A new study by American and Polish researchers found that tobacco smokers who switched to e-cigarettes substantially reduced their exposure to carcinogens (cancer-causing chemicals) and toxic substances after only two weeks, with their nicotine exposure remaining the same.
The e-cigarette users also reported significant improvements in chest tightness and visual disturbances, as well as a decline in nicotine withdrawal symptoms over the course of the study.
The study “Exposure to Nicotine and Selected Toxicants in Cigarette Smokers who Switched to Electronic Cigarettes: A Longitudinal Within-Subjects Observational Study” was published in the Aug. 17, 2016 advance access issue of Nicotine & Tobacco Research, one of the world’s few peer-reviewed journals devoted exclusively to the study of nicotine and tobacco.
The study was conducted between March and June 2011 at the Medical University of Silesia, the largest medical school in Poland. It measured seven nicotine metabolites and 17 tobacco smoke exposure biomarkers in the urine samples of 20 smokers collected before and after switching to pen-style M201 e-cigarettes for 2 weeks.
Biomarkers measured were metabolites of 13 major carcinogens and toxicants in cigarette smoke. Changes in urine biomarkers concentration were tested.
Metabolites are the intermediate products of metabolic reactions catalyzed (caused or accelerated) by various enzymes that naturally occur within cells. Biomarkers are measurable substances in humans whose presence is indicative of some phenomenon such as disease, infection, or environmental exposure.
The study authors are scientists from the Department of Health Behavior, Division of Cancer Prevention and Population Sciences, Roswell Park Cancer Institute in New York; Department of General and Analytical Chemistry, Medical University of Silesia in Poland; and Division of Clinical Pharmacology and Experimental Therapeutics, Departments of Medicine and Bioengineering and Therapeutic Sciences, University of California San Francisco.
The study was supported by the Ministry of Science and Higher Education of Poland. The National Institutes of Health provided support for instrumentation and analytical chemistry performed at the UCSF.
In total, 45 percent of participants reported complete abstinence from cigarette smoking after two weeks; 55 percent reported continued smoking.
Levels of total nicotine and some polycyclic aromatic hydrocarbon metabolites did not change after switching from tobacco to e-cigarettes. All other biomarkers, including those for known carcinogens in tobacco, significantly decreased after one week of using e-cigarettes.
“To our knowledge, this is the first study that demonstrates that substituting tobacco cigarettes with an e-cigarette may reduce user exposure to numerous toxicants and carcinogens otherwise present in tobacco cigarettes. Data on reduced exposure to harmful constituents that are present in tobacco cigarettes and e-cigarettes can aid in evaluating e-cigarettes as a potential harm reduction device,” the authors of the study said.
Virtually all nicotine metabolites in urine remained unchanged among the majority of study participants over the two-week period, suggesting that nicotine intake in smokers who used e-cigarettes remained stable. This finding confirms previous findings from laboratory studies showing that e-cigarettes effectively deliver nicotine to blood.
“As nicotine is the substance in tobacco cigarettes that contributes to tobacco addiction, sustained levels of nicotine delivery have important implications for the potential effectiveness of e-cigarettes as a harm reduction device. Future studies should evaluate long-term effects of inhaled nicotine in regular established users of e-cigarettes,” the study authors wrote.