

This is a very important study but it has been largely, if not completely ignored by most tobacco control and health groups. These groups continue to claim that vaping is just as harmful as smoking, that there is no value in smokers quitting by switching to e-cigarettes, and that there are no health benefits to switching from real cigarettes to e-cigarettes.

This study demonstrates that there are immediate health benefits of switching from smoking to vaping and provides evidence that smokers who do so can greatly reduce their risk of cancer. The reduction in exposure demonstrated by this study probably underestimates the longer-term reductions because it takes a period of time before these toxins are cleared out of the body. For example, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol has a half-life of as much as 45 days, so it could take as long as seven months to completely clear it.

In spite of the findings of this study (and several others like it, including national studies with huge sample sizes), the American Cancer Society still claims that vaping causes cancer. Hopefully, smokers will not listen to what the American Cancer Society is saying and will choose to quit smoking by whatever means they can, including by switching to electronic cigarettes.