A new experimental study—the first of its kind, according to the authors—confirms that smokers can dramatically reduce their exposure to toxins and carcinogens by switching to e-cigarettes. "They are safer," the lead author, Maciej Goniewicz, a toxicologist at the Roswell Park Cancer Institute, told Buffalo Business First. "It's the first time we have very strong evidence that we will be able now to give [smokers] that the answer is, yes, this you should consider a transition, a substitute for your tobacco cigarette that will save your life."

The study, reported last week in the journal Nicotine & Tobacco Research, involved 20 Polish smokers who were encouraged to replace their cigarettes with the M201, a pen-style vaping system popular in Poland. Each week during the two-week experiment, the researchers supplied the subjects with 20 tobacco-flavored cartridges, each containing 11 milligrams of nicotine in a solution of propylene glycol and vegetable glycerin. Goniewicz and his colleagues used questionnaires and urine tests to assess the subjects at the beginning of the study, after a week, and after two weeks.

Nine of the subjects stopped smoking completely, while the rest cut back, from an average of 16 cigarettes a day at the beginning of the study to an average of just one a day at the end. Based on tests for seven nicotine metabolites, the researchers found that nicotine intake stayed the same, while exposure to tobacco-related toxins and carcinogens fell. Goniewicz et al. measured biomarkers for 13 toxins and carcinogens; all but a few declined substantially after the smokers started using e-cigarettes. For example, exposure to NNK, a tobacco-specific nitrosamine "directly associated with lung cancer risk," had fallen by 64 percent after the second week. Exposure to the volatile organic compounds acrolein, ethylene oxide, benzene, and 1,3-butadiene fell by 56 percent, 61 percent, 76 percent, and 84 percent, respectively.

"The observed decline in various urine toxicant biomarker levels in our study was similar to decline among smokers who have quit smoking completely and did not substitute with any other product," Goniewicz et al. write. "This observation suggests that e-cigarettes are not a significant source of exposure to those toxicants." Based on chemical analyses of e-cigarette vapor, other researchers have estimated that switching from smoking to vaping reduces health risks by at least 95 percent.

Goniewicz et al. also found declines in reports of chest tightness, visual disturbances, daytime coughing, difficulty concentrating, irritability, and phlegm, although only the first two changes were statistically significant. A larger sample with a longer follow-up period probably would supply further evidence of health improvement. The authors note that a 2014 survey of 19,000 e-cigarette users "suggest[s] use of these products pose minimal side effects to users and can in fact improve reported health issues experienced when using tobacco cigarettes," including respiratory symptoms caused by asthma and chronic obstructive lung disease.

"This study showed for the first time that after switching from tobacco to e-cigarettes, nicotine exposure remains unchanged, while exposure to selected carcinogens and toxicants is substantially reduced," Goniewicz et al. conclude. "These findings suggest that e-cigarettes may effectively reduce exposure to toxic and carcinogenic substances among smokers who switched to these products."