REUTERS: Vapers inhale significantly lower levels of toxic chemicals than smokers of traditional cigarettes, a new study suggests.
Compared to nonsmokers, vapers had more biomarkers of toxic chemicals in their urine - but they had lower levels than smokers of traditional cigarettes, said study leader Maciej Goniewicz of the Roswell Park Cancer Center.
"For smokers trying to quit it might be beneficial to use e-cigarettes as a transition," he added.
But some e-cigarette users may end up both vaping and smoking, the study suggests. A significant number of people surveyed were "dual users," with biomarkers showing higher consumption of both nicotine and toxicants, Goniewicz noted.
"E-cigarettes are a benefit to smokers only if they completely switch to vaping," Goniewicz said. "And we know from epidemiological studies that dual use is very common. Some people use e-cigarettes in environments where they are not allowed to smoke and then smoke at home."
The number of people who were both vaping and smoking "was really surprising," Goniewicz said.
Goniewicz and colleagues analyzed 2013-2014 data from the nationally representative Population Assessment of Tobacco and Health Study, which is designed to assess tobacco use and health in the U.S. The 5,105 adult participants provided urine samples to be analyzed for biomarkers.
Overall, 2,411 of the volunteers smoked cigarettes only, 247 used only e-cigarettes, 792 used both traditional and e-cigarettes and 1,655 never vaped nor smoked, researchers reported in JAMA Network Open.
Dual users had the highest levels of nicotine biomarkers, followed by those who smoked traditional cigarettes only. Biomarkers for the heavy metals lead and cadmium were lower in vapers than smokers, but still significantly higher in vapers than nonsmokers.
Exposure to cancer-causing tobacco-specific nitrosamines was far higher in smokers and those who both vaped and smoked, compared to those who used e-cigarettes only or never used tobacco. The same was true for several other toxic substances.
Experts said the study helps clarify health risks related to e-cigarettes.
"Use of e-cigarettes has risen significantly and we're all trying to figure out the potential risks and benefits compared to combustible cigarettes," said Dr. Michael Lynch, a toxicologist and emergency medicine physician and medical director of the Pittsburgh Poison Center at the University of Pittsburgh Medical Center. "But the results should be taken as preliminary, as they don't have as many pure e-cigarette users as they do combustible cigarette users."
It's hoped that e-cigarettes will be more helpful for smoking cessation than nicotine patches and gum, said Lynch, who was not involved in the study. "It fulfills the same fixation of putting the product into your mouth and puffing," he explained.
"A critical question has been: how toxic are e-cigarettes?" said Dr. Michael Blaha, director of clinical research at the Ciccarone Center for the Prevention of Heart Disease at Johns Hopkins Medicine in Baltimore. "This is vitally important to understand as we assess the potential benefits of e-cigarettes as cessation aids versus the very real harms of 'sole e-cigarette' use among young non-smokers picking up e-cigarettes as the first tobacco product."
This study "will be very important to a wide array of researchers," Blaha, who was not involved in the research, said by email. "The study shows that while e-cigarettes are clearly associated with less toxic exposure than combustible cigarettes, they are certainly associated with more exposure than complete non-use of tobacco. In other words, e-cigarettes are 'safer' than traditional cigarettes, but are not themselves 'safe.' In particular, e-cigarettes are associated with volatile organic compounds and heavy metals that are known to be associated with cardiovascular disease."