Exposure to Nicotine and Selected Toxicants in Cigarette Smokers Who Switched to Electronic Cigarettes: A Longitudinal Within-Subjects Observational Study.
BACKGROUND
Electronic cigarettes (e-cigarettes) are purported to deliver nicotine aerosol without any toxic combustion products present in tobacco smoke. In this longitudinal within-subjects observational study, we evaluated the effects of e-cigarettes on nicotine delivery and exposure to selected carcinogens and toxicants.


METHODS
We 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 were metabolites of 13 major carcinogens and toxicants in cigarette smoke: one tobacco-specific nitrosamine (NNK), eight volatile organic compounds (1,3-butadiene, crotonaldehyde, acrolein, benzene, acrylamide, acrylonitrile, ethylene oxide, and propylene oxide), and four polycyclic aromatic hydrocarbons (naphthalene, fluorene, phenanthrene, and pyrene). Changes in urine biomarkers concentration were tested using repeated measures analysis of variance.


RESULTS
In total, 45% of participants reported complete abstinence from cigarette smoking at 2 weeks, while 55% 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 significantly decreased after 1 week of using e-cigarettes (p < .05). After 1 week, the greatest percentage reductions in biomarkers levels were observed for metabolites of 1,3-butadiene, benzene, and acrylonitrile. Total NNAL, a metabolite of NNK, declined by 57% and 64% after 1 and 2 weeks, respectively, while 3-hydroxyfluorene levels declined by 46% at week 1, and 34% at week 2.


CONCLUSIONS
After switching from tobacco to e-cigarettes, nicotine exposure remains unchanged, while exposure to selected carcinogens and toxicants is substantially reduced.


CONCLUSIONS
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.
Department of Health Behavior, Roswell Park Cancer Institute, Buffalo, NY.|Department of General and Analytical Chemistry, Medical University of Silesia, Sosnowiec, Poland.
Maciej L
ML
Goniewicz
Department of General and Analytical Chemistry, Medical University of Silesia, Sosnowiec, Poland.
Michal
M
Gawron
Department of Health Behavior, Roswell Park Cancer Institute, Buffalo, NY.
Danielle M
DM
Smith
Division of Clinical Pharmacology and Experimental Therapeutics, Departments of Medicine and Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.
Margaret
M
Peng
Division of Clinical Pharmacology and Experimental Therapeutics, Departments of Medicine and Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.
Peyton
P
Jacob
Division of Clinical Pharmacology and Experimental Therapeutics, Departments of Medicine and Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA.
Neal L
NL
Benowitz
D000328:Adult; D015415:Biomarkers / Q000032:analysis* / Q000652:urine; D002273:Carcinogens / Q000032:analysis*; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000032:analysis* / Q000652:urine; D011044:Poland; D016540:Smoking Cessation / Q000379:methods*; D000074606:Smoking Prevention; D011795:Surveys and Questionnaires; D055815:Young Adult
D015415:Biomarkers; D002273:Carcinogens; D009538:Nicotine